Chapter 3- Forces

Question 1

What is Newton’s 2nd Law?

Answer 1

The more mass an object the more force it will take to make it accelerate.

Question 2

What is the formula for newton’s 2nd law.

Answer 2

F=ma

Question 3

What is friction?

Answer 3

A force that can stop an object in motion

Question 4

What does friction want to do?

Answer 4

wants stop sliding motion

Question 5

What are microwelds?

Answer 5

the source friction

Question 6

How do microwelds form?

Answer 6

When bumps come in contact

Question 7

When are microwelds the strongest?

Answer 7

when a larger force pushes them together

Question 8

How do you break microwelds?

Answer 8

force must be applied

Question 9

What is static friction?

Answer 9

the force that prevents two forces from sliding past each other

Question 10

What else do I need to know about static friction?

Answer 10

static friction is where a force is canceling your push

Question 11

What is a force that isn’t strong enough to break microwelds?

Answer 11

Static Friction

Question 12

What is sliding friction?

Answer 12

a force that opposes motion of two surfaces sliding past one another.

Question 13

What is sliding friction caused by?

Answer 13

microwelds continually braking then forming again

Question 14

What do you have to do to keep something moving during sliding friction?

Answer 14

you have to constantly be pushing it

Question 15

What is rolling friction?

Answer 15

A force between a rolling object and the surface it rolls on

Question 16

What happens if static friction acts over a deformed area?

Answer 16

it causes rolling friction

Question 17

What is air resistance?

Answer 17

opposes the motion of objects through the air

Question 18

What direction does air resistance act in?

Answer 18

the opposite direction to a motion of an object through the air

Question 19

What would happen if air resistance didn’t exist?

Answer 19

All object would fall at the same speed.

Question 20

What does air resistance on an object depend on?

Answer 20

speed, size, and shape

Question 21

What is one thing Air resistance doesn’t depend on?

Answer 21

Mass

Question 22

What is terminal velocity?

Answer 22

the downward force of gravity causing and object to accelerate

Question 23

What happens when an object is falling very fast?

Answer 23

the upward force of the air resistance increase

Question 24

the net force of an object is when what happens?

Answer 24

there’s a balanced downward force of gravity

Question 25

What does terminal velocity depend on ?

Answer 25

size,shape and mass

Question 26

what is gravity?

Answer 26

an attractive force between any two objects

Question 27

What are the two things gravity depends on?

Answer 27

mass of the objects and distance between them.

Question 28

how does the force of gravity increase?

Answer 28

mass of either object increases, or the objects move closer together.

Question 29

Is gravity one of the four basic forces?

Answer 29

Yes

Question 30

What are 3 of the other basic forces?

Answer 30

electromagnetic force, strong nuclear force, and weak nuclear force.

Question 31

where do the 2 nuclear forces work?

Answer 31

on particles in the nuclei of atoms.

Question 32

What causes Electricity and magnetism?

Answer 32

electromagnetic force.

Question 33

What is the formula for gravitational force?

Answer 33

gravitational force= mass x acceleration(due to gravity)

Question 34

Can gravity ever be zero?

Answer 34

no matter how far apart 2 objects are gravity never goes to zero.

Question 35

what is it called when all forces except gravity can be ignored?

Answer 35

free fall

Question 36

How fast is the acceleration of an object in free fall near the earths surface?

Answer 36

9.8 m/s squared

Question 37

What is weight?

Answer 37

The gravitational force exerted on an object.

Question 38

Is weight a force?

Answer 38

yes

Question 39

What is mass?

Answer 39

a measure of the amount of matter an object contains.

Question 40

If you throw a ball horizontally what will it do?

Answer 40

It will go in a curve (gravity)

Question 41

if you drop a ball straight down and one as hard as possible horizontally will it fall at the same rate?

Answer 41

Yes

Question 42

When a ball goes around in a circle what change of direction is the velocity going in?

Answer 42

toward the center.

Question 43

What is acceleration toward the center of a curved path called?

Answer 43

centripetal acceleration

Question 44

When a ball has centripetal acceleration what is the direction of the net force?

Answer 44

The center of the curved path.

Question 45

What is the net force exerted toward the center of the curved path called?

Answer 45

Centripetal force.

Question 46

What is one thing that centripetal force works for?

Answer 46

when a car is turning it keeps it from falling over

Question 47

What is newton's 3rd laws?

Answer 47

for every action there is an equal or opposite reaction.

Question 48

what is an example of newton's 3rd law?

Answer 48

Trampoline

Question 49

What happens when a rocket exerts gasses on the ground.

Answer 49

newton's 3rd law and the rocket will go up as it pushes down on the ground.

Question 50

What is momentum?

Answer 50

the product of mass and velocity.

Question 51

What is the opposite of momentum?

Answer 51

Inertia

Question 52

Is momentum a force?

Answer 52

no

Question 53

What is the symbol for momentum?

Answer 53

P

Question 54

How can momentum change?

Answer 54

mass, velocity, or both change.

Question 55

Can momentum be transferred into different objects?

Answer 55

Yes

Question 56

If a ball is still what is its momentum?

Answer 56

there is none, it isn't lost or created.

Question 57

what is weightlessness?

Answer 57

When you have practically no gravity pulling you down (you feel weightless