Free Body Diagram Practice, Free body diagrams 2, Inertia - Multiple choice questions and true or false, 1 Dimensional Motion, Forces (Free Body Diagrams), Net Force, Net Force, Newton's third Law of Motion, Newton's Laws of Motion, Newton's third La...

acceleration due to gravity

A downward acceleration of 9.81 m/s2

Force

A push or a pull resulting from the interaction of an object

Force

A push or pull measured in Newtons

Unbalanced Forces

ALWAYS cause a change in motion. They are NOT equal in size, but ARE opposite in direction.

Third Law of Motion Pairs

Action-Reaction

Arrows Point in the Same Direction

Add the numbers.

Contact Forces (two objects MUST touch)

Air Resistance, Tension, Spring Force, Normal Force, Friction, Applied Force

Net Force

All forces acting on an object.

Newton's First 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.

Balanced Forces

DO NOT cause a change in motion. They are EQUAL in size and ARE opposite in direction.

Displacement

Distance and direction of an object's change in position from the starting point.

Force of gravity (Fgrav)

Downward force

Balanced Forces

Equal forces acting on an object in opposite directions.

Newton's Second Law of Motion

F=ma

True or False: An astronaut weighs the same on Earth as in space.

False

True or False: If a hockey puck were to slide on a perfectly friction less surface, it will eventually slow down because of its inertia

False

True or False: If you were to slide a hockey puck across a friction less ice rink, there must be a horizontal force on it to keep it in motion.

False

True or False: The SI unit of force is the kilogram

False

True or False: The SI unit of mass is the newton

False

True or False: The amount of matter in an object is it's weight

False

True or False: The force due to gravity acting on an object is it's mass

False

Law of Inertia

First Law of Motion

Newton's 3rd Law of Motion

For every action, there is an equal and opposite reaction.

Tension Force (Ften)

Force caused by pulling on a rope, chain, string, cable or something similar.

all objects will have this force exerted upon it

Force of gravity

Air Resistance Force (Fair)

Force that acts on an object as it travels through the air

Frictional Force (Ffrict)

Force that opposes motion

Action from a Distance Forces (two objects do NOT have to touch)

Gravity, Magnetic and Electrical Force

distance

How far an object moves

When an Object is NOT Moving

It is a balanced force.

Applied Force (Fapp)

Push or pull exerted by a person or another object

Inertia

Resistance of an object to change its motion

Arrows Point in the Opposite Direction

Subtract the numbers.

Mass

The amount of matter in an object

Acceleration

The change in velocity over time

Suppose you are on an airplane moving at high speed. If you flip a coin straight up it will land in your lap rather than a great distance behind you. Explain

The coin will land in your lap because everything is going at the same speed.

Speed

The distance an object travels per unit of time

Newton

The unit used to measure the amount of force

Law of Action-Reaction

Third Law of Motion

True or False: A force can simply be defined as a push or a pull.

True

True or False: An astronaut has the same mass on Earth as in space

True

True or False: Friction refers to the force between two surfaces that are sliding past each other

True

True or False: In the fourth century B.C. , Aristotle divided motion into two types: natural motion and violent motion

True

True or False: Inertia is the property that every material object has; inertia resists changes in an object's state of motion.

True

True or False: The reason a penny thrown straight up inside an airplane will come back to your hand is that you, inside the airplane, and the penny are all moving at the same horizontal velocity

True

The mass of a lam that weighs about 110N is about a. 1 kg b. 11 kg c. 110 kg d. 1100 kg e. none of the above

b. 11 kg M=w/g = M= 110/10= 11 M= 11-kg

The law of inertia applies to a. Objects at rest b. Both moving and non-moving objects c. moving objects

b. Both moving and non-moving objects

Compared to its weight on Earth, a 10-kg object on the moon will weigh a. The same amount b. Less c. More

b. Less

free body diagrams

simplified diagrams that show the magnitude and direction of forces; longer vector means greater force

net force

sum of all forces acting on an object

Velocity

the change in displacement over a period of time

Action at a Distance Forces

the concept that an object can be moved, changed, or otherwise affected without being physically touched by another object.

Acceleration

the rate at which velocity changes over time; an object accelerates if its speed, direction

normal force

the upward force caused by the surface an object lies upon.. it works in the opposite direction of gravity

23N -> OBJECT -> 23N

46 Newtons to the Right.

3N -> OBJECT <- 8N

5 Newtons to the Left.

8N -> OBJECT <- 3N

5 Newtons to the Right.

23N -> OBJECT <- 23N

0 Newtons (balanced force)

14N <- OBJECT -> 12N

2 Newtons to the Left.

12N <- OBJECT -> 14N

2 Newtons to the Right.

On the surface of Jupiter, the acceleration due to gravity is about 3 times that of earth. What would the mass of a 170-kg rock on Jupiter?

170-kg (It's a trick question, because mass is measured in kg's and the problem gives you the answer in kg's already.)

Unbalanced Forces

Unequal forces that cause an object to accelerate (speed up, slow down or change directions).

