Advertisements
Advertisements
प्रश्न
Define the term 'energy' of a body. What is the SI unit of energy.
Advertisements
उत्तर
Energy is the ability to do work. The amount of energy possessed by a body is equal to the amount of work it can do when its energy is released. It is a scalar quantity as it has only magnitude.
The SI unit of energy is Joule (J).
APPEARS IN
संबंधित प्रश्न
A metal ball of mass 2 kg is allowed to fall freely from rest from a height of 5 m above the ground. Taking g = 10 m s−2, calculate:
- the potential energy possessed by the ball when it is initially at rest.
- the kinetic energy of the ball just before it hits the ground?
State whether the object possess kinetic energy, potential energy, or both :
A flying aeroplane _______________.
What kind of energy is possessed by the following?
A stone kept on roof-top _______________
What kind of energy is possessed by the following?
A running car ____________
A boy weighing 40 kg makes a high jump of 1.5 m.
What is his kinetic energy at the highest point?
Two bodies having equal masses are moving with uniform speeds of v and 2v respectively. Find the ratio of their kinetic energies.
Name the device or machine which convert :
Mechanical energy into electrical energy.
Name the device or machine which convert :
Electrical energy into sound energy.
Describe the energy changes which take place in a radio.
An automobile engine propels a 1000 kg car (A) along a levelled road at a speed of 36 km h–1. Find the power if the opposing frictional force is 100 N. Now, suppose after travelling a distance of 200 m, this car collides with another stationary car (B) of the same mass and comes to rest. Let its engine also stop at the same time. Now the car (B) starts moving on the same level road without getting its engine started. Find the speed of the car (B) just after the collision.
