Question

0.3. Find the velocity of a body of mass 100 g having a kinetic energy of 20 J.​

Answer 1

Answer:

m=100g or 0.1kg

Note:You have to convert g to kg if J is given as the derived unit of energy is kgm^2/s^2

$Since,Kinetic \: \: energy= \frac{1}{2}m {v}^{2}$

$20 = \frac{1}{2} \times 0.1 \times {v}^{2}$

$40 = 0.1 \times {v}^{2}$

${v}^{2} = \frac{40}{0.1}$

${v}^{2} = 400$

$v = \sqrt{400}$

v=20m/s

Answer 2

Given :-

Mass of the body = 100 g

Kinetic energy of the body = 20 J

To Find :-

The velocity of the body.

Analysis :-

Here we are given with the mass and the kinetic energy of the body.

In order to find the velocity, substitute the mass and the kinetic energy using the formula of kinetic energy accordingly and find the velocity.

Solution :-

We know that,

• m = Mass
• KE = Kinetic energy
• v = Velocity

Using the formula,

$\underline{\boxed{\sf Kinetic \ energy=\dfrac{1}{2} mv^2}}$

Given that,

Mass (m) = 100 g = 0.1 kg

Kinetic energy (KE) = 20 J

Substituting their values,

⇒ 20 = 1/2 × 0.1 × v²

⇒ 0.1 × v² = 20 × 2

⇒ 0.1 × v² = 40

⇒ v² = 40/0.1

⇒ v² = 400

⇒ v = √400

⇒ v = 20 m/s

Therefore, the velocity of the body is 20 m/s.