Advertisements
Advertisements
प्रश्न
An object of mass, m is moving with a constant velocity, v. How much work should be done on the object in order to bring the object to rest?
Advertisements
उत्तर
Mass of the object = m
The initial velocity of the object = v,
The final velocity of the object = 0
Work done on the object = Change in kinetic energy of the object = Final kinetic energy − Initial kinetic energy
= `1/2 M xx (0) - 1/2 m . v^2`
= `(0) - 1/2 m . v^2`
= `-1/2 m . v^2`
The negative sign shows that the work done is opposite to the object's direction of motion.
APPEARS IN
संबंधित प्रश्न
The kinetic energy of an object of mass m moving with a velocity of 5 m s−1 is 25 J. What will be its kinetic energy when its velocity is doubled? What will be its kinetic energy when its velocity is increased three times?
An object of mass 40 kg is raised to a height of 5 m above the ground. What is its potential energy? If the object is allowed to fall, find its kinetic energy when it is half-way down.
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.
How much work is needed to be done on a ball of mass 50 g to give it a momentum of 5 kg cm s-1?
How fast should a man of 50 kg run so that his kinetic energy be 625 J?
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?
An apple falling from a tree is an example for kinetic energy.
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:
Find the kinetic energy of a body of mass 5 kg moving with a uniform velocity of 10 m s-1.
