Question

A motorcycle moving at a speed of 21 m/s, the rider applies brakes giving it an acceleration of -2.4 m/s². After two seconds of braking, what is the speed of the motorcycle?

Answer 1

After applying brakes with a deceleration of -2.4 m/s² for two seconds, the speed of the motorcycle decreases from 21 m/s to 16.2 m/s.

Step-by-step explanation:

A motorcycle initially moving at a speed of 21 m/s applies brakes, producing a negative acceleration (deceleration) of -2.4 m/s². To determine the speed of the motorcycle after two seconds of braking, we use the equation of motion:

final velocity = initial velocity + (acceleration × time)

Vf = Vi + (a × t)

Where:

• Vi is the initial velocity (21 m/s)
• a is the acceleration (-2.4 m/s²)
• t is the time (2 s)

Substituting the values we get:

Vf = 21 m/s + (-2.4 m/s² × 2 s)

Vf = 21 m/s - 4.8 m/s

Vf = 16.2 m/s

Therefore, after two seconds of braking, the speed of the motorcycle is 16.2 m/s.