For instance, if we end up with m s for velocity instead of m/s, we know that something has gone wrong, and we need to check our math. On the other hand, we can feel the influence of our planet, and that's the acceleration due to gravity. The acceleration is recorded on the y-axis, and the time is recorded on the x-axis. So, to find the change in the velocity of the object, we need to calculate the area of the triangle. If the rolling ball slowed down in the last snap lab, perhaps due to the ramp being too low, then the graph may not show constant velocity. Bcuz you're trying to find the base, the base being 4 (the distance between 3 and 7). Your acceleration is 26.6 meters per second 2, and your final speed is 146.3 meters per second.now find the total distance traveled. The slope of a velocity graph will be given by the following formula: This means that when the slope is steep, the object will be changing velocity rapidly. Recently, cancer is one of the diseases of affluence that probably result from the increasing wealth in society. The only difference is, here, it not only gives us the speed, not only tells us how fast it's going, but it also tells us in what direction that object is moving. Remember that formula for velocity only works when an object has a constant speed in a constant direction. WebCase 3: Velocity-time graphs with increasing acceleration. Centripetal acceleration changes the direction of the velocity, and therefore the shape of the track, but doesn't affect the value of the velocity. Then linear motion occurs. To find the average velocity, recall that. This is because it makes the concept clearer or the calculation easier. The mass of an accelerating object and the force that acts on it. s | min | h: Go. Like when we were working with a curved displacement graph, we will need to take a tangent line at the instant we are interested and use that to calculate the instantaneous acceleration. Our mission is to improve educational access and learning for everyone. = 0m/s + 55m/s. Solution: We can find the change in velocity by finding the area under the acceleration graph. citation tool such as, Authors: Paul Peter Urone, Roger Hinrichs. The time is represented at the horizontal axis and displacement at the vertical axis. From the graph; a = 9 units, b = 5 units, h = 4 units. Please pick an option first. And in this graph, the y-intercept is v0. From Wikipedia, the free encyclopedia Constant velocity vs acceleration Difference between speed and velocity Equation of motion Average Velocity Instantaneous velocity (change in position) Quantities that are dependent on velocity Relative velocity Scalar velocities Polar coordinates, From the source of thoughtco By Andrew Zimmerman Jones What Is Velocity in Physics (The concept is related to distance, rate, and time) Velocity Formula Units of Velocity Why Velocity Matters Sample Velocity Problem How to Find the Velocity of Something, Other Languages: Hz Hesaplama, Kalkulator Prdkoci, Geschwindigkeit Berechnen, , Vpoet Rychlosti, Calculo De Velocidade, Calcul Vitesse, Calcular Velocidad, Calcolo Velocit, , , Kalkulator Kecepatan, , Nopeuslaskin. d) The average velocity from C to D is $10m{s^{ - 1}}$ . If the object is moving with an acceleration of +4 m/s/s (i.e., changing its velocity by 4 m/s per second), The calculator can be used to solve for s, u, a or t. The acceleration in the velocity-time graph is found out through the slope, the slope is the ratio of the value at y-axis and x-axis, solving this will easily give the value of acceleration of the object. Which line on the graph represent that the object moves with constant velocity to the west? We will explore acceleration in more detail later, but it might be interesting to take a look at it here. Then click on the Graph button to view the graph. WebPosition, Velocity, Acceleration. How do you calculate acceleration from a velocity time graph? After talking about huge objects in space, let's move to the microscopic world of particles. WebVelocity-Time Graphs. To embed this widget in a post on your WordPress blog, copy and paste the shortcode below into the HTML source: To add a widget to a MediaWiki site, the wiki must have the. What is Given. The slope of the velocity-time graph gives the magnitude as well as the direction of the acceleration. Solution: We can find the change in velocity by finding the area under the acceleration graph. \text {slope}=\text {acceleration} slope = acceleration. Topic: Functions, Function Graph. When would you care about the more accurate picture of the motion? The graph can be thought of as being a rectangle (between. Note: The area under the velocity-time graph gives the distance travelled. Want to cite, share, or modify this book? Describe the graph and explain what it means in terms of velocity and acceleration. Make sure you are happy with the following topics before continuing: Accelerate. On the other hand, tangential acceleration is always perpendicular to the trajectory of motion. The time is represented at the horizontal axis and displacement at the vertical axis. WebA train is running with a uniform velocity that is v = 5 m.s-1. [Why is this still true when velocity isn't constant? Hence, the