Question

c)The kinetic energy of an object of mass, m moving with a velocity of 4 m/s is 40 J. What doubled?​

Answer 1

Explanation:

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

2

1

mv

2

⇒ K.E = \frac{1}{2} mv^2

2

1

mv

2

⇒ 25 = \frac{1}{2}

2

1

m 5^25

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

2

1

mv

2

⇒ K.E = \frac{1}{2}

2

1

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

2

1

mv

2

⇒ K.E = \frac{1}{2}

2

1

2 × 15²

⇒ K.E = 225 joule.

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