Physics Study Guide Chapter 9

Front 1

define machine

Back 1

a device that multiplies the forces in a system and changes the direction

Front 2

what are the 2 types of work and how do they relate to force or distance?

Back 2

the work input and the work output

Front 3

how is work conserved with a machine?

Back 3

machines don't increase the work put in, but work that comes out cannot be more than the work put in. the work that goes into the machine is different than the work that comes out of the machine because it has been transformed

Front 4

define efficiency

Back 4

how well a machine does it's job- it is a comparison of the work in and the work out

Front 5

why are there no 100% efficient machines?

Back 5

efficiency can never be greater than the work input. more friction means less efficiency

Front 6

how do you calculate efficiency?

Back 6

efficiency=work input / work output

Front 7

define mechanical advantage

Back 7

the number of times a machine multiplies the effort force

Front 8

list the 6 types of simple machines

Back 8

screw, lever, pulley, inclined plane, wheel & axel, wedge

Front 9

define the 6 types of simple machines

Back 9

wedge- an inclined plane that moves

screw- an inclined plane wrapped around a bar or cylinder to form a spiral

lever- a rigid bar that is free to pivot around a fixed point

pulley- a rope, belt, or chain wrapped around a grooved wheel

wheel & axle- 2 circular objects of different sizes, wheel is larger than axle

Front 10

describe the three types of levers based on the fulcrum

Back 10

TYPE 1- the fulcrum is between the load and the effort

TYPE 2- the fulcrum is on one side with the load in the middle and the effort on a side

TYPE 3- the fulcrum is on one side and the effort is in the middle and the load is on the other side

Front 11

a zipper is an example of which simple machine?

Back 11

a wedge

Front 12

a staircase is an example of which simple machine?

Back 12

an inclined plane

Front 13

A propeller is what type ofsimple machine?

Back 13

A WHEEL AND AXLE

Front 14

A seesaw is an example ofwhat specific type of machine?

Back 14

a lever 1st class

Front 15

Tweezers are an example whatspecific type of machine?

Back 15

3rd class lever

Front 16

Compare and contrast:movable and fixed pulley.

Back 16

both pulleys are a part of a block and tackle system, they both change the direction of the load. one is attached to a structure one is not

Front 17

Compare and contrast: 1st,2nd and 3rd class levers.

Back 17

same as #9 for differences. the same is that they are all simple machines that are levers & they all make work easier

Front 18

what is a block and tackle system?

Back 18

a combination of movable and fixed pulleys that form one system

Front 19

Define compound machine.

Back 19

a machine that uses two or more simple machines

Front 20

Name 3 simple machines thatwork together to make a bulldozer.

Back 20

lever for the gear shift. inclined plane on the scoop. wheel and axle on the steering wheel

Front 21

Who was Rube Goldberg andwhy did he draw his cartoon machines?

Back 21

rube Goldberg is the inventor/ namesake of the rube Goldberg machine. he drew his designs because he was an artist that was pressured to be an engineer.