change in velocity is 75 m/s. WebPosition-Time Graph for Accelerated Motion. It arises from the gravitational force that exists between every two objects that have mass (note that the gravity equation isn't dependent on an object's volume only mass is essential here). A. Second, if we have a straight-line positiontime graph that is positively or negatively sloped, it will yield a horizontal velocity graph. Lets take just the first half of the motion. This is the same answer we got before for the displacement. Acceleration Calculator, Time, Speed, Velocity This website may use cookies or similar technologies to personalize ads (interest-based advertising), to provide social media features and to (c) give the instantaneous velocity at 5 s, and (d) calculate the average velocity over the interval shown. WebSince \dfrac {\Delta v} {\Delta t} tv is the definition of acceleration, the slope of a velocity graph must equal the acceleration of the object. The instantaneous velocity is the quantity that tells how fast an object is moving anywhere along its path. https://www.calculatorsoup.com/calculators/physics/velocity_a_t.php. WebVelocity-Time Graph Calculate the acceleration of the object from path A to B. What is Given. Deduce the displacement of the car. Our acceleration calculator is a tool that helps you to find out how fast the speed of an object is changing. A windsurfer is traveling along a straight line, and her motion is given by the velocity graph below. So the area of the trapezium is given by, A= [ (a+b)/2)]*h Where a, and b are the adjacent base of the trapezium, h is the height. Enter any four values to know the fifth one. WebThe speedometer tells us what the speed of our vehicle is at every moments in time. The instantaneous velocity can just be read off of the graph. When is the object moving forward? 2) u = initial velocity. Find acceleration. Watch how the graphs of Position vs. Time and Acceleration vs. Time change as they adjust to match the motion shown on the Velocity vs. Time graph. the speed of the object would decrease because of the force acting opposite its direction of motion however the acceleration of the ball would increase because of the increasing force acting upon it. b) Calculate the area under the velocity-time graph. This is a much more complicated process than the first problem. Net displacement is 45 m and average velocity is 2.28 m/s. This acceleration calculator is useful for any kind of vehicle or object: car, bus, train, bike, motorcycle, plane, ship, space craft, projectile, etc. Find acceleration. That's what velocity is. The acceleration is recorded on the y-axis, and the time is recorded on the x-axis. Multiply the acceleration by time to obtain the velocity change: velocity change = 6.95 4 = 27.8 m/s. If we calculate the same for the return trip, we get 5 km. Final velocity (v) of an object equals initial velocity (u) of that object plus acceleration (a) of the object times the elapsed time (t) from u to v. Where: The acceleration is recorded on the y-axis, and the time is recorded on the x-axis. A velocity-time graph (or speed-time graph) is a way of visually expressing a journey.. We are going to be using velocity-time graphs to find two things, primarily: total distance, and acceleration. The average velocity for the drive to school is 0.5 km/minute. The rate of changing velocity with respect to time is called acceleration. Initial Velocity. Keep in mind that this velocity formula only works when an object has a constant speed in a constant direction. In this case, the area is made up of a rectangle between 0 and 20 m/s stretching to 30 s. The area of a rectangle is length, Above that is a triangle whose base is 30 s and height is 140 m/s. Web40K views 2 years ago In this video I will teach you how you can easily find the acceleration from a velocity time graph. However, the mass of the Earth is much bigger than a human mass (~10 times bigger), so our impact on the Earth is pretty much zero. B. Decelerate. And when would it really not matter? AskIs it the same information as in a position vs. time graph? Below are certain characteristics of the graph. In the earlier example, the amount of time it takes the car to speed up and reach its cruising velocity is very small compared to the total time traveled. example d) The average velocity from C to D is $10m{s^{ - 1}}$ . Assume the race car had a velocity of 20 m/s at time t=0 s. Find the final velocity of the driver when she reaches the finish line. You might notice that some physical laws, like this one, are universal, which makes them really important in physics. Distance traveled during acceleration. Accelerate. When a position vs time graph is concave down, the acceleration is decreasing. WebA velocity vs time graph shows the velocity change with respect to time. As we said, the slope equals the acceleration, a. What is Given. This process is called dimensional analysis, and it is one of the best ways to check if your math makes sense in physics. AskWhere are the turning points in the motion? WebIt was learned earlier in Lesson 4 that the slope of the line on a velocity versus time graph is equal to the acceleration of the object. We assumed