Question

A particle of mass 2kg is moving along a straight line. If the magnitude of its linear momentum is 2kg m/s then find its kinetic energy

Answer 1

let, the object's velocity be - v m/s

given mass= 2kg

we know,

momentum=mass × velocity

∴ 2=2v

⇒v=1

∴velocity = 1m/s

∴kinetic energy = 1/2*2*1² J   [1/2mv²]

=1 J

Answer 2

Answer:

1 joule

Explanation:

The following formulas are relevant in this question :

Kinetic energy = ½mv²

Where:

m = mass of the body

V = velocity of the body

Linear momentum = mass × velocity

Whereby mass is in kilograms and velocity is in m/s.

Now, given the mass and momentum we can get the velocity.

Velocity = momentum/mass

= 2/2 = 1 m/s

We need to get the kinetic energy :

Kinetic energy = ½mv²

Doing the substitution we have :

Kinetic energy = ½ × 2 × 1² = 1 Joule

The kinetic energy = 1 joule