Gravity Unit Packet

Simple Machines Unit Packet

Name: ______Period: ______

Starter Questions: (3 points each)

(1 pointeach written item)

Main Principals of Simple Machines

1)Work is only done when the ______and ______are in the ______

______.

2)Power is only about ______work gets ______.

3)Simple machines work by ______or both of two main variables: ______&/or ______

4)As a result of the______, an ______occurs and work gets done on an object!

5)What we really want to do is get the ______as ______as possible.

6)______is all about getting the ______to make the job as ______as possible!

7)The ______the ______, the ______it is to accomplish the ______.

______

Vocabulary Terms you need for the test:

1)Work

Definition:

What is the formula for work:

What is the unit for work: ______

How much work is done if you push with a large amount of force, but no motion occurs?

2)Power

Definition:

Why does a power saw have more “power” than a hand saw?

What is the formula for power:What is the unit for Power: ______

3)Effort

Definition:

Give an example of using a machine to travel a distance with less effort than walking:

4)Machine

Definition:

Q: Why do we use machines?

A:

5)Input

Definition:Push or pull that ______to the machine

Give an example of a human using Input force:

6)Output

Definition:Push or pull ______on the object

Give an example of the output force from a machine as a result of a human’s input force:

7)Lever

Definition:

Draw a basic lever (Label the input and output sides):

8)Pulley

Definition:

Draw a basic pulley (Label the input and output sides):

9)Incline Plane (Ramp)

Definition:

Draw a basic ramp (Label the input and output sides):

10)Wedge

Definition:

Draw a basic wedge (Label the input and output sides):

11)Wheel & Axle

Definition:

Draw a basic wheel & axle (Label the input and output sides):

12)Compound Machine

Definition:

13)Efficient

Definition:

14)Mechanical Advantage

Definition:

What is the formula for MA:

Materials:

• stopwatch calculator
• stairs
• meter stick

Problem:

Can you change the amount of power you use while doing an exercise?

Procedure:

1)This lab will be performed on a single stair step.

2)Predict how your results will change if you step up and down at different speeds.

3)Measure the vertical distance in centimeters from the floor to the top of the step. Convert to meters by dividing by 100 and record this height in the data table.

4)Convert your weight from Pounds to Newton’s: multiply your weight(lbs) by 4.448 = N

5)Calculate the work you do in stepping up onto the step once. Record this in your data table.

6)Have one partner time how long it takes you to do 20 step repetitions performed at a constant speed. Count out loud to help the timer keep track of the number of repetitions. Record the time in your data table. (two feet up & two feet down = one repetition)

7)Calculate the Work and the Power in stepping up onto the step for 20 times “slowly”. Record your results in the data table.

8)Repeat Steps 5 thru 7, but climb the step “faster” than you did the first time. Record the new data in the data table.

9)Switch roles with your partners and repeat Steps 5 thru 7.

10)Record all your data in the data table.

Equations:

Work = Force x Distance (weight is a force & height is a distance)

Power = Work / Time

Predict:How will the power needed and the work performed change when you increase the speed of the repetitions of steps? (2 pts. each)

Power:

Work:

Data Table(1 point each for 36 pts. total)

Analyze and Conclude(2 pts each for 10 pts. total)

1. Compare the amount of work you did during your first and second trials.

Trial 1:Trial 2:

1. Compare the amount of power you produced during your first and second trials.

Trial 1:Trial 2:

1. Compare your results to your prediction: What was the same? What was different that you expected?

1. Describe the amount of effort required for the slow and fast tests:

1. Did you and your partners all do the same amount of work? Did you all produce the same amount of power? Explain your answers.

1)What is a good example of a simple machine you would find on a car?

2)What two things do simple machines help us change?

3)What does a pulley change?

4)A catapult is a good example of what kind of simple machine?

5)What do we call the middle of a lever?

6)What must you have in order to make a lever?

7)A ramp is used instead of a ladder because it spread what out?

8)If we use a ramp to raise a large object instead of picking it straight up, we would be using less what with the ramp?

9)A spiral staircase is a lot like what kind of simple machine?

10) What are some examples of what a screw can lift (jack)?

11) What makes the famous San Francisco streetcars go?

12)If a pulley can enable you to use ½ the normal effort to lift a load, what could you do if you only wanted to use ¼ the normal effort to do the same work?

