Question

Find the velocity of a body of mass 100g having a kinetic energy of 80 joule ​

Answer 1

Answer :

›»› The velocity of a body is 40 m/s.

Explanation :

Given :

• Mass of a body = 100 g.
• Kinetic energy of a body = 80 Joules.

To Find :

• Velocity of a body = ?

Solution :

To find the velocity of a body, first we will convert the unit of mass of a body from gram to kilogram.

Converting the unit of mass from gram to kilogram :

→ 100/1000

→ 0.1 kg.

We know that, if we are given with the mass of a body and kinetic energy of a body then we have the required formula, that is,

→ KE = 1/2 mv².

Here,

• KE is the Kinetic energy of a body
• m is the Mass of a body
• v is the Velocity of a body.

Substituting the given values in the formula, we get :

→ 80 = 1/2 × 0.1 × v²

→ 80 × 2 = 1 × 0.1 × v²

→ 160 = 1 × 0.1 × v²

→ 160 = 0.1 × v²

→ 160/0.1 = v²

→ 1600 = v²

→ v = √1600

→ v = 40

Hence, the velocity of a body is 40 m/s.

Answer 2

Answer:

Given :-

• Mass of body (M) = 100 g
• Kinetic energy (KE) = 80 J

To Find :-

Velocity

Solution :-

As we know that

$\huge \bf \: KE = \frac{1}{2} \times {mv}^{2}$

Here,

KE = Kinetic energy

M = Mass

V = Velocity

Let's convert mass into kg

1 kg = 1000 g

100 g = 100/1000 = 0.1 kh

$\sf \: 80 = \dfrac{1}{2} \times 0.1 \times {v}^{2}$

$\sf \: 80 \times 2 = 1 \times 0.1 \times {v}^{2}$

$\sf \: 160 = 0.1 \: v {}^{2}$

$\sf \: v {}^{2} = \dfrac{160}{0.1}$

$\sf \: v {}^{2} = 1600$

$\sf \: v = \sqrt{1600}$

$\sf \: v = 40 \: mps$

Hence

The velocity of body is 40 m/s.