CH6, 7, 8 and trig mixed

Question 1

Where is the hypotenuse?

Answer 1

It is the longest side. Always the side across from the right angle. It is the diagonal.

Question 2

If you drag a block 20m with 5N or force, how much work did you do?

Answer 2

100 newton meters, or 100 JOULES

Question 3

Where is the “adj” side?

Answer 3

if you imagine standing in a triangular room in the same corner as the angle. The adjacent side is the side you can touch that is not the hypotenuse. It makes the angle with the hypotenuse.

Question 4

mv = Ft what does this say?

Answer 4

It is FAT MAV without the deltas

Question 5

How much energy in a 4kg block traveling 3 m/s

Answer 5

KE = mv2/2 = 4*3^2 / 2 = 36/2 = 18 J

Question 6

What does the delta triangle mean?

Answer 6

It means “CHANGE IN”

Question 7

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

Answer 7

force on the gun

Question 8

How do yu find the side furthest from the angle (opposite the angle) if you have the hypotenuse?

Answer 8

hyp * sin angle

Question 9

How are FORCE and MOMENTUM different?

Answer 9

Force = mass (acceleration) where Momentum = mass (velocity). Momentum is present when an object is moving at a constant speed, Force needs acceleration to be present.

Question 10

there are ______ of FORCE, ____ of WORK ,______ of POWER and _____ of ENERGY

Answer 10

NEWTONS of force, JOULES of work, WATTS of power and JOULES of energy

Question 11

What do the interior angles of a triangle add up to?

Answer 11

180 degrees, since a right triangle already has a 90 degree angle, the other two angles are complementary (add to 90)

Question 12

When a cannon is fired, explain how momentum is preserved.

Answer 12

mv(cannon) + mv(ball) before is ZERO. It has to be zero after, so the momentum the cannon moves must be opposite the momentum of the ball to cancel it out, so they must have the same magnitide. so after the cannon fires, MV (cannon) = MV (cannonball).

Question 13

When you fire a gun, the momentum of the bullet just after the shot is equal to____

Answer 13

the momentum of the gun right after the shot.

Question 14

What are the units of ENERGY?

Answer 14

JOULES - think of it as “work waiting to be done” or “stored work”

Question 15

Which causes more impulse, a 1kg ball hitting you at 10m/s and falling, or a ball bouncing off your head and traveling back at 5 m/s?

Answer 15

A ball bouncing causes more of an impulse. Impulse is change in momentum. The ball that stops velocity only changes 10m/s (from 10 to 0), the bouncing ball goes from +10m/s to -5m/s, an overall change of 15m/s. The more the velocity changes, the more the momentum changes, which is a larger impulse!

Question 16

How much power if you move 50 kg 20 meters in 10 seconds?

Answer 16

P = Fd / t = 50*20/10 = 100 WATTS

Question 17

if force = mass * acceleration, then mass=

Answer 17

FORCE / ACCELERATION

Question 18

Explain WORK units three ways

Answer 18

JOULE, or Nm, or kg*m2/ s2

Question 19

What is the unit of work we use?

Answer 19

JOULE (newton*meter)

Question 20

What is work?

Answer 20

FORCE X DISTANCE (in the direction of the applied force). Measured in JOULES

Question 21

If two objects have the same velocity, the one with the larger mass has _____ momemtum

Answer 21

larger

Question 22

What is “FAT MAV?”

Answer 22

F delta T = m delta v (force * change in time = mass * change in velocity)

Question 23

You lift 8kg up 5 meters, How many JOULES?

Answer 23

400 Joules

Question 24

When you have sides of a triangle, but are trying to find out what an angle is, what do you have to use?

Answer 24

trig -1 (untrig, inverse trig, arctrig)

Question 25

What is kinetic energy?

Answer 25

one half mass velocity squared. MOVING energy.

Question 26

What types of collisions do we usually consider when solving problems in class?

Answer 26

We assume they are elastic collisions (similar to how we often ignore friction).

Question 27

sin f / cos f = tan ___

Answer 27

f

Question 28

sin 70 = cos __

Answer 28

20

Question 29

How to solve triangles when there are no angles given?

