Collisions

A force can only make a moving object speed up.

A force can make a resting object move and speed up.

A force has no effect on objects at rest.

A force can only change the direction of a moving object.

When two objects come into contact with each other

When an object moves in a straight line

When two objects repel each other

When an object is at rest

An equal and opposite force on the skateboarder’s foot

No force at all

A force in the same direction as the push

A force that slows the skateboarder down

A bird flying by pushing air downward

A car accelerating on a road

A person sitting quietly

A skateboarder pushing against the ground

An object will maintain its state of motion unless a net force is exerted on it.

An object will always move unless stopped by friction.

An object will accelerate if it is at rest.

An object will stop moving if no force is applied.

Its velocity changes.

It disappears.

It remains at rest forever.

It loses mass.

To accelerate a heavier object equally, more force is needed.

Force equals mass times acceleration.

A lighter object requires more force to accelerate than a heavier object.

If two objects are accelerated equally, the one with greater mass needs more force.

0.1 m/s²

0.2 m/s²

0.5 m/s²

2 m/s²

Objects keep their shape after the collision.

Objects change shape or stick together after the collision.

Objects bounce off each other without any deformation.

Objects move in opposite directions after the collision.

Elastic collisions: objects keep their shape.

Inelastic collisions: objects stick together.

Elastic collisions: objects change shape permanently.

Inelastic collisions: objects bounce off each other without sticking.

A force can only affect objects that are moving.

A force can make a resting object move and a moving object change its speed or direction.

A force has no effect on objects at rest.

A force can only slow down objects.