Work And Energy...

Which of the following is the biggest unit of energy?

A person carrying a load of 50 kg on his head moves 10 m on a straight horizontal road. The amount of work done by him is

A truck and a car are moving on a smooth, level road such that the kinetic energy associated with them is the same. Brakes are applied simultaneously in both of them such that equal retarding forces are produced in both. Which one will cover greater distance before it stops?

The work done in lifting 1 kg mass to a height of 9.8 m is about

The kinetic energy of a body becomes four times its initial value while travelling along a straight line. The new momentum will be

The figure below shows a body of mass 10 kg sliding from rest, down a frictionless track of radius R (in m). Assume that the body started from the top of the track P and slides to the bottom Q. The change in the gravitational potential energy in the motion is (g = acceleration due to gravity)

The earth's radius is R and acceleration due to gravity at its surface is g. If a body of mass m is sent to a height h = R/6 from the earth's surface, the potential energy (PE) increases by

A rifle bullet loses of its velocity in passing through a plank. What is the least number of such planks required just to stop the bullet?

A particle of mass m is taken along different frictionless paths AB as indicated by the following diagrams. In each case, the particle starts from rest at A and reaches point B. All the paths are in a vertical plane and the external forces act such that the particle moves along the respective paths without restraint.



Which of the following statements will be true in respect of the given diagrams?

An object of mass 20 kg falls from rest through a vertical distance of 10 m and acquires a velocity of 10 m/s. The work done by the push of air on the object is (g = 10 m/s²)

In an inclined plane, we lose in terms of distance but gain in terms of

Which of the following options is not a unit of power?

An electric motor creates a tension of 9,000 newton in a hoisting cable and reels it in at the rate of 2 m/s. What is the power of this motor?

A man weighing 60 kg lifts a body of 15 kg to the top of a building10 m high in 3 minutes. His efficiency is

A body is moved along a straight line by a machine delivering constant power. The distance moved by the body in time t is proportional to

Heat energy is converted into electrical energy by using a

Which of the following options converts light energy into electrical energy?

A bent bow used for shooting an arrow possesses

A spring of force constant 60 N/m has an initial stretch 0.2 m. In changing the stretch to 0.25 m, the increase in P.E. is about

It requires twenty turns of the stem of a watch to wind the main spring and this stores sufficient energy to keep the watch running for 30.0 hours. If ten turns are given to the stem, it will be