Forces

Question 1

What is a force?

Answer 1

A force is a PUSH or a PULL on something.

Question 2

what are the 4 fundamental forces?

Answer 2

gravitational, electromagnetic, weak nuclear and strong nuclear

Question 3

gravitational force

Answer 3

Force of attraction between all objects

e.g. planets in orbit

Question 4

electromagnetic force

Answer 4

Force cased by electric charges

e.g. chemical reactions; electricity

Question 5

weak nuclear force

Answer 5

Forces in-between elementary particles

e.g. involved in particle transformations

Question 6

strong nuclear force

Answer 6

Attraction between neutrons and protons

e.g. nuclear reactions

Question 7

A force is a ____ or ____ upon an object
resulting from the object’s _________ with
another object.

Answer 7

push; pull; interaction

Question 8

Whenever there is an ________ (two objects
affecting each other in some way) between
two objects, there is a _____ upon each of the
objects.

Answer 8

interaction; force

Question 9

When the _____ ceases, the two
objects no longer experience the force. Forces
_____ exist as a result of an interaction.

Answer 9

interaction; only

Question 10

all forces (interactions) between objects can be placed into two broad categories:

Answer 10

contact forces and forces resulting from action at a distance

Question 11

____________ are types of forces in which the
two interacting objects are _____________ each other.

For example: Friction, air resistance, applied forces (when a push a book across the desk).

Answer 11

Contact forces; physically
contacting

Question 12

_______________ are types of forces
in which the two interacting objects are not in
physical contact with each other, yet are able
to exert a __________ despite a physical
separation.

Answer 12

Action-at-a-distance forces; push or pull

Question 13

Examples of action-at-a-distance forces

Answer 13

gravitational forces (e.g., the sun and planets exert a gravitational pull on each other despite their large spatial separation)

electric forces

magnetic forces

Question 14

Force is a quantity which is measured using
the standard metric unit known as the ________.
One Newton is the amount of force required to
give a 1-kg mass an acceleration of 1 m/s2. A
Newton is abbreviated by a “N.”

Answer 14

Newton

Question 15

A force is a ________

Answer 15

vector quantity

Recall, that a vector quantity is a quantity which has both magnitude and direction.

Question 16

To fully describe the force acting upon an object, you must describe…

Answer 16

both the magnitude (size) and the direction.

Question 17

it is common to represent forces using diagrams
in which a force is represented by ________

Answer 17

an arrow

Question 18

system diagrams

Answer 18

System Diagrams (sketch showing all the objects
involved)

Question 19

free body diagram or FBD

Answer 19

shows only the forces.

Question 20

Free-body diagrams are diagrams used to show the ___________________ of all forces acting upon an object in a given situation.

Answer 20

relative magnitude and direction

Question 21

The size of the arrow in a free-body diagram is
reflective of the ________ of the force.

Answer 21

magnitude

Question 22

The direction of the arrow reveals the ________

Answer 22

direction which the force is acting.

Question 23

dynamics

Answer 23

the study of the causes of motion

Question 24

applied force

Answer 24

a force that results when one object makes contact with another and pushes or pulls on it

Question 25

tension

Answer 25

a pulling force from a rope
or string on an object that always points
toward the rope or string

Question 26

normal force

Answer 26

a perpendicular force
exerted by a surface on an object in
contact with the surface; the normal force
always points away from the surface

Question 27

friction

Answer 27

opposes the sliding of two
surfaces across one another; friction
acts opposite to the motion or attempted
motion

Question 28

force of gravity

Answer 28

force of attraction
between any two objects

Question 29

net force, (also known as total force or
resultant force)

Answer 29

the sum of all the forces acting on an object.

Question 30

inertia

Answer 30

the property of an object that resists change in its state of rest or motion

Question 31

Newton’s first law of motion

Answer 31

if the net force acting on an object is zero, the object will remain at rest or move at a constant velocity

Question 32

implications

there must be an _____________ in order to change motion

Answer 32

external force

Question 33

moving objects will continue to move in a ___________ at a __________ unless acted on by an __________________________

Answer 33

straight line; constant speed; external net force greater than zero

Question 34

factors

inertia is directly proportional to the ______ of the object

Answer 34

mass

Question 35

factors

therefore, _____ objects are harder to _____ moving and will also be harder to ____ moving

Answer 35

heavier; start; stop

Question 36

true or false:

the gravitational field intensity and force of gravity are the same thing

Answer 36

false

Question 37

true or false

the force of friction operates in the same direction as the motion

Answer 37

false

Question 38

inertia is a property of objects that resist changes to the object’s state of motion or rest

Answer 38

true

Question 39

true or false

gravitational force exists only on Earth

Answer 39

false

Question 40

true or false

the normal force always acts in the exact opposite direction as the force of gravity

Answer 40

false (not always)

Question 41

true or false

The net force on an object is the sum of all the forces acting on it.

Answer 41

true

Question 42

true or false

If the net force on an object is constant and the mass decreases, then the acceleration increases.

Answer 42

true

Question 43

true or false

Newton’s third law states that for every action force, there is a simultaneous reaction force of equal magnitude acting in the same direction.

Answer 43

false