# ch 12-13 Flashcards Preview

## Sci 7th grade > ch 12-13 > Flashcards

Flashcards in ch 12-13 Deck (47)
1
Q

work

A

when you exert a force on an object that causes the object to move some distance

2
Q

how do you know if work is being done on an object

A

if an object moves in the same direction in which the force is exerted

3
Q

joule

A

measurement for work, 1 joule is to move an object a distance of one meter

4
Q

power

A

the rate at which work is done

5
Q

a machine makes work easier by changing at least one of three factors, what are the three factors

A

a machine may change the amount of force you exert, the distance over which you exert your force, or in the direction in which you exert your force

6
Q

machine

A

a device that allows you to do work in a way that is easier

7
Q

input force

A

the force you exert on the machine

8
Q

input distance

A

the distance the input force moves the machine

9
Q

output force

A

the force the machine exerts on an object

10
Q

output distance

A

the work the machine dose over another distance

11
Q

input work

A

the input force times the input distance

12
Q

output work

A

the output force times output distance

13
Q

A

the number of times a machine increases a force exerted on it

14
Q

efficiency

A

compares the output work to the input work of machine

15
Q

what are the six basic types of simple machines

A

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

16
Q

most of the machines in your body are what?

A

levers that consist of bone and muscles

17
Q

what is the ideal mechanical advantage of a compound machine

A

it is the product of the individual ideal mechanical advantages that make it up

18
Q

incline plane

A

a flat, slope

19
Q

wedge

A

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

20
Q

screw

A

can be thought of as an incline plane wrapped around a cylinder

21
Q

lever

A

is a ridged bar that is free to pivot or rotate on a fixed point

22
Q

fulcrum

A

the fixed point that a lever pivots around

23
Q

wheel and axle

A

a simple machine made out of two circular or cylindrical objects fasted together that rotate about a common axis

24
Q

pulley

A

a simple machine made of a grooved wheel with a rope or cable rapped around it

25
Q

compound machine

A

a machine that utilizes two or more simple machines

26
Q

what are two basic types of energy

A

kinetic and potential

27
Q

energy

A

the ability to do work or cause change

28
Q

kinetic energy

A

the energy an object has due to its motion

29
Q

potential energy

A

stored energy that results from the position or shape of an object

30
Q

gravitational potential energy

A

potential energy related to an objects hight

31
Q

elastic potential energy

A

the potential energy associated with objects that can be stretched or compressed

32
Q

what are forms of energy that are associated with particles of an object

A

thermal energy, electrical, energy chemical energy nuclear energy, electromagnetic energy

33
Q

mechanical energy

A

energy associated with the position and motion of an object

34
Q

thermal energy

A

the total potential and kinetic energy of the particles in an object

35
Q

electrical energy

A

the energy of electric charges

36
Q

chemical energy

A

potential energy stored in chemical bonds that hold chemical compounds together

37
Q

nuclear energy

A

a type of potential energy that is stored in the nucleus of an atom

38
Q

electromagnetic energy

A

waves that have some electrical and magnetic properties

39
Q

what is the most common energy transformation between

A

kinetic and potential

40
Q

energy transformation

A

a change from one form of energy to another

41
Q

law of conservation of energy

A

states that when one form of energy is transferred to another, no energy is destroyed in the process

42
Q

matter

A

is anything that has mass and takes up space

43
Q

fossil fuels contain energy that came from what?

A

the sun

44
Q

fossil fuel can be burned to release what type of energy?

A

chemical energy

45
Q

fossil fuel

A

fuels made from materials that formed hundreds of millions of years ago.

46
Q

what are some examples of fossil fuel

A

coal, petroleum, and natural gas

47
Q

combustion

A

the the process of burning fuels