Advertisements
Advertisements
Question
Two toy-cars A and Bof masses 200 g and 500 g respectively are moving with the same speed. Which of the two has greater kinetic energy?
Solution
CAR A CAR B
mas= 200g mass = 500 g
=`200/1000`=`1/5` kg =`500/1000`=0.5 kg
=0.2kg
K.E.=`1/2` M`V^2` ∴ speed of both cars
is same
K.E. =`1/2`× 0.2 ×`V^2` K.E. of B=`1/2` ×0.5× `V^2`
=0.1 `v^2` =0.25 `v^2`
0.25 `v^2` is greater than 0.1`v2`
∴ K.E. of car B is greater.
Or
Since speed of both cars is same
∴ The speed of car having greater mass (i.e. of car B), the K.E. is greater
∴ Kinetic energy of car B having greater mass is greater.
APPEARS IN
RELATED QUESTIONS
A freely falling object eventually stops on reaching the ground. What happens to its kinetic energy?
Write the expression for the kinetic energy of a body explaining the meaning of the symbols used.
When an arrow is shot from a bow, it has kinetic energy in it. Explain briefly from where does it get its kinetic energy?
The kinetic energy of a body is the energy by virtue of its ______.
Two bodies of equal masses are moving with uniform velocities v and 2v. Find the ratio of their kinetic energies.
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.
By how much will the kinetic energy of a body increase if its speed is doubled?
Which of the following does not posses the ability to do work not because of motion?
An apple falling from a tree is an example for kinetic energy.
A ball of mass 0.5 kg slows down from a speed of 10 m s-1 to that of 6 m s-1. Calculate the change in the kinetic energy of the ball.
