Newton's laws of motion help explain why an object needs a force to make it move - inertia also explains this. Momentum, on the other hand, explains some of the most important interactions in nature.

Which word describes the forces on an object moving at a constant speed?

Resultant

Balanced

Unbalanced

If a resultant force acts on an object, what happens to its motion?

There is no change in speed

The object accelerates in opposite direction to resultant force

The object accelerates in same direction as resultant force

If a submarine is moving at a constant forward speed at the same depth , what can we say about the forces acting on it?

The buoyancy force is the same size as the weight. The engine force is bigger than the water resistance.

The buoyancy force is the same size as the weight. The engine force is the same size as the water resistance.

The buoyancy force is bigger than the weight. The engine force is the same size as the water resistance.

What is the relationship between acceleration and force?

Acceleration is directly proportional to force

Acceleration is inversely proportional to force

Acceleration is not proportional to force

What is the relationship between acceleration and mass?

Acceleration is directly proportional to mass

Acceleration is inversely proportional to mass

Acceleration and mass are not proportional

A car moving at 20 m/s brakes until it reaches 5 m/s in 5 seconds. What is the value for the acceleration of the car?

5 m/s²

-3 m/s²

3 m/s²

Which of these statements about Newton's third law of motion is correct?

The forces are always contact forces

The forces act on the same object

The forces act on two different objects

Which of these pairs of forces are not a third law pair?

The weight of a book (on a table) and the contact reaction force of the table on the book

The gravitational pull of the Earth on a satellite and the gravitational pull of the satellite on the Earth

A car tyre pushing on the road and the road pushing on the tyre

What is the momentum of a 15 kg dog running at 4 m/s? - Higher

3.25 kg m/s

19 kg m/s

60 kg m/s

What does conservation of momentum mean? - Higher

Total momentum before is equal to total momentum after

Total momentum must decrease after a collision

All objects must start with some momentum