Find the best tutors and institutes for Class 9 Tuition
Search in
What is the kinetic energy of an object?
Kinetic energy is the energy possessed by a body by the virtue of its motion. Every moving object possesses kinetic energy. A body uses kinetic energy to do work. Kinetic energy of hammer is used in driving a nail into a log of wood, kinetic energy of air is used to run wind mills, etc.
Write an expression for the kinetic energy of an object.
If a body of mass m is moving with a velocity v, then its kinetic energy 
is given by the expression,
Its SI unit is Joule (J).
The kinetic energy of an object of mass, m moving with a velocity of 5 m s−1 is 25 J. What will be its kinetic energy when its velocity is doubled? What will be its kinetic energy when its velocity is increased three times?
Expression for kinetic energy is 
m = Mass of the object
v = Velocity of the object = 5 m s−1
Given that kinetic energy, 
= 25 J
(i) If the velocity of an object is doubled, then v = 5 × 2 = 10 m s−1.
Therefore, its kinetic energy becomes 4 times its original value, because it is proportional to the square of the velocity. Hence, kinetic energy = 25 × 4 = 100 J.
(ii) If velocity is increased three times, then its kinetic energy becomes 9 times its original value, because it is proportional to the square of the velocity. Hence, kinetic energy = 25 × 9 = 225 J.
How helpful was it?
How can we Improve it?
Please tell us how it changed your life *
Please enter your feedback
UrbanPro.com helps you to connect with the best Class 9 Tuition in India. Post Your Requirement today and get connected.
Find best tutors for Class 9 Tuition Classes by posting a requirement.
Get started now, by booking a Free Demo Class
