# Chap 4 and 5 Newton's Laws Flashcards Preview

## 2018 PHYSICS 10 CONCEPTUAL > Chap 4 and 5 Newton's Laws > Flashcards

Flashcards in Chap 4 and 5 Newton's Laws Deck (48)
1
Q

What is Newton’s First Law?

A

Object stays at rest, or moves at a constant velocity in a straight line unless a force acts on it.

2
Q

What is Newton’s Second Law?

A

a= F/m Force increases acceleration, mass resists accelertion

3
Q

What is Newton’s Third Law?

A

Every action (force) has an equal and opposite reaction

4
Q

Give a quick summary of Newton’s three laws of motion:

A

FIRST: objects in motion or rest stay that way, SECOND: a = F/m , THIRD: action have equal opposite reactions

5
Q

What are the three equations from newton’s second law? (my fish is from massachusetts)

A

a=F/m
F= ma
F/a = m

6
Q

If you are given a force and an acceleration, you can find ____ by using the equation ____

A

mass,

m= F/a

7
Q

If you are given a mass and an acceleration, you can find ____ by using the equation ____

A

Force,

F= ma

8
Q

If you are given a force and a mass, you can find ____ by using the equation ____

A

a = F/m

9
Q

Describe what NET force is

A

the resultant force after you consider the combination of all the forces acting on an object

10
Q

How can we add two vectors (find resultant) by sketching?

A

Use the parallelogram rule, and the DIAGONAL is the resultant vector when both components start from the same spot.

11
Q

How do we find the components if we have the resultant?

A

Generally, the resultant is the hypotenuse of a right triangle. So the closest side (adjacent) to the angle can be found by HYPcos(angle) and the opposite side (across) from the known angle can be found by HYPsin(angle)

12
Q

How do we make sure our calculator is in the right mode?

A

press MODE> put cursor on DEGREES> press ENTER

13
Q

What is the net force on an object at rest?

A

zero (not accelerating), but has potential energy!

14
Q

What is the net force on an object moving at a constant velocity? Why?

A

zero because it is not accelerating ( but has kinetic energy!)

15
Q

What has to be happening in order for net force to not be zero?

A

it must be ACCELERATING (changing velocity). just moving is not enough, it has to be changing speeds!

16
Q

SOH CAH TOA… What do these stand for?

A

Sin angle= opp/hyp

17
Q

block on inclined plane: What is Fd and FN?

A

Fd is direction of motion, force down plane along the slope, FN is normal force directly into the plane

18
Q

Directional force is:

A

Fd is directional, or down the plane, parallel to the plane, along the plane

19
Q

If you have weight, how do you find normal force?

A

w*cos (angle) gives normal force.

20
Q

If you have weight, how do you find directional force?

A

w*sin(angle) gives the directional force

21
Q

Normal force is:

A

FN is normal force, it is perpendicular to the plane (straight down into the plane). This determines amount of friction.\

22
Q

The force of friction always acts____

A

in the opposide direction of motion

23
Q

You can calculate the force of friction by multplying ____ by ____

A

normal force by coefficient of friction

24
Q

Coefficients of friction are _____ for surfaces that are smooth and ____ for surfaces that are rough, or sticky.

A

smaller, larger

25
Q

What is the unit of force we use?

A

NEWTON

26
Q

What is the unit of weight we use?

A

NEWTON

27
Q

What are the units in a NEWTON?

A

kg*m/s2

28
Q

what are the units we use for acceleration?

A

m/s2

29
Q

What are the units we use for mass?

A

kg

30
Q

a newton divided by acceleration (m/s2) will give you

A

mass (kg)

31
Q

a newton divided by a mass (kg) will give you

A

an acceleration (m/s2)

32
Q

a mass (kg) multiplied by an acceleration (m/s2) will give you

A

a newton (force)

33
Q

How much does a 3kg object weigh?

A

34
Q

Is acceleration scalar or vector?

A

vector (has direction and magnitude)

35
Q

What is acceleration when 12N is applied to 3kg object? Why?

A

4 m/s2
because a=F/m
a= 12/3

36
Q

What is the net force on a 10kg object that is accelerating at 2 m/s2

A

F = ma
so
F= 10(2) = 20N

37
Q

What is the mass of an object that acceleraties 5 m/s2 when a 30N force is applied?

A

m= F/a

so m= 30/ 5 = 6kg

38
Q

What force do you need to accelerate a 1000kg car 5 m/s2 ? (ignore friction)

A

F=ma so f=1000(5) = 5000N

39
Q

What will the acceleration be of an 800kg car that is pushed with a force of 8000N? (ignore friction)

A

a=F/m so a= 8000/800 = 10m/s2

40
Q

What is terminal velocity?

A

the greatest speed a falling object will reach because of air resistance

41
Q

What is the net force on an object that is moving at its terminal velocity? Explain

A

zero. it is not accelerating

42
Q

What receives a greater force of air resistance, an elephant or a feather falling? Why?

A

elephant. it is pushing through more air

43
Q

What is the difference between mass and weight?

A

mass is the amount of stuff, weight is the force down caused by the gravitation of the planet it is on

44
Q

Which is more stable, mass or weight? Explain

A

mass is same on earth or moon, weight changes

45
Q

Give an example of Newton’s first law in real life:

A

an apple on a desk. net force is zero, until you push it off

46
Q

Give an example of Newton’s second law in real life:

A

harder to push a car than to push an apple

47
Q

Give an example of Newton’s third law in real life:

A

the floor is pushing up on you as much as you are pushing down on the floor

48
Q

When a bullet leaves a gun, explain why the bullet moves faster forward than the gun moves backward

A

bullet has small mass, lots of acceleration,

gun has lots of mass, little acceleration