U2- Laws of motion

contact force

A push or pull on an object by another object that is touching it.

force

A push or a pull on an object.

friction

Force that resists the motion of two surfaces that are touching.

gravity

Attractive force that exists between all objects that have mass.

mass

Amount of matter in an object.

noncontact force

A force one object can apply to another object without touching it; e.g. the force of gravity and the electric and magnetic forces.

static friction

Opposes motion; prevents surfaces from sliding past each other; increases as applied force increases.

sliding/kinetic friction

Opposes motion between sliding surfaces; does not increase, so increasing the applied force makes objects slide faster.

fluid friction

Occurs between a surface and materials like water and air; can result in air resistance.

weight

Gravitational force exerted on an object.

balanced forces

Combined forces form a net force of zero.

inertia

Tendency of an object to resist a change in its motion.

net force

Combination of all the forces acting on an object.

Newton's 1st Law of Motion

An object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force; also known as the Law of Inertia.

reference direction

Measured from a starting point to describe an object's position.

unbalanced forces

Combined forces that form a net force that is not zero.

centripetal force

A force in circular motion that acts perpendicular to the direction of motion toward the center of the circle.

circular motion

Any motion in which an object is moving along a curved path.

Newton's 2nd Law of Motion

Acceleration is equal to the net force exerted on the object divided by the object's mass.

velocity formula

Distance/time.

acceleration formula

(Final velocity - initial velocity) / time.

acceleration units

m/s².

Formula for Weight

W = mg.

Newton's 2nd Law of Motion formula

F = ma or a = F/m.

force pair

Forces that two objects apply to each other.

Law of Conservation of Momentum

Total momentum of a group of objects remains the same unless outside forces act on the objects.

momentum

Measure of how hard it is to stop a moving object.

momentum formula

p = mv.

momentum units

kg(m/s).

Newton's 3rd Law of Motion

For every action there is an equal and opposite reaction.

Newton

Unit of force.

1 N =

1 kg*m/s².

The Universal Law of Gravitation

All objects are attracted to each other by a gravitational force; the strength of the force depends on the mass of each object and the distance between them.

elastic collision

Colliding objects bounce off each other.

inelastic collision

Colliding objects stick together.