A runner covers 200 m in 25 s. Calculate the average speed.
A distance-time graph for a walk is a straight line from 0 to 60 m between 0 s and 12 s, then a horizontal line from 12 s to 20 s.
A car accelerates from 8 m/s to 20 m/s in 6 s. Calculate the acceleration.
A speed-time graph shows a car rising from rest to 12 m/s in 4 s, then a constant 12 m/s for 6 s. Use the area to find the total distance travelled.
A cyclist slows from 12 m/s to rest in 4 s. Calculate the deceleration.
Free fall near the Earth's surface.
Total: 15 marks. Original work by the TheLucidSTEM team. Written in the style of the papers; no past paper question is reproduced.
Answer key · full worked solutionsclick to reveal
v = s ÷ t = 200 ÷ 25 = 8 m/s.
(a) speed = gradient = 60 ÷ 12 = 5 m/s.
(b) the line is horizontal, so the walker is stationary (not moving).
a = Δv ÷ Δt = (20 − 8) ÷ 6 = 12 ÷ 6 = 2 m/s².
triangle (0 to 4 s): ½ × 4 × 12 = 24 m.
rectangle (4 to 10 s): 6 × 12 = 72 m.
total distance = 24 + 72 = 96 m.
a = Δv ÷ Δt = (0 − 12) ÷ 4 = −3 m/s², so the deceleration is 3 m/s².
(a) about 9.8 m/s² (accept 10 m/s²).
(b) v = g t = 9.8 × 2 = 19.6 m/s (accept 20 m/s if g = 10 m/s² is used).