Newton's Laws Review

Law of Inertia

Newton's 1st Law - An object in motion stays in motion and an object at rest stays at rest unless acted on by an unbalanced force. Ex. When a car stops quickly, everything in the car flies forward.

Law of Force and Acceleration

Newton's 2nd Law - F =mass x acceleration. Use Force Triangle (force on top). Ex. An object with a greater mass accelerates less than an object with less mass.

Law of Action-Reaction

Newton's 3rd Law - For every action, there is an equal but opposite reaction. Ex. Action - A book pushes down on a desk. Reaction - Desk pushes up on book.

Gravity

Things accelerate to Earth at a rate of 9.8m/s2. Gravity is an acceleration and acts on every object on Earth.

Friction

Force that works against motion.

Acceleration

Change in speed and direction (change in velocity)

Velocity

Speed and direction

Force

A push or pull

Weight

Mass x gravity; measure of the pull of gravity on an object that has mass

Mass

Amount of matter an object contains

Inertia

An objects tendency to resist motion.

Which object has more inertia: tennis ball or refrigerator?

Refrigerator

A box is pushed to the right with a 10N force and to the left with a 2N force. Which direction is the net force?

Net force of 8N to the right.

Newton (N)

Measure of force - 1 Newton is equal to 1 kg.m/s2

Which would have a greater acceleration when a 10 N force is applied: a 2 gram toy truck or a 5 gram toy truck?

A 2 gram truck - using Newton's 2nd Law and F=ma