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Simple Machines and Energy > Basics > Flashcards

Basics Flashcards

1
Q

What is force measured in?

A

Force is measured in newtons/(N)

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2
Q

What is mass measured in?

A

Mass is measured in kilograms (kg)

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3
Q

How much is one kilogram in grams?

A

1 kg = 1000 gr

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4
Q

What is air resistance?

A

Air resistance is a force that acts in the opposite direction on an object when it travels through the air. Basically, air pushes against a moving object. It’s a kind of frictional force.

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5
Q

What is friction?

A

Frictional force is the opposing force that is created between two surfaces that try to move in the same direction or that try to move in opposite directions. The main purpose of a frictional force is to create resistance to the motion of one surface over the other surface.

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6
Q

What is gravitational force?

A

It is an invisible force that pulls objects toward each other - the force of attraction on a body by earth. The acceleration of gravity is 9.8m/s^2. Objects with more mass have more gravity. Gravity also gets weaker with distance. So, the closer objects are to each other, the stronger their gravitational pull is.

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7
Q

What is velocity?

A

Velocity is quickness of motion or action. An example of velocity is a car driving at 75 miles per hour. Velocity = distance/time. “Speed in a given direction.”

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8
Q

What is force?

A

A force is a push or pull upon an object resulting from the object’s interaction with another object. Whenever there is an interaction between two objects, there is a force upon each of the objects. … Forces only exist as a result of an interaction.
Force = Mass x Acceleration.
It’s measured in Newtons (N).

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9
Q

What are the 1 of 3 of Newton’s laws of motion?

A
  1. If all the forces acting on an object are balanced there will be no acceleration = either constant velocity or an object remaining stationary.
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10
Q

What are balanced forces?

A

Take a horse. There’s a force of gravity; acts towards the center of earth. The size of the force of gravity is the horse’s weight. An arrow is drawn downwards - horse to earth. Because there’s another force at play (opposing the force of gravity) = the reaction force pointing upwards. The arrows are the same size, thus they are a balanced pair of forces.

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11
Q

What, other than gravity/reaction forces are at play regarding the horse? (balanced, unbalanced, resisting forces)

A
  1. Driving force; this force is opposed by a force trying to slow it down. If the horse is travelling at a constant velocity, the force of friction + air resistance are equal in size, but opposite in direction of the driving force. The driving force is now balanced by the two forces. Due to this, the horse travels at a constant velocity.
  2. If the horse accelerates, the driving force must be greater than friction + air resistance. The driving force is now no longer balanced by the two resisting forces, thus the forces are now unbalanced.
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12
Q

Simply put: balanced forces

A

If an object is balanced (has an equal amount of driving force/resisting forces) it remains stationary or goes on, at a constant velocity.

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13
Q

Simply put: unbalanced

A
  • It will accelerate/decelerate; increase/decrease in velocity
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14
Q

How to calculate efficiency?

A

Efficiency = useful work output/work input x 100

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15
Q

The pyramid equation

A

Weight (N) = mass (kg) x g (N/kg)
Mass = weight/g
g (acceleration of gravity)= weight over mass

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16
Q

A matchstick has a mass of 3g on Earth. Calculate the weight of the matchstick.

A

N = m x g
Therefore, weight = 3 x 9.8
= 29.4 g

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17
Q

An object has a weight of 30kN. The gravitational field strength is 8.3 N/kg. Calculate the mass of the object.

A 
N = m x g
1kN= 1000 N
m = kN/g
m = 30 000 x 8.3
m = 249.000
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18
Q

If you dropped a hammer and a feather on the moon, which one would hit the ground first?

A

The moon is a vacuum: there is no air on it. Because of this, there is no air resistance. Because of this, both objects experience no resistance when they fall and fall on the same time.
Objects with more mass or density fall faster than the opposite.
Gravity accelerates both objects at the same rate. but the feather is more slowed down bc of air resistance.

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19
Q

An elephant with mass of 5000 kg on the moon where g is 2 N/kg. What is its weight?

A

Weight = m x g

Therefore, 5000 x 2 = 10 000

20
Q

A pølse with mass of 0.2kg on Jupiter where g is 25 N/kg. What is its weight?

A

Weight
= m x g
Thus, 0.2 x 25 = 5

21
Q

A Jello weighing 1N on planet Olderon where g is 0.8 N/kg. What is its mass?

A

N = m x g
Therefore, N/g = m
1/0.8
m = 1.25

22
Q

A frikadelle on Zoth has a mass of 0.2kg and weighs 50N. What is Zoth’s g (gravitational field strength)?

A 
N = m x g, therefore g = N/m
50N/0.2 = 250
23
Q

What is acceleration?