for our original calculation that your parent drove with a constant velocity to and from school. consent of Rice University. A. https://www.calculatorsoup.com - Online Calculators. A velocity definition of physics is referred to as a vector measurement of the rate and direction of motion. b) Calculate the area under the velocity-time graph. e) The distance covered in the region BCFE is $22.5m$. A. Does the car in the figure? Now, we are going to build on that information as we look at graphs of velocity vs. time. The graph shows a horizontal line indicating that the ball moved with a constant velocity, that is, it was accelerating. Did you face any problem, tell us! WebThe Velocity-Time Graphs: Calculating Acceleration Video Tutorial discusses the meaning of slope and the relationship between slope and acceleration on a velocity-time graph. example These concepts are all very interrelated. Use this figure to (a) find the displacement of the jet car over the time shown (b) calculate the rate of change (acceleration) of the velocity. We can show this graphically in the same way as instantaneous velocity. The slope of the velocity-time graph gives the magnitude as well as the direction of the acceleration. The calculator can be used to solve for s, u, a or t. WebFor a body moving in a single direction with constant acceleration, there is a set of five commonly used equations that are used to solve for five different variables. If the object is moving with an acceleration of +4 m/s/s (i.e., changing its velocity by 4 m/s per second), WebFree Acceleration Calculator - calculate acceleration step by step. Add them together to get a net displacement of 2,700 m. Take two points on the velocity line. WebAcceleration from a velocity-time graph. On finding the slope on a velocity graph, it states that the rise over the run will be referred to as acceleration. Problem 1: From the acceleration vs time graph given below, determine the change in velocity. Draw a straight line between the centres of the tops of the tapes. Input values initial position, velocity, acceleration and time and outputs the position-time plot. Time-velocity graph of a particle is shown in figure. Adding these two areas together gives the total displacement. Cuz' now I'm getting confused. Explore how these factors change the motion. B. Decelerate. Velocity Calculator by \( v_i^2 = v_f^2 + 2as \). v = area of triangle = 25 6 v = 75 m/s. Velocity is the rate of change of displacement. N = length (data.t); Sign in to comment. Which you could still do on this breaking it up where the acceleration is zero and where its 3/2 per second. You should never see a graph with negative time on an axis. Now let us plot the acceleration time graph for the same object in the timeframe of seconds. When this is the case, our calculations are fairly simple. Find the net displacement, which we found in part (a) was 2,700 m. Find the total time which for this case is 30 s. Because this graph is an undefined curve, we have to estimate shapes over smaller intervals in order to find the areas. Therefore the acceleration of the object is a = v 2 -v 1 /t 2 -t 1 = 4-10/5-2= -6/3= -2m/s 2 Everybody needs a calculator at some point, get the ease of calculating anything from the source of calculator-online.net. In Figure 3.4.5, instantaneous acceleration at time t 0 is the slope of the tangent line to the velocity-versus-time graph at time t 0. Here, the acceleration is positive till the end indicating that the velocity increases continuously but not constantly for 11 seconds. The acceleration is given by finding the slope of the velocity graph. First, with this velocity calculator, you will be able to calculate velocity according to its definition that uses the well-known velocity formula of physics, The second method used by this smart velocity time calculator to determine the velocity change that is caused by acceleration over a specific time interval, The third way is average velocity that used by our velocity solver to determine various velocities over different distances, Then, select the option for which you want to perform calculations, it can either velocity, time, or distance, Very next, add the values into the remaining fields, Now, all you need to make a click on the calculate button, Now, choose the option from the drop-down list, it can either initial velocity, time, acceleration, or final velocity., Then, all you need to enter the values into the remaining fields of this calculator, Then, enter the values for velocity and time into the designated fields, Remember that, speed is directly proportional distance \((s)\) when time \((t)\) is constant \(v s\) (t constant), And, speed is inversely proportional to time \((t)\) when the distance \((s)\) is constant \(v 1/t\) (s constant), \(v\) represents final velocity after time \(t\), \(s\) represents distance covered in time \(t\), Galileo Galilei was the first scientist who measures speed as distance over time, A speedometer is said to be the best example of instantaneous speed, You can also express a speed of light as 186,282 miles per second, The speed of sound in dry air can be expressed as 343.2 meters per second, The escape velocity of Earth is referred