Question

An auto driver with a speed of 36km/h sees a child standing in the middle of the road he applies brakes and bring the auto to rest in 2.5sec in timeto save the child the mass of auto and driver is 320kg find the force applied to stop the auto

Answer 1

Answer:

-1280 N

Explanation:

According to the given question,

u = initial velocity = 36 km/h = 36×1000/3600 = 36000/3600 = 10 m/s

v = final velocity = 0 m/s

t = time = 2.5 s

m = mass = 320 kg

a = acceleration and F = force

And we are asked to find force to stop the auto.

We know,

• v = u + at

Putting the values we get,

• 0 = 10+ 2.5 a

• 2.5 a = -10

• a = -10/2.5

• a = -4 m/s^2

Thus acceleration is -4 m/s^2 , here negative sign indicates that acceleration is opposite to the direction of motion i.e, deceleration or retardation.

Again,

• F = ma

Putting the values we get,

• F = 320×(-4)

• F = -1280 N

Thus force is 1280 N, opposite to the direction of motion means -1280 N.