Question

The kinetic energy of an object of mass m moving with a velocity of 5m/s is 25J What will be its kinetic energy when its velocity is increased three times?

Answer 1

Let the mass be m
v = 5m/s
K.E = 25 J
K.E = 1/2 mv^2
25 = 1/2 m (5)^2
25 x 2 = 25m
m = 2 kg
Now if the velocity becomes 3 times then the velocity is 3 x 5 = 15m/S
Now new K.E = 1/2 x 2 x 15^2
= 225 J

Answer 2

Answer:

The kinetic energy of the ball when its velocity is increased three times will be 225J.

Explanation:

Given:

Mass of the object=m

Velocity(v)=5m/s

Kinetic energy(K.E)=25J

To find: New kinetic energy=?

Solution:

We know that

$KE=\frac{1}{2}mv^{2}$

Therefore, $\frac{KE_{1} }{KE_{2} }=\frac{v_{1}^{2} }{v_{2^{2} } }$

As per the new condition, v₂=3v₁

$\frac{KE_{1} }{KE_{2} }=\frac{v_{1}^{2} }{3v_{1^{2} } }$

$\frac{25}{KE_{2} }=\frac{1}{3^{2} }$

∴K.E₂=9*25=225

Therefore, the kinetic energy of the ball when its velocity is increased three times will be 225J.