Question

A body of mass 5kg is moving with velocity 3m−1, then find its Kinetic energy

Answer 1

Answer :

➥ Kinetic energy of the body = 22.5 J

Given :

➤ Mass of the body (m) = 5 kg

➤ Velocity of the body (v) = 3 m/s

To Find :

➤ Kinetic energy of the body (K.E) = ?

Solution :

As we know that

Kinetic energy of a body

$\tt{:\implies K.E = \dfrac{1}{2}m {v}^{2}}$

$\tt{:\implies K.E = \dfrac{1}{2} \times 5 \times 3 \times 3}$

$\tt{:\implies K.E = \dfrac{1}{2} \times 15 \times 3}$

$\tt{:\implies K.E = \dfrac{1}{ \cancel{ \: 2 \: }} \times \cancel{45}}$

$\tt{:\implies K.E = 1 \times 22.5}$

$\bf{:\implies \underline{ \: \: \underline{ \purple{ \: \: K.E = 22.5 \: J \: \: }} \: \: }}$

Hence, the kinetic energy of the body is 22.5 J.

Answer 2

Given ,

Mass (m) = 5 kg

Velocity (v) = 3 m/s

We know that , the kinetic energy of a body is given by

$\boxed{ \tt{Kinetic \: energy = \frac{1}{2}m {(v)}^{2} }}$

Thus ,

Kinetic energy = 1/2 × 5 × (3)²

Kinetic energy = (5 × 9)/2

Kinetic energy = 45/2

Kinetic energy = 22.5 Joule

Hence , The kinetic energy of a body is 22.5 J