The graph shows how the velocity of a cyclist changes during the first 10 s of a race.
(a) Describe the motion of the cyclist between 4 s and 10 s. [1]
(b) Calculate the acceleration of the cyclist during the first 4 s. [2]
(c) Calculate the distance travelled by the cyclist in the 10 s. [2]
- (a) constant velocity / constant speed (of 12 m/s) allow steady speed; allow zero acceleration / not accelerating; reject 'stationary' / 'not moving'(1)
- (b) $a = \dfrac{(v-u)}{t} = \dfrac{12}{4}$(1)
- (b) 3.0 m/s² (3 m/s² acceptable)(1)
- (c) area under graph seen, e.g. $\tfrac{1}{2}\times4\times12$ (= 24) and $6\times12$ (= 72)(1)
- (c) 96 m(1)
- Answer: (a) constant velocity of 12 m/s (b) 3.0 m/s² (c) 96 m
- Examiner tip: Distance is the area under a velocity–time graph, not the gradient — split the area into a triangle and a rectangle.