Chapter 4 Sections 2 and 3

Question 1

energy is the ability to…

Answer 1

cause change/ do work

Question 2

a system is anything around which you can ______

Answer 2

imagine a boundary

Question 3

What happens when one system does work on another system

Answer 3

energy is transferred from the 1st to the 2nd

Question 4

What are the 4 different forms of energy (2 extra)

Answer 4

chemical
mechanical
electrical
radiant
(sound)
(thermal)

Question 5

what is chemical energy

Answer 5

anything that can produce energy

Question 6

what is mechanical energy

Answer 6

something moving

Question 7

what is radiant energy

Answer 7

light

Question 8

is energy from the sun and energy from the food you eat the same

Answer 8

yes but different forms

Question 9

kinetic energy is the energy due to _____

Answer 9

motion

Question 10

what is the formula and unit for kinetic energy

Answer 10

KE = 1/2 m v^2
joules

Question 11

what are the 2 variables you must know to calculate kinetic energy

Answer 11

mass
velocity

Question 12

potential energy is energy that is _____ due to the …

Answer 12

stored
interactions between objects

Question 13

other names for potential energy

Answer 13

stored energy
energy at rest
energy of position

Question 14

elastic potential energy is the energy that is _____ by _____ an object

Answer 14

stored
compressing or stretching

Question 15

chemical potential energy is energy that is due to _____

Answer 15

chemical bonds

Question 16

gasoline and the food you eat have stored energy, where is this stored energy?

Answer 16

chemical bonds between atoms

Question 17

gravitational potential energy is energy of _____ and _____

Answer 17

position
mass

Question 18

what is the formula for gravitational potential energy

Answer 18

GPE = m g h

Question 19

what three variables must you know to calculate GPE

Answer 19

mass
gravity
height (above ground)

Question 20

can a system have kinetic energy and potential energy at the same time

Answer 20

yes
if something in the system is moving

Question 21

The different molecules that make up the air in a room have, on average, the same kinetic energy. How does the speed of the different molecules that make up the air depend on their masses?

Answer 21

in order for their KE to be equal, the smaller molecules (less mass) must travel faster than the larger molecules (more mass)

Question 22

the law of conservation of energy states that energy…

Answer 22

cannot be created or destroyed, but energy can change into other forms

Question 23

mechanical energy is the…

Answer 23

sum of the kinetic energy and potential energy of the objects in a system

Question 24

What is the formula for mechanical energy

Answer 24

ME = KE + PE

Question 25

when an apple falls from a tree what does it lose and what does it gain

Answer 25

gravitational potential force kinetic energy

Question 26

mechanical energy includes what kind of energy

Answer 26

kinetic energy and potential energy

Question 27

can potential energy be converted into kinetic energy

Answer 27

yes

Question 28

if some potential energy in a system is converted to kinetic energy, would the amount of mechanical energy remain the same

Answer 28

yes

Question 29

if mechanical energy is conserved, why does a person on a swing en=ventually come to a stop?

Answer 29

the energy from the swinging gets transferred due to friction ex. into sound

Question 30

a lightbulb is a device that transforms _____ energy into _____ energy

Answer 30

electrical radiant

Question 31

fuel stores energy in the form of _____ potential energy

Answer 31

chemical

Question 32

a car engine transforms chemical potential energy into _____ energy and then into _____ energy. also _____ energy

Answer 32

thermal mechanical sound

Question 33

every green plant converts _____ energy into _____ energy

Answer 33

radiant chemical potential

Question 34

power is the rate at which...

Answer 34

energy is converted

Question 35

energy from food is often measured in

Answer 35

calories

Question 36

every gram of fat you eat supplies the body with about __ calories

Answer 36

10

Question 37

every gram of protein you eat supplies the body with about __ calories

Answer 37

5

Question 38

every gram of carbohydrate you eat supplies the body with about __ calories

Answer 38

5

Question 39

what is the formula for power

Answer 39

P = E/t or w/t (Joule/second)

Question 40

the standard unit used to measure power is the _____

Answer 40

watt (W)

Question 41

What are the other units for power and when are they used

Answer 41

British thermal units (Btu): energy of heater, hot water heater, or AC horsepower (HP): the power an engine produces

Question 42

1Btu = _____ watts

Answer 42

1055

Question 43

1 HP = _____ watts

Answer 43

746