Newton's First Law

Force

A push or a pull

Net Force

The combination of all forces acting on an object

Newton's First Law

An object at rest will remain at rest and an object in motion will remain in motion unless acted upon by an unbalanced force.

Inertia

Resistance of an object to a change in its motion

Inertia is based on

mass

Vector

a quantity that has both size and direction

matter

Anything that has mass and takes up space

mass

A measure of how much matter is in an object

gravity

the force of attraction between any two objects that depends on the masses of the objects and the distance between them.

weight

A measure of the force of gravity on an object.

If I went to the moon, my _________ WILL CHANGE

weight

If I went to the moon, my ________ WILL NOT CHANGE

mass

Mass does not change because

no matter where you travel, you will always take up the same amount of space

Weight does change because

it depends on gravity which will change with smaller masses, such as the moon.

balanced force

Forces on an object that do not change the motion of the object

unbalanced force

Forces that do not cancel each other out and that cause an object to change its motion.

Balanced forces cause

1. no motion

2. constant motion

Unbalanced forces cause

1. acceleration (a change in motion)

Friction

A force that resists motion between two surfaces that are in contact.

Why doesn't the statement, "an object in motion will remain in motion" ever demonstrate itself on Earth

Because on Earth there are always going to be unbalanced forces that act on objects to slow them down to a stop. The two biggies are friction and gravity

Newton's laws of motion were based on thought experiments by

Galileo

The moon is approximately __________ the size of the Earth

1/6th - which is why you would weigh 1/6 of the amount you do on Earth. ex. a 120 lb person on Earth, would weigh 20 lbs on the Moon.