The velocity-time graphs of a car and a scooter are shown. Find (i) the difference between distances travelled in 15 s and (ii) the time at which the car catches the scooter.

Question

G1 Physics · Accepted Answer

From the graph, in the first 15 s the scooter travels 30×15=450 m, while the car travels triangular area (1/2)(15)(45)=337.5 m; difference=112.5 m. After 15 s, relative speed=45-30=15 m s⁻¹, so catch-up time=112.5/15=7.5 s. Thus catch occurs at 22.5 s. Hence option C.