Question

Two cars emerge side by side from a tunnel. Car A is traveling with a speed of 60 km/h and has an acceleration of 40 km/h/min. Car B has a speed of 40 km/h and has an acceleration of 60 km/h/min. Which car is passing the other as they come out of the tunnel? Explain your reasoning.

Short answer

Car A is passing car B as they come out of the tunnel, but car B will catch up later.

Step-by-step solution

Step 1. Definition of acceleration

The variation in the velocity of an object with time gives the acceleration of the object. A positive value of acceleration implies that the velocity is increasing with time.

Step 2. Identifying the car passing the other as both come out of the tunnel

As the two cars emerge from the tunnel, the velocity of car A is $60\frac{\mathrm{km}}{\mathrm{h}}$, and that of car B is $40\frac{\mathrm{km}}{\mathrm{h}}$. They are at the same position, but car A has a greater velocity than car B. It implies that car A is passing car B as they come out of the tunnel.

The acceleration of car B is greater than that of car A. Thus, car B will attain greater velocity than at a later point.

Hence, car A is passing car B as they come out of the tunnel, but car B will catch up later.