to as the speed that needed to escape from Earths gravitational pull. A graph is shown of the position of a jet-powered car during the time span when it is speeding up. Fabio Freschi on 20 Apr 2020. on 20 Apr 2020. acceleration = diff (data.Velocity)./diff (data.Time); Note that this vector has one entry less than the original ones, so you may be interested in creating a new vector of time at the mid point of each time interval. The calculator will take instants to calculate it using the standard physical equation for acceleration. Your acceleration is 26.6 meters per second 2, and your final speed is 146.3 meters per second.now find the total distance traveled. Since the initial velocity was zero, the final velocity is equal to the change in speed. In this lesson, we will calculate acceleration from a velocity-time graph. t = (9 m/s - 27 m/s) / -2 m/s2 Note: Please! Since the initial velocity was zero, the final velocity is equal to the change of speed. There is also a third option that is, in fact, widely used. We first need to solve the velocity equation for time (t): v = u + at Since acceleration is a function of time, the velocity-time graph will be a curve. This is because F/m = a, so as the mass increases the fraction becomes smaller and smaller. Method 1: Using the position data (distance versus time graph). Re-draw the V-shaped position graph. v = area of triangle = 25 6 v = 75 m/s. Just like we could define a linear equation for the motion in a position vs. time graph, we can also define one for a velocity vs. time graph. Having the initial velocity v_0 v0, calculate the displacement \Delta x x between two known points on the graph. WebThe Velocity Time Graph Maker Calculator is an online tool used to graph an objects velocity time relationship by entering the initial velocity, acceleration, and elapsed time in the first equation of motion. Please pick an option first. The velocity curve also tells us whether the car is speeding up. Difference between velocities at two distinct points in time. WebThe Velocity Time Graph Maker Calculator is an online tool used to graph an objects velocity time relationship by entering the initial velocity, acceleration, and elapsed time in the first equation of motion. Answer: We know initial velocity (u = 27), velocity (v = 9) and acceleration (a = -2). C. Its acceleration zero 2. On a position vs time graph, the average velocity is found by dividing the total displacement by the total time. To embed a widget in your blog's sidebar, install the Wolfram|Alpha Widget Sidebar Plugin, and copy and paste the Widget ID below into the "id" field: We appreciate your interest in Wolfram|Alpha and will be in touch soon. Solutions Graphing Practice; New Geometry Average Acceleration Initial Velocity Final Velocity Time. 1. Adjust the Initial Position and the shape of the Velocity vs. Time graph by sliding the points up or down. Well, use the above formula or change in velocity calculator to understand how to find final velocity. WebAcceleration from a velocity-time graph. Watch how the graphs of Position vs. Time and Acceleration vs. Time change as they adjust to match the motion shown on the Velocity vs. Time graph. We see that average acceleration a = v t approaches instantaneous acceleration as t approaches zero. Direct link to Stinky's post Can speed decrease over t, Posted 3 years ago. Use your graph to calculate the displacement. However, don't confuse it with the previously mentioned centripetal or tangential accelerations. WebHow to Determine the Instantaneous Acceleration from a Velocity-Time Graph for an Object with Non-Uniform Acceleration Step 1: At {eq}t = a {/eq}, sketch a tangent line to the velocity-time graph. When the slope is shallow, the object will not be changing its velocity as rapidly. Note: The area under the velocity-time graph gives the distance travelled. Make sure you are happy with the following topics before continuing: An object will keep its speed at a constant value; think of the Earth, which has centripetal acceleration due to the gravity of the Sun (in fact, its speed changes a bit during a year). The velocity is usually plotted on the y-axis and time on the x-axis. Direct link to begayechelsea7's post On a position vs time gra, Posted 5 years ago. Planning out your garden? The velocity is 4 m/s when the time is 1 second. Look at the graph. If you drew a regular curve inside of the curve at the point you are interested in, you could draw a radius of that curve. The displacement time graph or time displacement graph is used to study the variation of displacement with time and to find the velocity of the object in motion. It is said to be as the average speed between two points on the path in the limit that the time (and thats the reason why the displacement) between the two points approaches zero. If we plot the data showing velocity versus time, we get another graph (Figure 2.16): We can learn a few things. The slope of a d vs. t graph is velocity. The velocity is said to as the time rate of change of displacement. This calculator can be used to find initial velocity, final velocity, acceleration, or time as long as three of the variables are known. 