The difference between speed and velocity
4 marks · NormalA runner accelerates from rest to a speed of 6 m/s in 3 s.
(a)[1 mark]
State the initial velocity of the runner.
(b)[2 marks]
Calculate the acceleration.
(c)[1 mark]
State the SI unit for acceleration.
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(a) 0 m/s
(b) 2.0 m/s^2
(c) m/s^2
Common mistakes: Using final velocity as initial
Show mark scheme and worked solution
Marking points
B1 (a) · 1 mark · Gives initial velocity as 0 m/s.
M1 (b) · 1 mark · Uses with numbers substituted.
A1 (b) · 1 mark · Accurately calculates acceleration as 2.0 m/s^2.
B2 (c) · 1 mark · Gives correct SI unit: m/s^2.
Worked solution
a) Initial velocity, u = 0 m/s (from rest).
b) Acceleration:
c) SI unit is m/s^2.