Newtons (N)

Unit of force

Normal Force (Fnorm)

Upward force that supports an object.

applied force

a literal push or pull such as a child pulling a wagon or a worker pushing a crate in a warehouse

tension

a pulling force caused by objects connected by a rope or cable

If the force of gravity suddenly stopped acting on the planets, they would a. Move in straight lines tangent to their orbits b. Spiral slowly towards the sun c. Continue to orbit the sun d. Spiral slowly away from the sun e. Fly straight away from the sun

a. Move in straight lines tangent to their orbits

Friction is a force that always acts a. Opposite to an object's motion b. Perpendicular to an objects motion c. In the same direction as an objects motion

a. Opposite to an object's motion (correct)

Compared to its mass on Earth, the mass of a 10-kg object on the moon is a. The same b. More c. Less

a. The same

Galileo found that a ball rolling down one inclined plane would roll how far up another inclined plane? a. To nearly it's original height b. The ball would not roll up the other plane at all c. To about one quarter it's original height d. To nearly twice it's original height e. To nearly half it's original height

a. To nearly it's original height (correct)

objects at rest remain at rest because...

all forces are balanced

air resistance

also called air friction or drag: upward force that resists the downward force of gravity

friction

always acts in the opposite direction of movement, caused by two surfaces rubbing against one another

contact forces

applied, friction, air resistance, tension, normal

You and a friend are jumping on a trampoline. Why does Earth, which is rapidly orbiting around the sun, not move under your feet when you jump? a. There are different rules in space and on the surface of the earth b. Newton's first law holds that your body moves along with Earth because it is not compelled to change it's motion by an unbalanced force c. Newton's second law holds that the acceleration produced by the force of gravity is offset by the friction of force on your feet d. Newton's third law holds that there is an equal and opposite force exerted by the trampoline on your feet, which allows you to move with Earth through space

b. Newton's first law holds that your body moves along with Earth because it is not compelled to change it's motion by an unbalanced force

An object weighs 30 N on Earth. A second object weighs 30 N on the moon. Which has the greater mass? a. The one on earth b. The one on the moon c. They have the same mass d. Not enough information to say

b. The one on the moon

An object following a straight-line path at constant speed a. Has no forces acting on it b. Has a net force acting on it in the direction of motion c. Has zero acceleration d. Must be moving in a vacuum e. None of the above

c. Has zero acceleration

One object has twice as much mass as another object. The first object also has twice as much a. Velocity b. Gravitational acceleration c. Inertia d. All of the above

c. Inertia

Which has more mass, a kilogram of feathers or a kilogram of iron? a. The feathers b. The iron c. Neither- they both have the same mass

c. Neither- they both have the same mass

A sheet of paper can be withdrawn from under a container of milk without toppling if the paper is jerked quickly. The reason this can be done is that a. Gravity pulls very hard on the milk carton b. The milk carton has very little weight c. The milk carton has inertia d. None of the above

c. The milk carton has inertia

The force required to maintain an object at a constant speed in free space is equal to a. The mass of the object b. The weight of the object c. Zero d. The force required to stop it e. None of the above

c. Zero

After a cannonball is fired into friction less space, the amount of force needed to keep it going equals a. Twice the force with which it was fired b. One half the force with which it was fired c. Zero, since no force is needed to keep it going d. The same amount of force with which it was fired e. One quarter the force with which it was fired

c. Zero, since no force is needed to keep it going

How much does a 3.0 kg bag of bolts weigh? a. 7.2 N b. 14.4 N c. 22.8 N d. 29.4 N e. 58.8 N

d. 29.4 N w= (m) (g) w= 3.0 x 10 = 30N

Friction a. Comes from microscopic bumps that act as obstructions to the objects motion b. Is the name given to the force acting between surfaces sliding past one another c. Acts in a direction that opposes the motion of an object d. All of the above e. None of the above

d. All of the above

The law of inertia states that an object a. Will continue moving at the same velocity unless an outside force acts on it b. Will continue moving in a straight line unless an outside force acts on it c. That is not moving will not will never move unless an outside force acts on it d. At rest will remain will at rest unless acted on by an outside force e. Will do all of the above

e. Will do all of the above

The 10-ball collides with the 14-ball on the billiards table (assume equal mass balls). The force experienced by the 10-ball is ____________ (less than, equal to, greater than) the force experienced by the 14-ball. The resulting acceleration of the 10-ball is ____________ (less than, equal to, greater than) the resulting acceleration of the 14-ball.

equal to, equal to

A bug crashes into a high speed bus. The force experienced by the bug is ____________ (less than, equal to, greater than) the force experienced by the bus. The resulting acceleration of the bug is ____________ (less than, equal to, greater than) the resulting acceleration of the bus.

equal to, greater than

A bullet is loaded in a rifle and the trigger is pulled. The force experienced by the bullet is ____________ (less than, equal to, greater than) the force experienced by the rifle. The resulting acceleration of the bullet is ____________ (less than, equal to, greater than) the resulting acceleration of the rifle.

equal to, greater than

A massive linebacker collides with a smaller halfback at midfield. The force experienced by the linebacker is ____________ (less than, equal to, greater than) the force experienced by the halfback. The resulting acceleration of the linebacker is ____________ (less than, equal to, greater than) the resulting acceleration of the halfback.

equal to, less than

Objects with smaller masses have

less inertia

A person weighs 650N. What is the mass of the person?

m= w/g =650/10 =65-kg

SI unit for force or weight

newton (N)

Forces always exist in ..

pairs

How much (in newtons) does a 10.0-kg bag of grass seed weigh?

w= (m) (g) 10.0 x 10 =100N

On the surface of Jupiter, the acceleration due to gravity is about 3 times that on earth. How much would a 0.40-kg rock weigh on Jupiter?

w= (m) (g) = 0.40 x 30 =12N

How much (in newtons) does 0.60 kg of salami weigh?

w= (m) (g) =0.60 x 10 =6N