Which type of energy is stored while stretching the catapult? How this energy is obtained?
While stretching the catapult, potential energy is stored in it. This energy is obtained by doing work against the restoring force of the string.
A car of mass 1500 kg is moving with the speed of 72km/hr. calculate its kinetic energy.
Solution:
Given,
mass of car (m) = 1500 kg
velocity of car (v) = 72 km/hr = 72 * 1000/3600 (m/s) = 20 m/s
To find: Kinetic Energy of car (KE) = ?
We know,
KE = 1/2 m(v)2
= 1/2 (1500) (20)2
= 300 000 J
= 3 x 106 J
Hence, the required Kinetic Energy of the car is 3 x 106 J.