Advertisements
Advertisements
Question
If the speed of a car is halved, how does its kinetic energy change?
Advertisements
Solution
K.E = `1/2 mv^2`
when `v_1 = 1/2 v`
∴ K.E. = `1/2 mv_1^2`
= `1/2 m (1/2 V)^2`
= `1/2 m v^2 (1/4)`
new K.E = `1/4 K.E`
∴ K.E changes to `1/4 th`
APPEARS IN
RELATED QUESTIONS
Calculate the work required to be done to stop a car of 1500 kg moving at a velocity of 60 km/h?
When a boy doubles his speed, his kinetic energy becomes
A bullet of mass 50 g is moving with a velocity of 500 m s−1. It penetrated 10 cm into a still target and comes to rest. Calculate:
- the kinetic energy possessed by the bullet, and
- the average retarding force offered by the target.
A body of mass 60 kg has the momentum 3000 kg m s-1. Calculate:
- the kinetic energy.
- the speed of the body.
Two bodies have masses in the ratio 5 : 1 and their kinetic energies are in the ratio 125 : 9. Calculate the ratio of their velocities.
Find the momentum of a body of mass 100 g having a kinetic energy of 20 J.
A horse and a dog are running with the same speed. If the weight of the horse is ten times that of the dog, What is the ration of their kinetic energies?
When a ball is thrown inside a moving bus, does its kinetic energy depend on the speed of the bus? Explain.
A bullet of mass 15 g has a speed of 400 m/s. What is its kinetic energy? If the bullet strikes a thick target and is brought to rest in 2 cm, calculate the average net force acting on the bullet. What happens to the kinetic energy originally in the bullet?
When a bell fixed on a cycle rings, then the energy conversion that takes place is ______.
