Question

There are no external force acting during collision of two object then which of the following statement is true?

• A. The total momentum before the collision is always equal to the total momentum after the collision.
• B. Both momentum and kinetic energy are conserved in the collision
• C. The two objects must stick together
• D. The speed of each object must remain the same before and after the collision.
• E. The momentum of each object must remain the same before and after the collision

Answer 1

Answer: (A)

The total momentum before the collision is always equal to the total momentum after the collision.

Given : $F_{ext}=0$

$\therefore$ $\frac{dP}{dt}=F_{ext}=0$ $⟹P=$constant

Thus total linear momentum of the system is conserved i.e total momentum before the collision is always equal to the total momentum after the collision.