Question

Which statement is true for an elastic collision in two dimensions?

Kinetic energy is not conserved.

Momentum is not conserved.

Only momentum is conserved.

Kinetic energy and momentum are conserved.

Answer 1

Both quantities are conserved in elastic collisions. In inelastic collisions, KE is lost to deformation energy. Last answer is right

Answer 2

Kinetic energy and momentum are conserved this statement is true for an elastic collision in two dimensions.

d is correct

Step-by-step explanation:

Elastic collision :

Elastic collision in two dimensions follows same rules as a collision in one dimension.

In elastic collision, The kinetic energy and momentum are same before and after collision it means momentum and kinetic energy are conserved.

Momentum is conserved :

Before collision and after collision

`m_(1)u_(1)+m_(2)u_(2)=m_(1)v_(1)+m_(2)v_(2)`

Kinetic energy is conserved:

Before collision and after collision

`(1)/(2)m_(1)u_(1)^(2)+(1)/(2)m_(2)u_(2)^(2)=(1)/(2)m_(2)v_(1)^(2)+(1)/(2)m_(2)v_(2)^(2)`

In inelastic collision :

In inelastic collision, The momentum is conserved but energy not conserved.

Hence, Kinetic energy and momentum are conserved this statement is true for an elastic collision in two dimensions.