According to the law of conservation of momentum, when no external force acts, the total momentum after a collision is:

Equal to the total momentum before

Two cars crash and crumple together. What happens to the total momentum and the kinetic energy?

Momentum is conserved, kinetic energy is not

To keep the total momentum (initially zero) conserved, the rifle gains equal and opposite momentum

It extends the time over which the person stops

Its velocity is constantly changing direction

Toward the center of the circle

Moves in a straight line tangent to the circle

12questions. Pick an answer and you'll see why right away.

What is the momentum of a $3.0$ kg object moving at $4.0$ m/s?
Impulse is a force acting over a time. What does it equal?
For the same change in momentum, how can the force on an object be reduced?
According to the law of conservation of momentum, when no external force acts, the total momentum after a collision is:
A $5.0$ kg cart at $4.0$ m/s collides with and sticks to a stationary $3.0$ kg cart. What is their common velocity?
In which type of collision is kinetic energy conserved?
Two cars crash and crumple together. What happens to the total momentum and the kinetic energy?
A rifle fires a bullet forward. Why does the rifle recoil backward?
How does an airbag reduce the force on a person in a crash?
Why is an object moving in a circle at constant speed still accelerating?
In which direction does the centripetal force on an object moving in a circle point?
A ball is whirled on a string in a horizontal circle, and the string breaks. What does the ball do?