Observe the cartoon on the next page. Identify each simple machine represented in the machine. Your choices of machines will be: Lever, inclined plane, pulley, wedge, screw, wheel & axel, and pendulum (not really a simple machine, but will be ok in this worksheet)

A. ______

B. ______

C. ______

D. ______

E. ______

F. ______

G. ______

H. ______

I. ______

J. ______

K. ______

L. ______

M. ______

N. ______

O. ______

P. ______

Levers are simple machines that consist of a rigid bar that is free to rotate around a fixed point. This fixed point is called a “fulcrum.”

There are three main types of levers:

First class:Second Class:Third Class:

Purpose:

In this lab you will be determining the actual mechanical advantage of levers when you adjust the fulcrum, mass and force.

Mechanical Advantage Equation:

MA= Output Force

Input Force

Materials:

-1 Meter stick-1 Fulcrum Stand

-1 500 g mass-2 Hanger Brackets

-1 20 N Force meter-1 Middle Bracket

Procedure:

1)Set up your machine as indicated by the diagrams (on the back side of this page).

2)Get your data

3)Repeat for all the rest of the setups.

4)Record all you data in the data table below:

Prediction: (2 pts. Each)

1) Which lever setup will give you the greatest mechanical advantage (predict)?

2) How many Newton’s (N) are required to lift a 500 gram mass: ______

3) What number represented a “basic” Mechanical Advantage?

First Class Lever(1 point each)

1)In order to make the MA “better”, what did you do with the fulcrum?

2)Which side of the lever had to be longer (Input or Output) for the “better” MA?

3)What happened to the MA when the Input side was SHORTER than the Output side?

Second Class Lever (use your finger to hold the lever on the fulcrum)(1 point each)

4)In order to make the MA “better”, what did you do with the position of the mass?

5)Which side of the lever had to be longer (Input or Output) for the “better” MA?

6)What happened to the MA when the Input side was SHORTER than the Output side?

Third Class Lever (use your finger to hold the lever on the fulcrum)(1 point each)

7)In order to make the MA “better”, what did you do with the position of the input effort?

8)Which side of the lever had to be longer (Input or Output) for the “better” MA?

9)What happened to the MA when the Input side was SHORTER than the Output side?

Purpose:

In this experiment, you will compare the effort required to move an object (as a result of Mechanical Advantage) up ramps of different slopes. You will also calculate the amount of work done by the ramps. What will the results be when you change the steepness and/or height of a ramp?

• Work:The result of a force being applied to an object and the measurement of the distance that

object has moved. ***Work is measured in joules.

Work (J) = Forcex Distance

• Mechanical Advantage: When the machine’s output force is greater than the Input force required to operate it. The work becomes easier to accomplish.***No unit for MA!!!

MA = Output Force/Input Force

Materials

• Short Ramp
• Long Ramp
• Wood Block
• Force Meter
• Calculator
• 3 Books
• Ruler/meter stick
• Counter edge

Procedures:

1. Pile 3 books high.
2. Lean the short board against the stack of books so that the board forms a ramp (inclined plane).
3. Measure from the end of the ramp to the bottom corner of the books and then the height from the base of the books to the top of the books. Record this data in your table.
4. Attach the wood block to your force meter, and then drag the block of wood up the ramp. Record the amount of Input force in your data table.
5. Repeat the experiment with the long ramp at the same height.Record this data in the table.
6. Calculate the mechanical advantage and work for ramp.
7. Repeat steps 2-6 for the experiment using the counter edge to rest your ramps against. The ramps will both be taller and steeper for these tests.
8. Answer thequestions that follow.

Predict:(2 points each)

1)What will happen to the amount of Input force needed to pull the block as the ramp gets steeper?

2)What will happen to the amount of work we accomplish when the ramp gets longer?

3 Book Test:(Have the top of the ramps as close to even with the top of books as you can)

Work accomplished during test:

Use the Work equation with the following as your variables: Output Force (N) x Height of Ramp (m) = Work

Short Ramp:

Long Ramp:

Edge of Counter test:(Have the top of the ramps as close to even with the top of counter as you can)

Work accomplished during test:

Use the Work equation with the following as your variables: Output Force (N) x Height of Ramp (m) = Work

Short Ramp:

Long Ramp:

Post Lab Questions: (2 points each)

1. What happened to your mechanical advantage when you used the longer (less steep) ramp?

1. Did the effort increase or decrease when the ramp was steeper? What if it was Taller?

1. What happened to the amount of work you accomplished when the ramp was steeper?

1. If we want to raise an object to a certain height; what would be the best solution? To use a longer ramp or a shorter ramp?

