Science Unit Test

Vocab, science questions

Newton’s 3rd Law

When one object applies a force to a second object, the second object applies an equal but opposite force to the first object. What law is this?

Newton’s 1st Law

Unless acted upon by an unbalanced force, an object at rest will remain at rest and an object in motion stays in motion going the same speed and same direction. What law is this?

Weight

The measure of the gravitational pull on an object that is measured in Newtons.

Drag

The specific term used for the force on a plane that is caused by air resistance.

Air resistance

The term used for friction with the air.

Terminal Velocity

The constant speed that a falling object eventually reaches when the upward force of air resistance balances the downward pull of gravity.

Net Force

The combination of all the forces acting on an object.

Mass

The amount of matter that makes up an object and is measured in grams

Newton’s 2nd Law

The acceleration of an object depends on the mass of the object and the amount of force applied. It is often expressed with the equation a=F/m or F=ma. What law is this?

Newton

Metric unit for measuring force. It is equal to one kg of mass accelerating at 1 m/s/s

Force

Any push or pull acting on an object.

Reference Point

An object that is usually stationary that is used to help describe the motion of other objects.

Gravity

An attractive force that all objects have on other objects depending on their mass and distance between the two objects

Vacuum

An area that has all the air removed

Acceleration

A vector quantity that measures the rate of change in velocity of an object. An object does this whenever it speeds up, slows down, or simply changes direction.

Velocity

A vector quantity that measures not only the speed of an object but also its direction.

Speed

A term used to describe how long it takes for an object to cover a certain distance. It is measured by taking the distance traveled and dividing by the time it takes to go that distance.

Motion

A term used to describe an object’s change in position which depends on the reference point.

Inertia

The tendency of all objects with mass to resist a change in motion. Objects with more mass will have more of this.

Friction

A general term to describe the force that exists whenever two objects are in contact with each other. This force always opposes motion and causes all objects to slow down.

A force is any ____ or ____

push or pull

What are three noncontact forces?

gravity magnetism electricity

All forces have both _____ and _____.

size and direction

Metric unit for force is ______.

Newton

To determine the net force of two forces acting in the same direction you must ___ the two forces.

add

To determine the net force for two forces acting in opposite directions, you must ________ the smaller force from the larger one.

subtract

If the net force acting on an object is equal to zero, then the forces on the object must be ________.

balanced

If the net force acting on an object is greater than zero, then the forces acting on the object must be __________.

unbalanced

A pencil has no gravity. (True or false)

False

The strength of gravity between 2 objects will depend on the ____ of each object and the ________ between the centers of both objects.

mass and distance

As a falling object moves faster, the air resistance _________.

increases

When the upward force of air resistance balances the downward force of gravity for a falling object, the falling object will no longer __________ but it will continue to fall at a constant rate. This is called ________ velocity.

accelerate terminal

how do you calculate your weight into newtons?

divide by 2.2

The second law can be summed up with what equation?

F=ma

How would you describe earth’s gravitational force?

large and pulls objects towards itself

In which situation is it better to have low friction?

a hockey puck sliding toward the goal

The earth’s gravitational force causes all objects to accelerate downward at what rate?

9.8 m/s/s

In order for an object to achieve its terminal velocity, the force of gravity must be..

equal to air resistance

The moon’s gravitational pull is ______ the earth’s gravitational pull.

6 times weaker than

what is the best reason why friction is considered a contact force?

because friction occurs every time two surfaces touch eachother.

A force is

any push or pull and a vector quantity

What are two examples of a vector quantity?

velocity and force