Speed, velocity and distance-time graphs
Grade 8 Science Worksheet
Circle the best answer, or write your answer on the line.
East is positive. Bo rides 90 m east in 30 s, then 10 m west in 10 s. What is the average velocity for the whole ride?
East is positive. Esme's robot rolls 75 m east in 15 s, then 15 m west in 5 s. What is its average velocity?
Read this first
Object on a straight track (example data)
time (s) position (m east of the start) 0 0 2 10 6 26 8 12 East is positive. Use the table. During which interval is the object's speed greatest, Jun?
- 6 s to 8 s, at a velocity of −7 m/s, so the object moves west fastest there
- 0 s to 2 s, since +5 m/s is the greatest velocity in the table
- 2 s to 6 s, since the position changes by 16 m, the greatest change in any interval
- 2 s to 6 s, since the object is farthest from the start, at 26 m, at the end of it
East is positive. Use the table. What was the object's velocity from 3 s to 6 s, Kira?
- 4 m/s east: the position changes by 4 m each second, so the object moves east
- −4 m/s, so the object moves more slowly than an object that is at rest
- −12 m/s: the position falls by 12 m between the readings at 3 s and 6 s
- −4 m/s: the object moves 4 m toward the west each second, so the velocity is negative
Scooter on a straight path (example data)
time (s) position (m east of the start) 0 0 3 15 6 27 9 18 East is positive. Which statement does the table support, Luz?
- The scooter keeps moving east after 6 s, at a speed of 3 m/s, since it moves at a steady rate
- The velocity is positive until 6 s and negative after, so the scooter turned around at 6 s
- The scooter slows down after 6 s, because −3 is a smaller number than +4
- The scooter moves fastest from 3 s to 6 s, since it is farthest from the start at 6 s
Milo graphs a walk away from home and back. Which story fits the graph?
- Walks up a hill, rests at the top for 10 s, and then walks down the other side
- Walks away at a steady pace, rests for 10 s, then returns more slowly because the line falls
- Walks away at a steady pace, rests for 10 s, then returns home at twice the speed
- Walks away at a steady pace, rests for 10 s, then returns home at the same speed as before
Noah graphs two buses, P and Q. What does the point where the lines cross at 10 s show?
- Both buses stop at 10 s, because the lines end at the point where they meet
- Q is faster, since it started 20 m from the start while P started at 0 m
- P and Q have the same speed at 10 s, because the two lines meet at that point
- Both are at 30 m from the start at 10 s, and P is moving faster than Q
Pia graphs two trains, A and B, over 20 s. Which statement does the graph support?
- A and B both travel 40 m in 20 s, but B moves more slowly at first and faster later
- B slows down after 10 s, because the steeper piece of its line means a slower train
- B climbs a hill that gets steeper after 10 m, while A is on flat ground
- A and B move at the same speed the whole time, because their lines meet again at 20 s
0. Ren times a cart over 2 m three times. Which is the best estimate of the cart's average speed?
- About 1.0 m/s, from the 2 m distance and the mean time of 2.0 s
- About 2.0 m/s, since the mean time of the three trials is 2.0 s
- About 1.05 m/s, from the 2 m distance and the fastest time of 1.9 s
- About 0.33 m/s, from the 2 m distance and the total of 6.0 s for the three trials together
0. Tala wants to know whether ball A is faster than ball B. Which change makes the test fair?
- Roll both balls over the same distance on the same surface, so only the ball differs
- Roll ball A on carpet over 3 m and ball B on tile over 5 m, so the surfaces are swapped
- Time each ball three times and compare the means, keeping tile for A and carpet for B
- Roll ball A over 5 m on tile and ball B over 3 m on carpet, so the distances are swapped