Forces And Energy Chapter 3

Front 1

what is the term for the rate at which work is done?

Back 1

power

Front 2

what is definition of a machine?

Back 2

a device with which you can do a certain amount of work in a way that is easier or more effective than if you did not use a machine

Front 3

what are 3 ways that a machine may make work easier, and give an example of each way?

Back 3

1.) a machine makes work easier by changing the amount of force you exert, the distance over which you exert your force, or the direction in which you exert you force.

2.) multiplying either force or distance or by changing the direction of the force

3.)

Front 4

describe what mechanical advantage is

Back 4

the number of times a force exerted on an machine is multiplyed by the machine

Front 5

if a machine has a mechanical advantage of 1, what does that mean

Back 5

it means that the input force is the same as the output force

Front 6

what doe it mean if a machines M.A is greater than 1?

Back 6

the output force is greater than the input force

Front 7

what does it mean if the machines M.A is less than 1?

Back 7

the output force is less than the input force

Front 8

the more efficient a machine is, the closer the A.M.A gets to what?

Back 8

A.M.A = actual mechanical advantage

the more efficient the machine the closer the A.M.A is to the I.M.A

Front 9

what is an inclined plane?

Back 9

a flat, slanted plane

Front 10

what is a wedge?

Back 10

a device that is thick at one end and tapers to a thin edge at the other end

Front 11

what is the difference between a wedge and inclined plane?

Back 11

Its like an inclined except in the case of a wedge, you use it by moving the inclined plane itself

Front 12

what is a screw?

Back 12

an inclined plane wrapped around a central cylinder, forming a spiral. This spiral forms the threads of the screw

Front 13

what is a lever?

Back 13

a ridged bar that is free to pivot around a fixed point

Front 14

what determines what class of lever a machine will be?

Back 14

Levers are classified according to the location of the fulcrum relative to the input and output forces

Front 15

describe each class of lever and give an example for each

Back 15

-First class levers have the fulcrum between the input and output forces (ex: seesaw, paint can opener)

- Second class levers have the fulcrum at one end, the input force at the other end, and the output force in the middle (wheel barrow)

-Third class levers have the fulcrum at one end, the output force at the other end, and the input force in the middle (hockey stick, lower arm)

Front 16

describe what a wheel and axle is

Back 16

a simple machine of 2 circular or cylindrical objects that are fastened together and rotate around a common axis.

Front 17

what is a pulley?

Back 17

a rope or chain that is wrapped around a grooved wheel

Front 18

what is the difference between a fixed and movable pulley?

Back 18

A pulley that you attach to a structure is called a fixed pulley. If you attach a pulley to the object you wish to move, you are now using a movable pulley.

Front 19

what is the term for a system of fixed and movable pulleys moving together?

Back 19

block and tackle

Front 20

what are the 6 types of simple machines?

Back 20

inclined plane, wedge, screw, lever, wheel and axle, pulley

Front 21

how does a compound machine work?

Back 21

the output force of one machine becomes the input force of another machine