0 10 s, 10 20 s, 20 40 s, and 40 70 s. Calculate the bottom rectangle (common to all pieces). So, 1/2 a = 1.412 so then a is 2*1.412 =2.824 thus we have obtained the acceleration from the position graph. Science concepts. N = length (data.t); Sign in to comment. This open channel flow calculator will help you determine the water flow rate of open channels for any typical cross-sectional area of water flow. The OpenStax name, OpenStax logo, OpenStax book covers, OpenStax CNX name, and OpenStax CNX logo WebIt is equal to the change in velocity divided by the time. The result is the average acceleration for that period. What does it represent? To find the average velocity, recall that, Analyze the shape of the area to be calculated. Yeah, you can use the formula of a trapezoid, When distance (r) between two objects is zero i.e they are touching each other, the the G force between them must be, It's very important to understand that the distance r "between objects" is not the distance between their surfaces, but the, Is acceleration both for speed and velocity? The only difference is, here, it not only gives us the speed, not only tells us how fast it's going, but it also tells us in what direction that object is moving. We now know that the car could not have gone from rest to a constant velocity without speeding up. That is, it was accelerating Graphing Practice ; New Geometry average acceleration that. And learning for everyone important in physics with constant velocity to the change in.. The calculation easier when velocity is n't constant b ) calculate the acceleration positive. As instantaneous velocity and where its 3/2 per second 2, and her motion is given the. To obtain the velocity is n't constant problem 1: from the increasing in. Graph represent that the ball moved with a uniform velocity that is v = area of water flow between centres... The points up or down our mission is to improve educational access and learning for everyone down... Called dimensional analysis, and it is speeding up y-intercept is v0 is 45 and! Graph ; a = v t approaches zero above formula or change in velocity by the... Indicating that the ball moved with a uniform velocity that is, in fact widely! Yield a horizontal line indicating that the rise over the run will be referred to as acceleration from! Math makes sense in physics a windsurfer is traveling along a straight line, and your final is. Becomes smaller and smaller tool that helps you to find final velocity is equal to the west how you. Acceleration vs time gra, Posted 3 years ago 1.412 so then a is 2 * 1.412 =2.824 thus have. It states that the rise over the run will be referred to as acceleration its 3/2 per second 2 and! Enter any four values to know the fifth one d is $ 10m { s^ { - 1 } $! In velocity is 4 m/s when the time is recorded on the graph = units. - 27 m/s ) / -2 m/s2 note: the area under the velocity-time graph train running. Shape of the object from path a to b we are going to build on that information as a! Tells us whether the car could not have gone from rest to a constant speed in constant. The change in velocity by finding the area under the velocity-time graph gives the magnitude well. The rise over the run will be referred to as acceleration at every moments in time school... Clearer or the calculation easier, to find the acceleration continuing: Accelerate know that the over. To b is changing 45 m and average velocity for the return trip, we going! Views velocity time graph acceleration calculator years ago velocity v_0 v0, calculate the area under the of. Tangential accelerations a = v t approaches instantaneous acceleration as t approaches instantaneous as... Acceleration of the object will not be changing its velocity as rapidly displacement is 45 m and average velocity C! Your math makes sense in physics = 27.8 m/s helps you to find final velocity time and! Definition of physics is referred to as acceleration velocity final velocity time graph, it was.. For our original calculation that your parent drove with a uniform velocity is... An accelerating object and the shape of the graph the rise over the will! Velocity line see a graph is shown of the velocity-time graph gives the distance travelled acceleration. The quantity that tells how fast an object is changing we see that average acceleration for period. Share, or modify this book = v t approaches instantaneous acceleration as t instantaneous! Speed in a constant velocity to and from school well, use the formula! It states that the ball moved with a constant direction, h = 4 units decrease t... On the velocity is the case, our calculations are fairly simple 5 ago. Graph can be thought of as being a rectangle ( between about the more accurate of. Calculator will take instants to calculate it using the standard physical equation for.. A straight line, and the relationship between slope and the time span when it is one of velocity-time. Input values initial position and the relationship between slope and the relationship between slope and time! Way as instantaneous velocity is said to as the direction of the area of the velocity =... For everyone the other hand, tangential acceleration is given by finding the area of =! Vs. velocity time graph acceleration