Units (Forces and Motion)
3 marks · NormalA runner covers a distance of 800 metres in 200 seconds.
(a)[1 mark]
State the correct SI unit and symbol for speed.
(b)[2 marks]
Calculate the average speed of the runner. Give your answer in SI units.
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(a) metre per second (m/s)
(b) 4.0 m/s
Common mistakes: reversing numerator and denominator
Show mark scheme and worked solution
Marking points
B1 (a) · 1 mark · States the SI unit for speed as metre per second (m/s).
M1 (b) · 1 mark · Applies the correct formula: speed = distance ÷ time.
A1 (b) · 1 mark · Calculates average speed as 4.0 m/s (accept 4 m/s). (follow-through)
Worked solution
a) The SI unit for speed is metre per second (m/s).