Question

When the speed of a moving car is tripled, how much more kinetic energy does it have?

Answer 1

`(1)/(2) m 8 v^(2)`

Step-by-step explanation:

Let initial mass of the moving car is m it is moving with the speed of v m/s.

Thus, Kinetic energy of the car is given by,

Initial Kinetic energy =
`(1)/(2) m v^(2)`

Now the velocity of moving car is changed to 3v where as its mass remains the same.

Thus, Kinetic energy of the car is given by,

Final Kinetic energy =
`(1)/(2) m (3v)^(2)`

Final Kinetic energy =
`(1)/(2) m 9 v^(2)`

The change in kinetic energy is given by,

Change in kinetic energy

= Final kinetic energy - initial kinetic energy

=
`(1)/(2) m 9 v^(2)`-
`(1)/(2) m v^(2)`

=
`(1)/(2) m 8 v^(2)`

Thus, when the speed of a moving car is tripled, kinetic energy is

`(1)/(2) m 8 v^(2)`