Work And Energy...

One kWh is equal to

A body covers a distance of 10 m along a straight line under the action of a force of 5 N. If the work done is 25 J, then the angle that the force makes with the direction of motion of the body is

The graph given below represents the relation between displacement x and force F. The work done in displacing an object from x = 8 m to x = 14 m is (approximately)

If the momentum of a body increases by 20%, then percentage increase in kinetic energy is

Two bodies of mass 2m and 3m are approaching each other at velocities 4v and 5v, respectively. After a while, their velocities become 6v and 7v, respectively. What is the total change in kinetic energy?

Two bodies of equal weights are kept at heights h and 1.5 h respectively. The ratio of their potential energy is

Two bodies of masses m_A and m_B have equal KE. The ratio of their momenta is

A truck and a car moving with the same K.E. are brought to rest by the application of brakes which provides equal retarding forces. Which of them will come to rest in a shorter distance?

A body falls freely under gravity from height h. Its gravitational potential energy and kinetic energy vs time graph are shown in the figure. The correct variation is represented by

The PE of a simple pendulum is the highest, when it is

Which of the following devices does not come under the category of lever?

Find the mechanical advantage of a machine, which has a velocity ratio as 3.2 and efficiency as 75%.

Water at Bhakra Dam is falling through 200 m. What will be the amount of energy available from the fall of 40 metric tonnes of water? (g = 10 m/s²)

Scalar product of force with velocity is called

A vehicle needs an engine of 7500 watts to keep it moving with a constant velocity of 30 m/s on a horizontal surface. The force resisting the motion is

The temperature of water at the bottom of a waterfall is higher than that of the water at the top because

Sound energy is converted into electrical energy in a

When a spring is wound, a certain amount of PE is stored in it. If this wound spring is dissolved in acid, the stored energy

The spring of the winding knob of a watch has

The PE stored in a long spring stretched by x cm is U. If the spring is stretched by 4x cm, its PE will be