Which quantity is always conserved in an elastic collision?

Which statement best defines an elastic collision?

In a one-dimensional elastic collision, the relative speed of approach is:

Two identical balls collide elastically. One is initially at rest. What happens after collision?

A collision is elastic if:

If kinetic energy decreases after collision, the collision is:

Which physical quantity can change for each individual object during an elastic collision?

Two identical balls approach each other with equal speeds and collide elastically. After collision they:

During an elastic collision, the force between colliding bodies is:

Which law guarantees conservation of momentum during collision?

A moving ball collides elastically with a wall. If the speed before collision is $\mathbf{8\ m/s}$, its speed after collision is:

In an elastic collision, kinetic energy is conserved because:

Relative speed of approach is calculated using:

If two bodies move toward each other with speeds $\mathbf{6\ m/s}$ and $\mathbf{4\ }\mathbf{m/s}$, the relative speed of approach is:

Which statement best summarizes elastic collisions?

Which graph best represents total kinetic energy before and after an elastic collision?

Two equal masses collide elastically head-on. One moves at $\mathbf{5\ m/s}$ while the other is at rest. After collision, the first mass has speed:

In an elastic collision between unequal masses, which quantity remains unchanged for the system?

Why do billiard balls approximately undergo elastic collisions?

Which collision is closest to perfectly elastic?

If total momentum is conserved but kinetic energy is not, the collision is:

During an elastic collision, kinetic energy may temporarily:

A $\mathbf{2\ kg}$ object moving at $\mathbf{4\ m/s}$ collides elastically with a stationary object of equal mass. The speed of the second object after collision is:

Which statement is FALSE for an elastic collision?

Two objects move in the same direction with speeds $\mathbf{10\ m/s}$ and $\mathbf{4\ m/s}$ before collision. Their relative speed of approach is:

If the relative speed of separation is less than the relative speed of approach, the collision is:

In a perfectly elastic collision, coefficient of restitution is:

Which conservation law alone cannot determine whether a collision is elastic?

Two bodies collide elastically. Which quantity may change sign after collision?

When a rubber ball rebounds nearly to its original height, the collision is approximately:

If a moving object strikes a massive stationary wall elastically, the wall’s speed after collision is approximately:

Which pair of quantities must be checked to confirm a collision is elastic?

Two identical carts move toward each other at $\mathbf{3\ m/s}$ each and collide elastically. After collision, the speed of each cart is:

Which statement explains why kinetic energy is conserved in elastic collisions?

The relation $\mathbf{v}_{\mathbf{1}}\mathbf{-}\mathbf{v}_{\mathbf{2}}\mathbf{= - \ (}\mathbf{u}_{\mathbf{1}}\mathbf{-}\mathbf{u}_{\mathbf{2}}\mathbf{)}$ represents: