A car starts from rest and accelerates uniformly at 2 m/s^2 for 4 s. What is its final velocity?

A car starts from rest and accelerates uniformly at 2 m/s^2 for 4 s. What is its final velocity?

• A. 4 m/s
• B. 8 m/s
• C. 16 m/s
• D. 2 m/s

Answer: (B)

Constant acceleration means velocity changes by a fixed amount each second. With starting velocity zero, the final velocity after time t is v = a t. Here the acceleration is 2 m/s^2 and the time is 4 s, so v = 2 × 4 = 8 m/s. Therefore, the car’s final velocity is 8 m/s. The other values would require a different time or a nonzero starting speed.

Constant acceleration means velocity changes by a fixed amount each second. With starting velocity zero, the final velocity after time t is v = a t. Here the acceleration is 2 m/s^2 and the time is 4 s, so v = 2 × 4 = 8 m/s. Therefore, the car’s final velocity is 8 m/s. The other values would require a different time or a nonzero starting speed.