Newton's laws of motion

Which statement best describes Newton's third law?

For every force one object exerts on another, the second exerts an equal and opposite force on the first

One newton is equivalent to which combination of SI base units?

1 kg·m/s²

A book rests on a horizontal table. Which two forces balance on the book?

Its weight downward and the table's normal force upward

What does Newton's first law state?

An object remains at rest or moves with constant velocity unless acted on by a nonzero net external force

For an object of constant mass, which equation expresses Newton's second law?

F_net = ma

What motion is possible when the net force on an object is zero?

Rest or motion with constant velocity

Why do the two forces in a Newton's third-law pair not cancel each other?

They act on different objects

What is the SI unit of force?

Newton

Which expression gives the weight of an object near Earth's surface?

W = mg

Which quantity is a measure of an object's inertia?

Mass

Several forces act on an object. What is the net force?

The vector sum of all the forces

A car travels around a circular track at constant speed. Why is it accelerating?

Its direction of velocity is changing

In mechanics, what is inertia?

The tendency of an object to resist changes in its velocity

What determines the direction of an object's acceleration?

The direction of the net force

A constant net force acts on an object. What happens to its acceleration if its mass is doubled?

It is halved

A swimmer pushes water backward. Which interaction moves the swimmer forward?

The water exerts a forward force on the swimmer

A box is pushed to the right with 30 N while friction acts to the left with 10 N. What is the net horizontal force?

20 N to the right

A net force of 12 N acts on a 3 kg object. What is the object's acceleration?

4 m/s²