Question

Give me the correct answer of this question ​

Answer 1

Answer:

QUESTION:

A car of mass 480 kg moving at a speed of 54 kmph, is stopped by applying brakes in 10 s. Calculate the force applied by the brakes.

ANSWER:

The force applied by the brakes = 720 N.

GIVEN:

A car of mass 480 kg moving at a speed of 54 kmph, is stopped by applying brakes in 10 s.

TO FIND:

The force applied by the brakes.

EXPLANATION:

★ v = u + at

=> u = 54 kmph = (54 × 5) ÷ 18 = 15 m/s

=> v = 0

=> t = 10 s

=> 0 = 15 + 10a

=> 10a = - 15

=> a = - 1.5 m/s²

★ Force = ma

=> m = 480 kg

=> a = - 1.5 m/s²

=> F = - 480 × 1.5

=> F = - 720 N. [Negative sign indicates force is applied in opposite direction to the motion of the car ]

Hence the force applied by the brakes = 720 N.