Advertisements
Advertisements
प्रश्न
Calculate the work required to be done to stop a car of 1500 kg moving at a velocity of 60 km/h?
Advertisements
उत्तर
Here, the mass of the car, m = 1500 kg
The initial velocity of the car, u = 60 km h-1
= `(60 xx 1000 m)/(60 xx 60 s)`
= `50/3 ms^-1`
The initial kinetic energy of the car,
`K.E_i = 1/2 "mu"^2`
= `1/2 (1500 kg) (50/3 ms^-1)^2`
= 208333.3 J
Final kinetic energy of the car,
`K.E_f = 1/2 mv^2`
= 0
Change in kinetic energy of the car
= K.Ef - K.Ei
= - 208333.3 J
The minus sign indicates the work is being done against the moving car.
APPEARS IN
संबंधित प्रश्न
A freely falling object eventually stops on reaching the ground. What happens to its kinetic energy?
Write the expression for the kinetic energy of a body explaining the meaning of the symbols used.
Give reasons for the following A horse and a dog are running with the same speed. Which one of them has more kinetic energy than the other.
A body is thrown vertically upwards. Its velocity keeps on decreasing. What happens to its kinetic energy as its velocity becomes zero?
By how much will the kinetic energy of a body increase if its speed is doubled?
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?
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?
The kinetic energy of a body of mass 4 kg and momentum 6 Ns will be
If the mass as well as the velocity of a body is doubled then the kinetic energy of the body ______ the initial kinetic energy.
