If the velocity of a body becomes two times its initial velocity, its kinetic energy becomes n times its initial kinetic energy. What is the value of n?

Question

Question

This question was previously asked in

RRB ALP Previous Paper 7 (Held On: 13 Aug 2018 Shift 2)

Answer 1

The correct answer is Option 2, i.e 4.

CONCEPT:

Kinetic energy (KE): The energy possessed by a body by virtue of its motion is called kinetic energy.

Where m = mass of the body and v = velocity of the body

CALCULATION:

Let the initial velocity be u and final velocity be v.

According to the given question, velocity becomes two times its initial velocity. This means V = 2u

Initial kinetic energy (KE) = 1/2 mu²

Final kinetic energy (KE') =1/2 mv² =1/2 m(2u)² =1/2 m × 4u² =4 × 1/2 mu²

KE' = 4 × KE, where n = 4

∴ The Kinetic energy becomes 4 times when velocity is doubled.