Answer 29

PYTHAGOREAN THEOREM

Question 30

*** BONUS*** | If a 1 kg ball moving at 20m/s makes a 2cm dent in a wall. What was the force?

Answer 30

using F = m (delta v / delta t). We have m= 1kg, delta v = 20m/s- 0= 20m/s all we need is time. To find time, you need to user d = VT , or T = D/V... in this case, average velocity is (20 + 0)/2 = 10m/s .. so T = .02m/ 10m/s = .002 sec.

Question 31

What are the three possible situations when solving trig ratios?

Answer 31

1. solving for angle: trig x = A/B just untrig: X= trig-1 (A/B) 2. solving for numerator: trig angle = X/B just slide the B: X= B trig angle 3. solving for denominator: trig angle = A/X just switch: X = A/(trig angle)

Question 32

F = ma can be changed to what?

Answer 32

change the a to (delta v / delta t) so you get: F = m (delta V / delta T) this is another version of fat mav.

Question 33

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

Answer 33

MASS RESISTS ACCELERATION (this is what we call inertia)

Question 34

If you have a force and need to find the X and Y component, how do you do it?

Answer 34

The force given is always the hypotenuse of a right triangle. So draw an X and a Y component (a triangle). The closest (adjacent) side use FORCE * COS (ANGLE) and for the far (opposite) side use FORCE * SIN (ANGLE).

Question 35

What are the two energies we talk about in this unit?

Answer 35

Potential (height) and Kinetic (speed)

Question 36

What is an inelastic collision?

Answer 36

When some momentum, some energy is lost through heat, sound, etc

Question 37

What are the three conservation of momentum equations we use in this class? (along with the situations

