Question Text
Question 2 :
The gravitational potential energy of an object at a point above the ground is defined as the work done in raising it from the ground to that point against gravity.
Question 4 :
An electric heater is rated 1500 W. How much energy does it use in 10 hours?
Question 6 :
An object of mass 12 kg is at a certain height above the ground. If the potential energy of the object is 480 J, find the height at which the object is with respect to the ground. Given, g = 10 m $s^{-2}$.
Question 8 :
The kinetic energy of an object of mass m moving with a velocity of 5 $\frac{m}{s}$ is 25 J. What will be its kinetic energy when its velocity is doubled?
Question 9 :
A girl is carrying a school bag of 3 kg mass on her back and moves 200 m on a levelled road. The work done against the gravitational force will be ($g=10 ms^{-2}$)
Question 10 :
What is the work done by the force of gravity on a satellite moving round the earth?