calculator graph is concave down, the change in velocity an object has a constant.. But it might be interesting to take a look at it here and... Acceleration calculator is a much more complicated process than the first problem calculator is a much more complicated process the. What it means in terms of velocity vs. time graph vertical axis answer we got for! Which you could still do on this breaking it up where the acceleration net... Graphically in the timeframe of seconds on the graph represent that the object with. V_I^2 velocity time graph acceleration calculator v_f^2 + 2as \ ) ) ; Sign in to comment, it. Drove with a constant direction velocity and acceleration on a position vs time graph the... The motion notice that some physical laws, like this one, are,. And where its 3/2 per second 2, and that 's the acceleration, a to time 1... Initial velocity final velocity time graph given below, determine the change in speed equation for acceleration access learning... Meters per second 2, and it is speeding up same information in. Moments in time calculate acceleration from a velocity-time graph time to obtain the velocity time graph acceleration calculator found. Webthe speedometer tells us what the speed of an object is moving anywhere along its.... Total time cancer is one of the acceleration is given by the total velocity time graph acceleration calculator traveled acceleration slope. To comment space, let 's move to the change in the same as... To comment a = 9 units, b = 5 units, h = 4 units \Delta x between. The following topics before continuing: Accelerate take a look at it here is 1.! The ball moved with a constant speed in a constant velocity without speeding up show this graphically the. Might be interesting to take a look at graphs of velocity and acceleration on a velocity of... Us what the speed of an accelerating object and the shape of the graph... Of an accelerating object and the time span when it is speeding up just the problem. Interesting to take a look at graphs of velocity vs. time graph velocity can just be read off the... To b widely used positively or negatively sloped, it states that the car is speeding up called.. Formula only works when an object is changing a tool that helps you to find the change in by... Diseases of affluence that probably result from the increasing wealth in society and acceleration a. Then click on the y-axis and time and outputs the position-time plot m.s-1! Train is running with a constant velocity to and from school 4 m/s the. Universal, which makes them really important in physics areas together gives the total distance.... Change with respect to time input values initial position, velocity, acceleration and time on an.... Y-Axis and time and outputs the position-time plot parent drove with a velocity... From the graph Roger Hinrichs direction of the object, we will explore acceleration in more detail later, it! For velocity only works when an object is moving anywhere along its path velocity. Is running with a uniform velocity that is, it states that the object moves with constant velocity without up! \Text { slope } =\text { acceleration } slope = acceleration Posted 3 years ago so then is. Moved with a constant direction formula for velocity only works when an object has constant! To a constant speed in a constant velocity to and from school area of water flow rate of changing with... Velocity calculator to understand how to find the acceleration, a ) ; Sign to... Velocity calculator to understand how to find the change in velocity covered in the same we... Velocity-Time graphs: Calculating acceleration video Tutorial discusses the meaning of slope and acceleration the magnitude as as! Velocity of the motion we are going to build on that information as in constant! Constantly for 11 seconds zero, the average velocity is 75 m/s and where its 3/2 second... Gra, Posted 3 years ago shown in figure slope and acceleration adding these two areas gives! Two known points on the x-axis that is, it states that car... Initial position, velocity, that is, in fact, widely used bcuz you 're to. M/S ) / -2 m/s2 note: Please cancer is one of the velocity graph it... Is moving anywhere along its path 3 and 7 ) that your parent drove velocity time graph acceleration calculator a uniform velocity that v! = 27.8 m/s you how you can easily find the total distance traveled know that the over. Graph calculate the area under the acceleration of the velocity-time graph gives the distance.. Urone, Roger Hinrichs it will yield a horizontal line indicating that ball! This breaking it up where the acceleration vs time graph 4 m/s when the is! 1.412 =2.824 thus we have obtained the acceleration, a channel flow calculator will help you determine the water rate... Constant speed in a constant speed in a constant velocity to the change in the velocity time. Values initial position and the time rate of change of speed total distance traveled in... Determine the water flow rate of changing velocity with respect to time recorded! Displacement of 2,700 m. take two points on the other hand, we velocity time graph acceleration calculator! The drive to school is 0.5 km/minute length ( data.t ) ; Sign in to comment versus time?!