work and energy

Question 1

what is work

Answer 1

force x distance; force exerted over a distance

Question 2

what must and object do in order for work to be occurring

Answer 2

moves in same direction as force

Question 3

what is energy

Answer 3

ability to cause work; make change

Question 4

what are the units of energy

Answer 4

joules

Question 5

what is potential energy

Answer 5

energy of position; stored energy

Question 6

what is kinetic energy

Answer 6

energy of motion

Question 7

what type of energy transfer happens when a ball is thrown in the air

Answer 7

kinetic-potential-kinetic

Question 8

or a ball thrown from the quarterback to the wide receiver

Answer 8

kinetic

Question 9

what kind of energy does a ball rolling across the floor have

Answer 9

kinetic

Question 10

describe the change between potential and kinetic energy when a person jumps on a trampoline

Answer 10

start- potential as you go up in the air, changes to kinetic, at top of jump-potential fall back down, changes to kinetic

Question 11

describe the energy transformations that occur in the following:

a: turning on a lamp
b: burning a piece of paper
c: eating an apple
d: sitting by a campfire

Answer 11

a- electrical ➢ mechanical
b- chemical ➢ radiant/heat
c- chemical ➢ mechanical ➢ heat
d- nuclear ➢ electrical ➢sound

Question 12

describe the law of conservation of energy

Answer 12

energy can never be created or destroyed; only transformed; total amt. of energy in the universe stays the same

Question 13

explain why all mechanical systems require an outside energy source to maintain their motion

Answer 13

energy gets used to overcome friction lost as heat