Newtons First, Second, and Third Law of Motion

What is Newton's 1st Law of Motion?

An object at rest remains at rest and an object in motion remains in motion at constant velocity unless acted upon by an unbalanced force

What is happening to an object at rest that begins moving or to an object in motion that changes speed or direction?

It's accelerating

What does inertia mean?

The tendency of things to resist change in motion

Every object ever made of matter has ___________.

Inertia

What is Newton's First Law sometimes called?

The Law of Inertia

What is Newton's 2nd Law of Motion?

The acceleration of an object is directly proportional to the net force acting on the object, is in the direction of the net force, and is inversely proportional to the mass of the object

What is the equation for Newton's Second Law of motion?

acceleration= force÷mass
a=F÷m

What does the law mean by "directly proportional"?

If "F" were doubled, "a" would also be doubled, the same if "F" was halved

What does the law mean by "inversely proportional"?

If "m" were doubled, "a" would be halved, the same if "m" were halved

What is a force?

A push or pull on an object

What are some examples of the things that can exert forces on objects?

Gravity, electricity, magnets, and muscles

What is the net force?

The sum of the forces acting on the object

How do you find the net force?

Add forces acting in the same direction and subtract the ones acting in the opposite directions

An object is going west 90 N and going east 50 N. What is the net force?

It is accelerating 40 N

What does force involve?

Magnitude (amount) and direction

Because of the things involved in force, it means that it's _ ______ ________.

A vector quantity

Scalar quantities have what?

Magnitude which is the net force that produces acceleration

What is a Newton?

The force that accelerates a mass and the equation for it is: 1N=1kg•m/s^(2)

When is an object in equilibrium?

When it's acted upon by balanced forces

What must be required to make a net force of 0?

There needs to be 2 forces that are equal in magnitude and opposite in direction

What if the net force is 0?

That means the applied forces are unbalanced and acceleration will occur but it is not equilibrium

What is inertia?

The more matter an object has, the more inertia it has

Which would be harder to change the velocity of, a moving bus or a moving bike?

A bus because it has more matter therefore it has more inertia

What is mass?

The quantity of matter in an object

What is weight?

Weight is the force upon an object caused by gravity

What is the metric unit of weight?

A Newton

What is the metric unit of mass?

A kilogram

Mass and weight are ________ ____________.

Directly Proportional

How does an intact objects mass change?

It never does

An objects weight depends on what?

The force of gravity acting upon it

How can an objects weight change?

If it leaves the surface of the Earth

What is an object's mass considered to be?

It's weight caused by the gravity on the Earth (measured by lbs)

What makes mass different from gravity?

Mass will never change regardless of gravity

What is the difference between the first and second law of motion?

The first deals with balanced forces while the second deals with unbalanced forces

If matter in an object never change, this means an objects _______ _____ _______.

Inertia never changes

Why are mass and volume not necessarily proportional?

Density

What is a static equilibrium example?

A glass at rest on a table

Why is somebody standing on the Earth's surface an example of Static equilibrium?

The person is producing a downward force on the Earth's surface whileEarth's surface is the force pushing up on the person with equal magnitude due to gravity

What is a dynamic equilibrium example?

Pushing a box at constant velocity

What is friction?

A force that occurs when objects slide over each other

How is friction caused?

Atoms clinging together at many points of contact

What types of friction are there?

Static and Kinetic friction

What is kinetic friction?

When two objects are moving relative to each other

What is static friction?

When 2 objects are not moving relative to one another

What must you overcome when pushing a box at rest?

Static friction

What is proportional to the normal force?

Friction force

A smaller value of µ means what?

Less friction between the surfaces

What is Newton's 3rd Law of Motion?

Whenever one object exerts a force on a second object, the second object exerts an equal and opposite force on the first

What are the two objects called?

One is called the action force and the other is the reaction force, it doesn't matter which is which

The forces are _____ __ _________ ___ ________ __ _________.

Equal in magnitude and opposite in direction

The two forces occur when?

They occur simultaneously

what is the 3rd law often stated as?

For every action, there is an equal and opposite reaction

Why is what the 3rd law is often stated as wrong?

Because it is misleading since its implying the action happens before the reaction

What leads to the conclusion of action forces and reaction forces acting in pairs?

Action forces can't exist without reaction forces and vice versa

Do action and reaction forces act on the same object?

No because then they would cancel out since the are equal forces in opposite directions

A rifle fires a bullet and they both have equal forces but the bullet travels farther while the rifle only moves a little. Why does the bullet travel more?

Because the bullet has less mass than the rifle which will make it move farther