Forces

Question 1

What is a force?

Answer 1

A push or a pull

Question 2

What does a force cause?

Answer 2

It causes something to start moving, stop moving, or change direction or speed

Question 3

How are forces described?

Answer 3

by their strength (magnitude) and by their direction, which are represented by arrows

Question 4

What is the strength of force measured in?

Answer 4

SI Units: Newtons (N)

> named after Isaac Newton who is a British scientist, created law of motion, and the apple fell on his head

Question 5

When more than one force is exerted at the same time, you can calculate the ___.

Answer 5

net force

Question 6

What does the net force tells you

Answer 6

if an object will move and in what direction

Question 7

Forces acting in the same direction get ____ (add/subtract/multiplied/divided) together to determine the NET FORCE.

Answer 7

added

Question 8

If the forces are moving in the opposite direction, then you ____ to get the net force.

Answer 8

subtract

Question 9

Forces will cancel each other out when they are ____ in magnitude and ___ in direction. Net force will equal ___.

Answer 9

equal, opposite, 0

Question 10

When there IS a net force, the forces are considered to be ______.

Answer 10

unbalanced

Question 11

Unbalanced forces will cause an object to _______, _____, _______.

Answer 11

start moving, stop moving, or change direction

Question 12

When more than one force is being exerted from ___ directions but are ___ in magnitude, the result is _____.

Answer 12

opposite, equal, no change in motion

Question 13

What is friction?

Answer 13

When 2 surfaces rub against each other, the force that they exert on each other is called friction

Question 14

How does friction work?

Answer 14

Friction works opposite to motion and causes the object to slow down.

Question 15

What does the strength of friction depend on?

Answer 15

It depends on

1. how hard the surfaces are pushed together
2. how rough the surfaces are

Question 16

What are the four type of frictional forces?

Answer 16

1. Static Friction
2. Sliding Friction
3. Fluid Friction
4. Rolling Friction

Question 17

What is static Friction?

Answer 17

It is the friction that acts on objects that are not moving.

*In order to make something move, you have to overcome static friction.

Question 18

What is sliding friction?

Answer 18

It is the friction that occurs when two solid surfaces slide over each other.
*The rougher two surfaces are, the more friction there is Ex: shoes and the floor, hands rubbing together

Question 19

What is rolling friction?

Answer 19

It is the friction that occurs when an object rolls a surface.
> It’s easier to overcome rolling friction because there is less surface area that comes in contact with the surface, such as a bowling ball against the floor.

Question 20

What is fluid friction?

Answer 20

It is the friction that occurs when a solid object moves through a fluid.
> Scientists consider liquids AND gases to be fluids
(Friction in a gas is also called air resistance)
Ex: Human in a pool, bird through air

Question 21

What is gravity?

Answer 21

It’s the force of attraction between any two objects

> It’s a pulling force

Question 22

Why can we feel the force of gravity towards Earth?

Answer 22

We can feel it because the Earth is so massive.

Question 23

What two things does gravity depend on?

Answer 23

it depends on:

1. the MASS of the objects
2. the DISTANCE between them

Question 24

What is the rate of acceleration due to gravity on Earth?

Answer 24

It 9.8 m/s/s

*It is often rounded to 10 m/s/s

Question 25

The amount of gravity a planet has depends on that ______.

Answer 25

planet’s mass

Question 26

Mass is sometimes confused with weight, butt mass is the ____ in an object or person.

Answer 26

amount of matter

Question 27

Weight is a measure of the _____.

Answer 27

amount of gravity exerted on an object or person

Question 28

The more gravity that a planet exerts, the more you would _____.

Answer 28

weigh