Vocabulary

When the upward and downward forces on a falling object are equal, the object reaches
_____________.

Terminal Velocity

Vocabulary

The force that holds the particle sin the nucleus together is the
__________.

Strong Nuclear Force

Vocabulary

The SI unit for force is _______.

Newton (N)

Vocabulary

A push or pull that starts or stops the motion of an object or changes its direction is called a(n) __________.

Force

Vocabulary

Gravitation, electromagnetic, and strong and weak nuclear forces are _________.

Universal Forces

Vocabulary

When you body is at rest, you have __________.

Inertia

Vocabulary

The force that opposes motion is
__________.

Friction

What Doesn’t Belong?

Universal Force, Electromagnetic
Force, Gravitational Force.

Universal Force- this is the general term that includes electromagnetic and gravitational forces.

What Doesn’t Belong?

Sliding, Rolling, Momentum

Momentum- Sliding and rolling are types of friction; momentum is a property of a moving object.

What Doesn’t Belong?

Electrical, Magnetic, Centripetal

Centripetal Force- Electric and magnetic are forces between objects; centripetal force is the force required to make an object move in a circle.

What Doesn’t Belong?

Terminal Velocity, Constant
Acceleration, Friction

Constant Acceleration- Terminal velocity is reached because of friction between the object and the air.

What Doesn’t Belong?

Weak Force, Strong Force,
Sliding Force

Sliding Force- the sliding force is not one of the universal forces.

Check Your Knowledge

What causes a ball to follow a curved path when you throw it?

A thrown ball follows a curved path because of the force of gravity on the ball.

Check Your Knowledge

What is terminal velocity?

Velocity at which the force of gravity pulling down on a falling object is exactly balanced by the force of air resistance pushing upward, resulting in that object falling at a constant velocity.

Check Your Knowledge

How is gravity related to the weight of an object?

The weight of an object is a result of the force of gravity on the object.

Check Your Knowledge

List three different kinds of force you use when you ride your bike.

Force of your muscles on the pedals and handlebars; force of your weight on the seat; force of friction from the pavement pushing on the tires; force of gravity on the bike.

Check Your Knowledge

Calculate the acceleration of a
70-kg mass on a swing if you push it with a 40-N force.
 a=F/m; a= 40N/70kg; a=
0.57m/s 2 .

Check Your Knowledge

How does the force of gravity form the moon affect the Earth?

The force of gravity from the moon causes tides on Earth.

Check Your Knowledge

What is centripetal force?

Centripetal force- a force that causes an object to move in a circular path.

True or False?

The force that holds the nucleus together is the strong nuclear force?

True

True or False?

Momentum can transfer from one object to another object.

True

True or False?

The acceleration of the Earth’s gravity is 9.8m/s 2 .

True

True or False?

According to Newton’s second law, acceleration decreases as mass increases.

True

True or False?

According to the second law of motion, force is equal to mass times speed.

False; acceleration

True of False?

The electric force and the magnetic force are both a result of charge particles.

True

True or False?

Newton’s third law of motion could be called the law of inertia.

False; first

Check Your Understanding

An object’s velocity times its mass is _______.

Momentum

Check Your Understanding

What are the three types of friction and when do they occur?

Fluid friction- when moving through air or liquid. Rolling friction- friction that occurs between a rolling object and another surface. Sliding frictionfriction that occurs between two objects that are sliding past one another.

Check Your Understanding

Rank the strength of the universal forces from weakest to strongest.

1. Gravitational 2. Weak Nuclear
3. Electromagnetic 4. Strong
Nuclear

Check Your Understanding

Which kinds of forces attract?
Which kind repel?

Like forces repel and opposite forces attract.

Check Your Understanding

What do nuclear forces act on?
What makes one weak and the other strong?

Nuclear forces act on the nucleus of atoms (protons and neutrons).
Strong nuclear forces keep the nucleus together; Weak Nuclear forces cause nuclear decay.

Check Your Understanding

Which object will accelerate faster when the same amount of force is applied to them, a cart that weighs 20kg or a cart that weighs 40 kg?

The 20kg cart.

Check Your Understanding

Is the force needed to overcome sliding friction greater than or less than the force needed to overcome rolling friction?

Greater than

Check Your Understanding

If you were to travel to a planet that has less gravity than earth, would you weigh: the same as, less than, or greater than you do on earth?

Less than