Units (Forces and Motion)
3 marks · HardThe diagram below shows the results of an experiment to measure the movement of a toy truck.
| Distance travelled (cm) | Time taken (ms) |
|---|---|
| 120 | 400 |
| 85 | 280 |
Convert the distances and times for both runs to SI base units, giving your answers as decimals with the correct units and symbols.
State the SI base unit and symbol for length and for time.
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) — · must show 1.20 m, 0.400 s; 0.85 m, 0.280 s
(b) metre (m) for length, second (s) for time · must show metre (m), second (s)
Common mistakes: confusing cm and m or ms and s; giving value but omitting the unit symbol
Show mark scheme and worked solution
Marking points
M1 (a) · 1 mark · Correctly converts distance from cm to m and time from ms to s for at least one set.
A1 (a) · 1 mark · All conversions completed accurately, with correct units and symbols for both runs.
B1 (b) · 1 mark · States SI base unit and symbol for both length and time.
Worked solution
a) Convert cm to m: divide by 100; convert ms to s: divide by 1000.
For first run: 120 cm = 1.20 m; 400 ms = 0.400 s
For second run: 85 cm = 0.85 m; 280 ms = 0.280 s
b) The SI base unit for length is metre (m), and for time is second (s).