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
What is the kinetic energy of an object?
A freely falling object eventually stops on reaching the ground. What happens to its kinetic energy?
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.
By how much will the kinetic energy of a body increase if its speed is doubled?
Write an expression for the kinetic energy of a body of mass m moving with a velocity v.
On what factors does the kinetic energy of a body depend?
A man drops a 10 kg rock from the top of a 5 m ladder. What is its speed just before it hits the ground? What is its kinetic energy when it reaches the ground? (g = 10 m/s2)
What do you understand by the kinetic energy of a body?
Which of the following does not posses the ability to do work not because of motion?
A body starts from rest and is acted on by a constant force. The ratio of kinetic energy gained by it in the first five seconds to that gained in the next five-second is:
