A car accelerates uniformly from rest to a speed of 20 m/s in 5 seconds. What is the magnitude of its acceleration?

✓ Correct Answer: Option B

Acceleration is defined as the change in velocity divided by the time taken. Here, a = Δv/Δt = (20 m/s - 0 m/s) / 5 s = 4 m/s^2.