Distance-time graphs
3 marks · HardA group of students investigate how a trolley moves down a ramp. They record the time taken for the trolley to travel different distances starting from rest.
| Distance (m) | Time (s) |
|---|---|
| 0.5 | 2.0 |
| 1.0 | 2.8 |
| 1.5 | 3.4 |
Using the table, calculate the average speed of the trolley between 0.5 m and 1.5 m.
Explain why the average speed increases as the distance increases.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
Show answer
(a) m/s · must show Correct use of speed = distance / time, Correct subtraction for interval
(b) Because the trolley accelerates down the ramp, so it goes faster as it moves further. · must show References acceleration, Speed increases with distance
Common mistakes: Using incorrect time interval; Not explaining effect of acceleration
Show mark scheme and worked solution
Marking points
M1 (a) · 1 mark · Correctly identifies distance and time interval for the section 0.5 m to 1.5 m
A1 (a) · 1 mark · Correct calculation: average speed = 0.71 m/s (accept 0.714 within tolerance) (follow-through)
B1 (b) · 1 mark · Explains speed increases due to acceleration down the ramp
Worked solution
(a) The distance travelled is 1.5 m − 0.5 m = 1.0 m. The time taken is 3.4 s − 2.0 s = 1.4 s.
(b) The trolley speeds up as it goes down the ramp because gravity accelerates it, so its average speed increases over greater distances.