CH 4-5-6 Flashcards Preview

2019 PHYSICS fall > CH 4-5-6 > Flashcards

Flashcards in CH 4-5-6 Deck (84)
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1

What weighs 1 N?

an apple

2

What weighs 10N?

Large Textbook (a 1 liter bottle of soda)

3

What weighs 100N?

3 Gallons of milk

4

What weighs 1000N?

Mr. Nystrom wearing a backpack full of books

5

If you weigh 600N and are hanging on a rope, you are pulling down 600N on the rope. The rope is pulling ______

up 600N on you!

6

If you weigh 600N and jump off of a building, do you accelerate towards the earth? Does the earth accelerate towards you?

YES, you accelerate toward the earth and YES the earth accelerates toward you (it is hard to see)

7

How can you think of gravity to help you "see" objects being pulled towards eachother?

Imagine a bungee between them. A bungee between two cars may pull them both together at the same acceleration, but a bungee between a car and a skateboard will mostly pull the skateboard more. MASS RESISTS ACCELERATION

8

Why don't you see the earth move when you jump up?

It is so massive that it barely moves

9

If force = mass * acceleration, then acceleration =

FORCE / MASS

10

if force = mass * acceleration, then mass=

FORCE / ACCELERATION

11

When you fire a gun, the force on the bullet is equal to the _____________

force on the gun

12

why does a bullet go faster forward than the gun moves backwards if they have the same force?

the gun has more mass. If you push a roller skate with the same force that you push a bus, the rollerskate will accelerate faster! Mass resists acceleration.

13

What is a way to think of mass when it comes to movement?

MASS RESISTS ACCELERATION (this is what we call inertia)

14

How do you sketch the resultant force of two vectors?

USE THE PARALELLOGRAM RULE.

15

What does the delta (the little triangle) symbol mean?

It means "CHANGE IN"

16

What is Newton's First Law?

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

17

What is Newton's Second Law?

F= ma Force increases acceleration, mass resists accelertion

18

What is Newton's Third Law?

Every action (force) has an equal and opposite reaction

19

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

FIRST: objects in motion or rest stay that way, SECOND: harder to push more massive objects , THIRD: action have equal opposite reactions

20

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

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

21

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

mass, m= F/a

22

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

Force, F= ma

23

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

a = F/m

24

Describe what NET force is

It is what is left after you combine all the forces (things cancel out).

25

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

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

26

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

press MODE> put cursor on DEGREES> press ENTER

27

What is the net force on an object at rest?

zero (not accelerating), but has potential energy!

28

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

zero (not accelerating) but has kinetic energy!

29

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

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

30

block on inclined plane: What is Fd and FN?

Fd is directional force DIAGONAL down plane along the slope, FN is normal force directly into the plane