Newton's First Law Flashcards

All 6 cards in this deck

State Newton's first law.

A body stays at rest or moves at constant velocity unless acted on by a resultant force.

What is the resultant force on a body moving at constant velocity?

Zero — the forces on it are balanced.

What happens to a body when the resultant force on it is not zero?

Its speed and/or direction changes (it accelerates).

True or false? A box at rest on a floor has its weight balanced by an equal upward force from the floor.

True. The two forces are equal in size and opposite in direction, so the resultant force is zero.

What is a resultant force?

One force that could replace all the forces acting on an object and change its motion in exactly the same way.

How do you find the resultant of forces acting along a straight line?

Choose one direction as positive, count forces in the opposite direction as negative, then add them all together.