Question

plz answer this plzzzz​

Answer 1

a vehicle of 1 tonne travelling with a speed of 60m/s notices a cow on the road 9 m ahead applies brakes. it stops just in front of the cow .

1.find out the kinetic energy of the vehicle before applying brakes

2. calculate the retarding force provided by the brakes.

• So kinetic energy before applying brake will be.

• K.E = 1/2 mv^2

• = 1/2 × 10^3 × 60^2

• = 1/8 × 10^6 J

• We know that from equation of motion we get

• So v^2 = u^2 + 2as

• 0 = 60^2 + 2a(9)

• 0 = 3600 + 18a

• Or a = -200m/s^2

• Now regarding Force F = ma

• = 10^3 × 200

• Or Force F = 2 × 10^5 N