# What will be the momentum of an object of mass 4 kg and kinetic energy 8 J?

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What will be the momentum of an object of mass 4 kg and kinetic energy 8 J?
1. 64 Kg-m/s
2. 8 Kg-m/s
3. 2 Kg-m/s
4. 4 Kg-m/s

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Correct Answer - Option 2 : 8 Kg-m/s

CONCEPT:

• Momentum: A property of a body in motion that is equal to the product of the body's mass and velocity is called momentum.

P = mv

where P is the momentum of the body, m is the mass of the body, and v is the velocity of the body.

• Kinetic energy: The energy in a body due to its motion, is known as kinetic energy.

The kinetic energy in terms of momentum is given by:

$K=\frac{P^2}{2m}$

where K is the kinetic energy of the body, P is the momentum of the body and m is the mass of the body.

CALCULATION:

Given that the Kinetic energy of the body = 8 J, m = 4 kg

$K=\frac{P^2}{2m}$

$8=\frac{P^2}{2 \times 4}$

P = 8 Kg-m/s

So the correct answer is option 2.