A motorcycle is moving at a speed of 21 m/s. The driver applies the brakes, giving hum an acceleration of - 2.4 m/s^2. After 2 seconds of braking, what is the speed of the motorcycle?

A. 25.8 m/s

B. 16.2 m/s

C. 4.8 m/s

D. 2.4 m/s

Answer;

B. 16.2 m/s

Explanation;

Using the equation;

v = u + at; where v is the final velocity, u is the initial velocity, a is the acceleration and t is the time taken;

u = 21 m/s, a = - 2.4 m/s^2 and t = 2 seconds

Therefore;

v = 21 + ((-2.4) * 2)

= 21 - 4.8

= 16.2 m/s