An airbag reduces the force on a passenger in a crash because it

increases the time over which the momentum changes

Which force does no work on an object?

A force perpendicular to the motion

It is converted to internal (thermal) energy

Its velocity direction is constantly changing

Friction between the tyres and the road

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

A $4.0$ kg object moves at $5.0$ m/s. What is its momentum?
An airbag reduces the force on a passenger in a crash because it
In an isolated system, which quantity is conserved in every collision?
A $2.0$ kg cart moving at $6.0$ m/s collides with a stationary $4.0$ kg cart and they stick together. What is their common velocity?
A $30.$ N force moves a box $4.0$ m in the direction of the force. How much work is done?
Which force does no work on an object?
A $2.0$ kg object moves at $4.0$ m/s. What is its kinetic energy?
A box slides to a stop on a rough floor. What happens to its kinetic energy?
Why is an object moving at constant speed in a circle accelerating?
A car rounds a flat curve at constant speed. What supplies the centripetal force?
A $0.50$ kg ball moves in a circle of radius $2.0$ m at $4.0$ m/s. What is the centripetal force?
If the distance between two masses is tripled, the gravitational force between them becomes