Energy, Work, and Simple Machines

Question 1

Efficiency

Answer 1

Can be calculated by comparing a machine’s output work to its input work

Question 2

Machine

Answer 2

A device that changes the magnitude or the direction of a force

Question 3

Compound machine

Answer 3

Consists of 2 or more simple machines linked so that the resistance force of one machine becomes the effort force of the second machine

Question 4

Resistance force

Answer 4

the force exerted by a machine

Question 5

watt

Answer 5

a unit of power defined as 1 joule per second

Question 6

effort force

Answer 6

the force exerted by a person on a machine

Question 7

work-energy theorem

Answer 7

states that the work done on an object equals the change in kinetic energy of the object

Question 8

energy

Answer 8

the ability of an object to produce a change in itself or its surroundings

Question 9

kinetic energy

Answer 9

the energy that results from the motion of an object

Question 10

power

Answer 10

the rate of doing work

Question 11

mechanical advantage

Answer 11

the ratio of the resistance force of a machine to its effort force

Question 12

why is gasoline called a ‘miracle’ in the film

Answer 12

Gas is relatively cheap, it leaves no ash or residue, has a high yield

Question 13

joule

Answer 13

the SI unit used for work

Question 14

ideal mechanical advantage

Answer 14

calculated by comparing the effort distance to the resistance distance

Question 15

work

Answer 15

when an applied force is multiplied by the distance through which the force is applied

Question 16

What makes electric cars still expensive

Answer 16

Batteries are expensive

Question 17

What does the area under the force-displacement graph represent?

Answer 17

the work done on the object

Question 18

what are 2 major advantages of natural gas as an energy source compared to the other fossil fuels

Answer 18

Natural gas is less expensive
environmental friendly; burns cleaner

Question 19

What is the equation for finding work?

Answer 19

w = fd

Question 20

Work and energy are measured in?

Answer 20

Joules

Question 21

do you think nuclear power is a safe form of energy

Answer 21

it is very safe because they can withstand drastic weather and the plants are very secure

Question 22

Explain the relationship between work and energy

Answer 22

Energy is the ability to do work. When you do work to move an object, you’re changing the object’s energy

Question 23

What is the equation for finding power?

Answer 23

W/T or FD/T

Question 24

Power is measured in?

Answer 24

Watts

Question 25

Power can be described as..

Answer 25

the rate of energy transfer

Question 26

In what unit is work measured?

Answer 26

Joules

Question 27

what does the film say that you and I should do with the global energy demand

Answer 27

suggest nuclear, natural gas, and renewable energy be combined to see 50 year crossover.

Question 28

Which of the following is NOT a way to increase power

Answer 28

increase time

Question 29

why is the documentary called switch

Answer 29

because they are looking for ways to switch their prime,old fashioned energy sources to more environmental friendly and future ones

Question 30

Which of the following would produce the greatest increase in the kinetic energy of a moving object?

Answer 30

doubling its velocity

Question 31

what is not a part of the human body lever system

Answer 31

nerve fibers

Question 32

A baseball and a ping pong ball are both shot from a slingshot with equal velocity. Which object has the greater velocity?

Answer 32

The baseball, it has a greater mass

Question 33

A diver doing a somersault has a greater angular velocity in the

Answer 33

tuck position, is at more of an angle (i think..)

Question 34

when you use a hammer to strike a nail, what class lever is this

Answer 34

first

Question 35

How does the kinetic energy of a car traveling at 16 m/s compare with the kinetic energy of the same car traveling at 8 m/s?

Answer 35

it is 4 times greater (the velocity gets squared)

Question 36

when you use a hammer t remove a nail using the claw, what class lever is this

Answer 36

third

Question 37

machine

Answer 37

a device that changes the magnitude or direction of a force

Question 38

energy

Answer 38

the ability of an object to produce a change in itself or its surroundings

Question 39

How much work would have to be done on a truck with a kinetic energy of 2x10^4 J to reduce its kinetic energy by half

Answer 39

1 x 10^4

Question 40

kinetic energy

Answer 40

energy that results from motion of an object

Question 41

potential energy

Answer 41

energy of storage due to its position relative to other objects

Question 42

A car has a kinetic energy of x J 7.5 s later it moves in the opposite direction with the same speed. What kinetic energy does it have?

Answer 42

xJ

Question 43

power

Answer 43

the rate of doing work

Question 44

hydrothermal and geothermal

Answer 44

this type of energy is created by hot spots; areas where earth's core heat comes to surface

Question 45

A car has a kinetic energy of x J 7.5 s later it moves in the opposite direction with 3 times its initial speed. What kinetic energy does it have?

Answer 45

9x, velocity is squared

Question 46

A 6kg ball is travelling at 5m/s, what is its kinetic energy?

Answer 46

75 J

Question 47

hydroelectric

Answer 47

if an area has flowing water and has the money to build a damn to connect it to the electricity grid, then they can use this form of renewable energy

Question 48

If the velocity of the ball in question 16 doubles, its kinetic energy will be..

Answer 48

300 J

Question 49

Biomass

Answer 49

This source can be made from scraps of plant, grain, wood, and other types of biological material; it converts a solid to a liquid form to use instead of gas in vehicles

Question 50

nuclear energy

Answer 50

this type of energy relies o stellar energy; splitting of heavy atoms and the combining of lighter ones

Question 51

Waves

Answer 51

This type of energy is produced when electricity generators are placed on the surface of the ocean. The energy provided is most often used in desalination plants, power plants, and water pumps.

Question 52

wind turbines/ generators

Answer 52

this type of energy is used throughout areas of the midwest and in the southern regions of the U.S and can be a way to generate power to large areas in a fairly inexpensive way

Question 53

Conventional Batteries

Answer 53

This source of energy is largely used for powering low voltage devices that are not used often. Its life and endurance is dependent on the apparatus it will energize and the chemical agent involved in its makeup

Question 54

hydrogen fuel cells

Answer 54

this source is often compared to batteries; both convert the energy produced by a chemical reaction into usable electric power

Question 55

Indirect Natural Gas

Answer 55

Converting landfill gasses into a source of renewable energy is beneficial because it reduces greenhouse-gas emissions and can generate revenue from the sale of the electricity

Question 56

solar cells

Answer 56

this device absorbs light energy from the sun and converts it into usable forms of energy

Question 57

Standard Electrical Power

Answer 57

This type of energy is significant because our society uses large amounts of it and it depends on the use of power plants that convert some other kind of energy into it.