Question

. Find the momentum of a body of mass 100 g having kinetic energy 500 J.

Answer 1

Answer

• Momentum of the body = 100 kg m/s

Explanation

Given

• Mass of the body = 100 g
• Kinetic energy of the body = 550 J

Knowledge required ::

• Formula to calculate kinetic energy :-

⠀⠀⠀ KE = 1/2 mv²

• Formula to calculate momentum :-

⠀⠀⠀ p = mv

where,

• m = mass of the body
• v = velocity of the body
• p = momentum of the body

~Understanding the concept ::

Here we have to find the momentum of the body. Firstly, we will find the velocity of the body by using the formula of kinetic energy. Then substitute the value of mass and velocity in the formula of momentum to find its value.

Solution

Mass of the body = 100 g

As we know,

1 g = 1/1000 kg

Divide the value by 1000 to convert it from g into kg.

⇒ Mass = 100 g = 100/1000 = 1/10 = 0.1 kg

Mass of the body = 0.1 kg

⠀⠀⠀⇒ KE = 1/2 mv²

⠀⠀⠀⇒ 500 = 1/2 × 0.1 × v²

⠀⠀⠀⇒ 500 = 1/2 × 1/10 × v²

⠀⠀⠀⇒ 500 = 1/20 × v²

⠀⠀⠀⇒ 500 × 20 = v²

⠀⠀⠀⇒ 10000 = v²

⠀⠀⠀⇒ √10000 = v²

⠀⠀⠀⇒ 100 = v

Velocity of the body = 100 m/s

Momentum of the body :-

⠀⠀⠀⇒ p = mv

⠀⠀⠀⇒ p = 0.1 × 100

⠀⠀⠀⇒ p = 1/10 × 100

⠀⠀⠀⇒ p = 100

Momentum of the body = 100 kg m/s