EASY
9th CBSE
IMPORTANT
Earn 100

Calculate the change that should be affected in the velocity of a body to maintain the same kinetic energy, if the mass of the body is increased to four times.

Important Questions on Work, Energy & Power

EASY
9th CBSE
IMPORTANT
A certain force acts on a body of mass 10 kg and changes its velocity from 2 m s-1 to 5 m s-1. Calculate the work done by the force.
EASY
9th CBSE
IMPORTANT
Calculate the energy possessed by a stone of mass 20 g kept at a height of 5 m. (Given g = 9.8 m s-2)
EASY
9th CBSE
IMPORTANT
An engine supplies 196 J of energy. If the energy is supplied to the weight of 500 g, how high can it be lifted? (Given g=10 m s-2)
EASY
9th CBSE
IMPORTANT
If 192×102 J of energy were used to raise a 20 kg boy above the ground, how high would he be raised? (Given, g=9.8 ms-2)
EASY
9th CBSE
IMPORTANT
A bag of rice weighs 75 kg. Calculate the height to which it should be raised so that its potential energy is 7500 J. (Given, g=10 ms-2)
EASY
9th CBSE
IMPORTANT
An electric bulb consumes 3600 J of energy in one minute. Calculate its power.
EASY
9th CBSE
IMPORTANT
If the heart works 60 J in one minute. What is its power?
MEDIUM
9th CBSE
IMPORTANT
Water is falling on the blades of a turbine at a rate of 6 × 103 kg per minute. The height of the fall is 10 m. Calculate the power given to the turbine. (Given, g=10 ms-2)