Question

Two unequal masses possess the same momentum, then the kinetic energy of the heavier mass is _________ the kinetic energy of the lighter mass.

• A. same as
• B. greater than
• C. less than
• D. cannot say

Answer 1

The correct option is C less than

Kinetic energy is given by K.E = $\frac{1}{2}$mv${}^2$

Momentum is defined as P = mv

Thus K.E = $\frac{1}{2}$Pv${}^2$

P1 = M(greater mass) $\ast$ v

P2 = m $\ast$ v(greater velocity)

P2 = P1 = P

K1 = $\frac{1}{2}$Pv

K2 = $\frac{1}{2}$PV

SInce V>v, K2>K1

Therefore the kinetic energy of the heavier mass is less than the kinetic energy of the lighter mass.