Question

The kinetic energy of an object of mass, m moving with a velocity of 5 ms 1 is 25 What will be its kinetic energy when its velocity is doubled? What will be its kine energy when its velocity is increased three times.

Answer 1

Answer:-

Known Terms:-

m = Mass of the object

v  = Velocity of the object

K.E = Kinetic energy attain by object.

j = Joule.

Given:-

Kinetic energy attain by object, K.E = 25 joule.

Velocity of the object, v = 5 m/s.

To Find:-

Kinetic energy when velocity in increased three times.

Solution:-

We know that K.E = $\frac{1}{2} mv^2$

⇒ K.E = $\frac{1}{2} mv^2$

⇒ 25 = $\frac{1}{2}$ m $5^2$

⇒ m = 2 kg

1st Case

If velocity is doubled

then,

velocity of the object = 10 m/s

mass os the object = 2 kg

⇒ K.E = $\frac{1}{2} mv^2$

⇒ K.E = $\frac{1}{2}$ 2 × 10²

⇒ K.E = 100 joule.

2nd Case

If velocity is three times

Then,

velocity of the object = 15 m/s

mass os the object = 2 kg

⇒ K.E = $\frac{1}{2} mv^2$

⇒ K.E = $\frac{1}{2}$ 2 × 15²

⇒ K.E = 225 joule.

Hence, kinetic energy  when its velocity is increased three times 225 J.