Pulleys are simple machines used to life objects vertically. A pulley consists of a rope wrapped around a wheel. There are three types of pulleys:

Fixed Pulley: Moveable Pulley:Block and Tackle:

Purpose:

In this lab you will be determining the actual Mechanical Advantage of all the types of pulley configurations.

Materials:

-single pulleys-1 Iron ring

-double pulleys-1 500 g mass

-1 string-1 20 N Force meter

-1 ring stand

Mechanical Advantage Equation: M.A. = Output Force

Input Force

Prediction: (2 pts)

Which pulley set-up will produce the highest Mechanical Advantage?

Procedure:

1)Find the Weight (N) of the 500 g mass by hanging it from the force meter: ______(1 pt)

2)Lift (Input) the 500 g mass 5 cm (Output) with the force meter.

3)Record the Output force, Input distance & Input force for each test.

4)To find the Input distance: measure the distance the black mark on the string moves. This is the Input distance. For all amounts in this lab, go ahead and round to the nearest whole number.

5)The ratio is how many times greater is the Input distance from the Output distance

Ex: 15 cm Input and 5 cm Output = 3:1 ratio (15 cm is 3 times greater than 5 cm)

6)Repeat the experiment for all configurations and record all data in the data table.

Data: (20 pts.)

Questions: (2 pts each)

1)What is the relationship between the weight of the mass and the input force on the single pulley system? How does this relate to the mechanical advantage?

2)As you added pulleys to the system, what happened to the amount of effort needed to raise the mass?

3)What is the relationship between the amount of pulleys you had and the ratio of input distance to output distance?

4)How did the number of pulleys used in the system effect the actual mechanical advantage?

5)Write a statement about the relationship between the distances the mass moved relative to the input distance the force meter moved.

1)The force you have to do to a machine is called:

Attempt: ______

Correct: ______

2)A more efficient machine will have a mechanical advantage of…

Attempt: ______

Correct: ______

3)Which of these tools would have a better (higher) Mechanical Advantage?

Attempt: ______

Correct: ______

4)What would the mechanical advantage of a machine be that had an output force of 24 N and an input force of 8 N?

Attempt: ______

Correct: ______

5)The force a machine will do as a result of what you did is called:

Attempt: ______

Correct: ______

6)What two things do machines do for us?

Attempt: ______

Correct: ______

7)Which side of the machine needs to be longer for a better mechanical advantage?

Attempt: ______

Correct: ______

8)Which ramp would have a better Mechanical Advantage?

Attempt: ______

Correct: ______

9)If the mechanical advantage of a machine is really low, what will the effort be like?

Attempt: ______

Correct: ______

10)Why would a car be considered to have more power than a bike?

Attempt: ______

Correct: ______

11)If the two ramps are the same length, what is wrong with choosing the shorter height ramp to get the job done instead of the taller ramp?

Attempt: ______

Correct: ______

12)“What was accomplished?” is another way to ask about what?

Attempt: ______

Correct: ______

Questions:

1. Identify the following terms on the diagram below:

1. Effort arm
2. Result arm
3. Input side
4. Input force
5. Output side
6. Output force

1. According to the diagram below, what happens to the amount of effort (Input force) I would need to apply if I moved the fulcrum to where the arrow indicates?

1. Calculate how much work (force x distance) is done on both sides of the lever:

1. Question: which following machine did more work on the object? (BE CAREFUL!!!)

1. If I was to make lifting an object with a lever EASIER to do (take less effort) what should I do with the fulcrum?

1. If I wanted to cut thick branches of a tree, which set of trimmers would I want to use? Write next to the correct picture one sentence explaining why:

AB

1. If all the shown masses are equal, which of these levers would have the greatest mechanical advantage?

1. Four levers were built and tested by lifting a large mass which required 4N to move. The effort needed for each is listed here:
2. Lever A = 0.5 N
3. Lever B = 1 N
4. Lever C = 2 N
5. Lever D = 4 N

Which lever had the greatest mechanical advantage?

1. What would the mechanical advantage of a pulley be if the output force was 12 N and an input force of 3 N?

MA =

1. What is the easiest way to increase the MA of a ramp?

1. Why don’t you want to change the height of a ramp when changing the length?

1. On the ramp diagram, if I were to increase the height of the ramp, how would that affect the amount of work I would have to do?

1. Identify the fulcrum point and where the input and output forces are.