A

Is when velocity changes with respect to time.

For example slowing down, speeding up or changing direction.

24
Q

If I’m slowing down, that means (acceleration)…

A

I’m encountering either:
Negative acceleration and positive velocity
OR
positive acceleration and negative velocity
Signs point opposite ways

25
Q

If I’m speeding up that means (acceleration)..

A

I’m encountering either:
Positive acceleration and positive velocity
OR
Negative acceleration and Negative velocity
Both signs point the same way

26
Q

What are the 8 types of energy?

(GRENCEKT)?

A
  1. Gravitational potential
  2. Radiated
  3. Elastic
  4. Nuclear potential
  5. Chemical
  6. Electrical
  7. Kinetic
  8. Thermal
27
Q

What’s a rule of thumb for energy in the universe?

A

Energy cannot be created nor destroyed. It is only transformed from one form or energy to another.

28
Q

Define: Potential energy

A

When something has the potential to move, it has potential energy.

29
Q

What happens when motion occurs to potential energy?

A

PE => kinetic energy when motion occurs

30
Q

The more _ you have, the more KE

A

Mass

31
Q

The _ , the more potential energy you’ve got

A

The ‘higher you go’

32
Q

What’s the thing about mass and weight?

A

Mass stays the same wherever you are. On the moon, on mars, anywhere. Weight differes per the gravitational pull of where you are. Fx, on the moon you weigh less but behold the same mass.
Think of it like this: mass = the meat on your bones
weight = a societal measurement to discriminate against you
The moon don’t discriminate!

33
Q

What’s up with the 1st class lever?

A

On god bro! So basically in this b, the pivot/fulcrum’s in the middle. Maddy, if you’re watching this, fulcrum’s the superior word!

34
Q

Then.. what about the 2nd class lever?

A

These are bad bleeps. Fr, the LOAD is in the middle on these bruh! The LOAD! also known as the box or whatever you’re trying to lift. Yk, the output work.

35
Q

Noice. 3rd class lever?

A

Finally g! My fave! The effort’s in the middle. The action of doing the deed. You buying flowers for your girlfriend. Me pressing the toothpaste out the tube. Yk, the input work. The stuff you put in. Where your heart lies.

36
Q

Cool now draw a sankey diagram with this info: energy input ( 200 J), sound energy (70 J), heat energy (130 J)

A

Bruh

37
Q

Wazup with dat pulley

A

Dat pulley? Bro have some more respect bro.
Anyway.
Pulley - a wheel with a grooved (tf) rim around which a cord passes, which acts to change the direction of a force applied to the cord, and is used to lift heavy weights.

38
Q

Draw me a fixed pulley

A

It’s the simple one. Just one wheel, it goes up, then around the wheel, then down. So the effort points downwards.

39
Q

Draw me a moveable asf pulley

A

Ok this pulley hangs from the ceiling or sum? Sia vibes who?

Lmao anyway so the effort starts from upstairs, goes down around the wheel and then uppity again.

40
Q

COMBINED PULLEYYEYYEY

A

She’s wonderful.
2 wheels at the same time. We start from upstairs, go down round wheel 1, go up again to move to wheel 2, go around her and then down again. So the effort at the end’s looking down innit.

41
Q

So… what’s up baby output work?

A

Don’t you know me?
I’m the work done to lift a weight to a certain height. I’m weight (N) x height (m)
you can’t touch this.

42
Q

Okay then input work? Sharty?

A

Did you just call me sharty? The audacity..
I’m literally the amount of work you have to do to pull the object up the ramp. I’m force (N) x Length of ramp (m)
Your mom could never

43
Q

Whatever. What’s up whichu, ramp?

A

Did you just call me trampetøs?
Just because I wear black jackets and my grammar is ass..

I’m literally an inclined plane. Like a lever, I lower the force you need to lift something by spreading the work over a longer distance.
I am also the efficiency of me (the ramp) depends on:
The friction between the ramp and the object
The angle of the ramp

44
Q

Define work done

A

Work done is when a force moves. Hallelujah.
Okay okay some more info:
work done is the amount of energy transferred when a force is applied over a specific distance. It is measured in J (Joules).

45
Q

Wait, the ramp does not do work for you? Elaborate.

A

When you use a ramp to raise an object, the total work done is the same as before.
- The ramp does not do work for you.
BUT - the force needed to pull the object up the ramp to the same height off the ground is LOWER because you are pulling the object over a greater distance.
So in this case:
Work (same as before) = force (the force needed to pull the object up the ramp is lower than the weight) x distance (the length of the ramp is longer than the height)

46
Q

The shorter the lever, the _

A

The less energy is needed

Simple Machines and Energy (6 decks)

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