Advertisements
Advertisements
Question
A car is moving with a speed of 15 km h-1 and another identical car is moving with a speed of 30 km h-1. Compare their kinetic energy.
Solution
Two identical cars mean, they have equal mass
K.E = 1/2 mv2
Let m be the mass of each car
Kinetic energy of car A = `1/2` m × `(15)^2` = `225/2` m
= 112.5 m J
Kinetic energy of car B = 1/2 M (30)2
=450 M J
`(K.E. of A) /(K.E. of B)` = `(225 m )/(2 × 450 m )` = `1/4` = 1 : 4
K.E. of car B is 4 times K.E. of car A.
APPEARS IN
RELATED QUESTIONS
An object of mass, m is moving with a constant velocity, v. How much work should be done on the object in order to bring the object to rest?
When an arrow is shot from a bow, it has kinetic energy in it. Explain briefly from where does it get its kinetic energy?
Two bodies of equal masses are moving with uniform velocities v and 2v. Find the ratio of their kinetic energies.
A cannon ball of mass 500 g is fired with a speed of 15 m s-1. Find:
- its kinetic energy.
- its momentum.
Two bodies have masses in the ratio 5 : 1 and their kinetic energies are in the ratio 125 : 9. Calculate the ratio of their velocities.
If the speed of a body is halved, what will be the change in its kinetic energy?
What is the kinetic energy of a body of mass 1 kg moving with a speed of 2 m/s?
A ball of mass 200 g falls from a height of 5 metres. What is its kinetic energy when it just reaches the ground? (g = 9.8 m/s2)
Explain the difference between potential energy and kinetic energy.
Find out the form of energy possessed by the following thing.
A rolling ball