Answer 37

``` mv+mv= mv + mv (separate before and after). (m+m)v = mv + mv (stuck before). mv+mv= (m+m)v (stuck after) ```

Question 38

How to solve for x: trig angle = X/B

Answer 38

SLIDE: B trig angle = x

Question 39

If something is moving at a constant velocity, what do we know about force and momentum?

Answer 39

At constant velocity, a body is in equilibrium (all the forces cancel out). Because it is not accelerating, the net force is ZERO. But, because it is moving, there is momentum

Question 40

Conservation equation

Answer 40

PEo+KEo = PEf +KEf or mgh+1/2 mv2 = mgh + 1/2 mv2 (notice the mass can cancel if it doesn't change)

Question 41

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

Answer 41

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

Question 42

How to solve for x: trig X = A/B

Answer 42

UNTRIG: trig-1 (A/B) = x

Question 43

If you are given the hypotenuse and need to find the side closest to the angle, how do you find it?

Answer 43

hyp * cos angle

Question 44

What is potential energy?

Answer 44

mgh- non-moving stored energy. from HEIGHT.

Question 45

NEWTONS measure____

Answer 45

Force

Question 46

What changes the momentum of an object?

Answer 46

Applying a force over an amount of time (WHICH IS IMPULSE!!). Impulse changes momentum.

Question 47

If you do 20 joules of work using 5N of force, how far did you go?

Answer 47

WORK/FORCE=DISTANCE so 20 joules/ 5 newtons= 4 meters

Question 48

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

Answer 48

up 600N on you!

Question 49

WATTS measure ____

Answer 49

Power

Question 50

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

Answer 50

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.

Question 51

How is work different from energy?

Answer 51

WORK is being done, Energy is work waiting to be done, like a battery wating to be used.

Question 52

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

Answer 52

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

Question 53

When you get the resultant X and the resultant Y, how do you find the direction (angle) of the resultant force?

Answer 53

angle to horizontal = tan-1 (Fy/Fx)

Question 54

When do you have to use trig-1, aka UNTRIG,inverse trig, or arctrig?

Answer 54

when you are trying to FIND AN ANGLE (not a side)

Question 55

How do you combine forces mathematically?

Answer 55

break the forces down into X and Y components and then combine all the X components and all the Y components into a resultant X and resultant Y. Sketch it. The diagonal of the rectangle is the resultant force and it goes in that direction.

Question 56

What is impulse?

Answer 56

Change in momentum, or FORCE*TIME (a force over an amount of time changes momentum)

Question 57

JOULES measure _____

Answer 57

Work and Energy

Question 58

What weighs 1000N?

Answer 58

Mr. Nystrom wearing a backpack full of books

Question 59

What is momentum?

Answer 59

MASS * VELOCITY

Question 60

You lift 8kg up 5 meters in 4 seconds, how many WATTS of power?

Answer 60

100 watts

Question 61

You lift 8kg up 5 meters in 20 seconds, how many WATTS of power?

Answer 61

20 watts

Question 62

IF WORK=FORCExDISTANCE, then FORCE=

Answer 62

WORK/DISTANCE

Question 63

What are two ways to change momentum?

Answer 63

Change the mass or change the velocity

Question 64

If you do 10 joules of work over 5 meters, how much force?

Answer 64

WORK/DIST= FORCE so 10 Joules/ 5 meters = 2 NEWTONs

Question 65

If force = mass * acceleration, then acceleration =

Answer 65

FORCE / MASS

Question 66

As velocity increases, momemtum _____

Answer 66

increases

Question 67

How to solve for x: trig angle = A/X

Answer 67

SWITCH: A/trig angle = x

Question 68

Explain POWER units three ways

Answer 68

WATT or joule/s or kg*m2/s3

Question 69

What is the unit of energy we use?

Answer 69

JOULE (newton*meter)

Question 70

If you are given the hypotenuse and need to find the side opposite the angle, how do you find it?

Answer 70

hyp * sin angle

Question 71

How do you find the side closest to the angle (adjacent to the angle) if you have the hypotenuse?

Answer 71

hyp * cos angle

Question 72

When solving right triangles using trig, what do we do first?

Answer 72

LABEL THE H, the O and the A, then figure out which ratio to use, soh, cah or toa

Question 73

What weighs 10N?

Answer 73

Large Textbook (a 1 liter bottle of soda)

Question 74

What does "conservation of momentum" mean?

Answer 74

Momentum before = momentum after

Question 75

In a right triangle, the sine of one of the acute angles always equals the ____ of the other acute angle

Answer 75

Cosine

Question 76

what are units of momentum?

Answer 76

mass*velocity, so kg*m/s

Question 77

How do you sketch the resultant force of two vectors?

Answer 77

USE THE PARALELLOGRAM RULE.

Question 78

What weighs 100N?

Answer 78

3 Gallons of milk

Question 79

IF WORK=FORCExDISTANCE, then DISTANCE=

Answer 79

WORK/FORCE

Question 80

When you get the resultant X and the resultant Y, how do you find the magnitude of the resultant force?

Answer 80

use pythagorean theorem. R = sqrt (Fx^2 + Fy^2)

Question 81

cos 50 = sin __

Answer 81

40

Question 82

How is work different from power?

Answer 82

Work is force*distance, and power is an amount of work per unit of time. It is work/time. Power is a RATE OF DOING WORK, basically, how fast you can do the work.

Question 83

What weighs 1 N?

Answer 83

an apple

Question 84

What is the unit of power we use?

Answer 84

WATT (joule/sec) or (newton*meter/second)

Question 85

What is ENERGY?

Answer 85

Ability to do work. Like stored work.

Question 86

What is POWER? (two ways)

Answer 86

WORK/TIME or FORCE*DISTANC/TIME. It measures the rate of work, how fast you can do the work

Question 87

sin m = cos ___

Answer 87

90-m

Question 88

Where is the "opp" side?

Answer 88

If you imagine standing in a triangular room in the same corner as the angle. The opposite side is on the wall across the room from you.

Question 89

EQN relating change in PE to change in KE

Answer 89

mg(delta h)= 1/2 m(delta v)2

Question 90

What does the word "adjacent" mean?

Answer 90

It means "NEXT TO"

Question 91

How much energy in a 25kg block 4meters high?

Answer 91

PE= mgh = 25*10*4 = 1000 J

Question 92

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

Answer 92

It is so massive that it barely moves

Question 93

Explain FORCE units two ways

Answer 93

Newton or kg*m/s2

Question 94

if two objects have the same mass, the one with less velocity has _____ momentum

Answer 94

less

Question 95

What are other words for "UNTRIG?"

Answer 95

arctrig, or inverse trig. (arcsin, arctan, arccos or inverse sine, inverse tan or inverse cos)

Question 96

What does SOH CAH TOA stand for?

Answer 96

sin angle= opp/hyp cos angle = adj/hyp tan angle = opp/adj

Question 97

What is an elastic collision?

Answer 97

When all KINETIC energy is preserved (we solve problems like this, but in reality, energy is usually lost in sound and heat)

Question 98

sin 50 / cos 50 = tan ____

Answer 98

50