Simple Machines

Question 0

True or false

Applying a force always results in work being done

Answer 0

False, the object has to move

Question 1

Define work

Answer 1

In science, work occurs when a force causes an object to move in the direction of that force

Question 2

When do you know if work is being done

Answer 2

1) the object moves as a force is applied

2) the direction of the objects motion is the same as the direction of the force applied

Question 3

Work formula & what is the unit for work

Answer 3

W=FxD

Joules

Question 4

Define power

Answer 4

The rate at which work is done.

Question 5

Power formula & what is the unit for power

Answer 5

P=W divided by T

Watt

Question 6

How is powered increased

Answer 6

When work is done faster

Question 7

Define machine

Answer 7

A device that helps make work easier by changing the size or direction or a force

Question 8

Define input force

Answer 8

The work you do on the machine

Question 9

Define output force

Answer 9

The work done by the machine

Question 10

True or false

Work output can never be greater than the work input

Answer 10

True

Question 11

What is the force-distant trade off

Answer 11

When you increase force you decrease distance and when you increase distance you decrease force

Question 12

Define mechanical advantage

Answer 12

Tells you how many times the machine multiplies force.

Question 13

Equation for mechanical advantage

Answer 13

Output force divided by input force

Question 14

Why can work output never be greater than work input.

Answer 14

Because some of the work is used to overcome friction, but no work is lost

Question 15

Define mechanical efficiency

Answer 15

A comparison of a machines work output and work input

Question 16

Equation for mechanical efficiency

Answer 16

Work output divided by work input. Then multiplied by 100

Question 17

6 simple machines

Answer 17

Lever, inclined plane, wedge, screw, pulley, wheel & axle

Question 18

Define lever

Answer 18

Simple machine consisting of a bar that pivots at a fixed point

Question 19

Explain 1st class levers

Answer 19

The fulcrum is in the middle. Always changes the direction of the of the input force. Ex. Seesaw

Question 20

Explain 2nd class levers

Answer 20

The load is in between the fulcrum and the input force. They allow you to apply less force than the force exerted by the load. Ex. wheelbarrow

Question 21

Explain 3rd class levers

Answer 21

The input force is between the load and the fulcrum. The output force is less than the input force

Question 22

Define inclined plane

Answer 22

Simple machine that is in a straight slanted surface

Question 23

Equation for M.A for inclined plane.

Answer 23

Length divided by height

Question 24

Define wedge.

Answer 24

A doubled inclined plane that moves

Question 25

What happens when you move a wedge through a distance

Answer 25

It applies a force on an object. a wedge applies a output force that is greater than your input force but you apply the in the input force over a greater distance

Question 26

M.A of wedge

Answer 26

Length divided by it's greatest thickness

Question 27

Define screw

Answer 27

An inclined plane that is wrapped in a spiral

Question 28

M.A of a screw

Answer 28

The closer/ more spiral the screw has the greater the MA

Question 29

Define wheel & axel

Answer 29

A simple machine consisting if two circular objects of different sizes

Question 30

Which has a smaller radius a wheel or a axel

Answer 30

Axel

Question 31

I'm wheels and axels is there a larger output force than input force. If so why

Answer 31

Yes bc the axel is smaller so it rotates through a smaller distance

Question 32

MA of wheels and axel

Answer 32

Radius of wheel divided by the radius of the axis. Always greater than 1

Question 33

Define pulley

Answer 33

A simple machine consisting of a grooved wheel that holds a rope or cable.

Question 34

Describe Fixed pulley

Answer 34

A pulley that change the direction of the force. They don't increase force and is attached to something that doesn't move.

Question 35

Describe movable pulleys

Answer 35

Attached to something that can be moved. They don't change a forces direction. They increase force

Question 36

Describe block & tackles

Answer 36

A fixes pulley and a movable pulley together l. They can have a large mechanical advantage if several pulleys are used. MA found by counting rope segments

Question 37

Define compound machines

Answer 37

Machines that are made of two or more simple machines