Unit 2 Physical Science Review

formula for momentum

p=mv

What does conservation of momentum mean

If 2 objects collide, the momentum before the collision is equal to the momentum after the collision

What is the formula for the conservation of momentum

m1v1 + m2v2 = m1v1 +m2v2

How is force defined?

A push or a pull

What is net force

The sum of all forces acting on an object

If the net force is zero

The forces are balanced and the object is at rest

If the net force IS NOT zero

The forces are unbalanced and the object is accelerating

What is the result of balance forces on an object

object is either not moving or moving with constant velocity

What is the result of an unbalanced force on an object

the object is accelerating

State the metric unit for force with its abbreviation.

Newton (N)

Net force formula

F=ma

Static friction

occurs when objects are in contact but not moving

Sliding friction

occurs when objects are in contact and sliding

Rolling friction

occurs when objects are in contact and rolling (such as wheels)

How would you recognize an unbalanced force acting on an object?

the object would be accelerating

How would you recognize a balanced force acting on an object?

the object is either moving or not moving with a constant velocity

Types of free body diagram forces

gravity, normal, friction, applied, air resistance, tension or spring

What is weight

the gravitational force exerted on an object

Formula for weight

W=mg

How is weight different from mass

Mass is the amount of matter in an object, weight depends on mass and gravity

Value for Earth's gravitational strength

9.8m/s^2

Newton's First Law

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.

If the forces on an object are balanced, what does it say about the motion of the object

It will remain at rest until an unbalanced force acts on it

What is interia

The tendency of an object to resist a change in motion

Do all objects have inertia?

Yes

How does the mass of the object affect its inertia?

Greater the mass, the greater the inertia

Do all objects resist changes in motion

Yes

Briefly explain how inertia works by passenger in a car

The car is traveling down the road at 50 mph, and the passengers are moving at the same speed. If it stops suddenly, the people will continue to fly forward until acted upon by an outside force, like a seatbelt

Netwon's second law

The unbalanced force acting on an object is equal to the object's mass times its acceleration (F=ma)

Does the 2nd law deal with balanced or unbalanced forces? Or both?

Unbalanced forces

According to the 2nd law, if I apply a force on an object what should it do

The mass won't change, but the object will accelerate

Newton's Third Law

For every action there is an equal and opposite reaction

4 facts about the 3rd law

1. Forces act in pairs
2. Forces are the same size but in opposite directions
3. Forces do not act on the same object
4. Forces occur at the same time