Flash Card #10

Question 1

What is work?

Answer 1

when the object moves in the same direction in which the force is exerted.

Question 2

What is the formula for work?

Answer 2

Work=ForcexDistance

Question 3

What is power?

Answer 3

The amount of work done on an object in a unit of time.

Question 4

What is the formula for power?

Answer 4

Power=Work over Time

Question 5

What is a machine?

Answer 5

is a device that allows you to do
work (Wi) easier or more effectively.

Question 6

What are the three factors that make machines work easier?

Answer 6

1] the amount of force you exert (input force, Fi)
2] the distance over which you exert your force
(input distance, Di)
3] the direction in which you exert your force
(input direction)

Question 7

What is the formula for machines?

Answer 7

W = F x D

Question 8

What are levers?

Answer 8

rigid bar that pivots/rotates on a fixed
point.

Question 9

What is a fulcrum?

Answer 9

fixed point that a lever pivots
around.

Question 10

How do machines work?

Answer 10

Fi x Di = Fo x Do where i= input, o = output
Fi = Fo x Do
Di = Fo x Do
Di
Fi
Fo = Fi x Di
Do = Fi x Di
Do
Fo

Question 11

What is mechanical advantage?

Answer 11

the number of
times a machine increases the input force (Fi).
MA = Fo
Fi

Question 12

What is efficiency?

Answer 12

compares output work to input work.
An ideal machine’s efficiency = 100%. A real
machines efficiency is less than 100% because
some output work (Wo) is lost due to friction (heat
loss).
Efficiency = W0 x 100 = ______ %
Wi

Question 13

What is a wheel and Axle?

Answer 13

two circular/cylindrical objects
that are connected together and rotate around
a common axis, where:
Wheel: larger radius object
Axle: smaller radius object

Question 14

What is a pulley?

Answer 14

a grooved wheel with a rope (cable)
wrapped around it.

Question 15

What are the types of pulleys?

Answer 15

Fixed Pulley, Movable Pulley and Block & Tackle

Question 16

What is a fixed pulley?

Answer 16

pulley attached to a structure
(ceiling, wall). Fi = Fo , change in direction; MA = 1

Question 17

What is a movable pulley?

Answer 17

pulley attached to moving object.
increase Fo , no change direction; MA = 2

Question 18

What is a block and tackle?

Answer 18

fixed & movable pulley system.
increase Fo , no change direction; MA = varies

Question 19

What is a compound machine?

Answer 19

a combination of two or
more simple machines.

Question 20

What is energy?

Answer 20

ability to do work

Question 21

What is chemical energy?

Answer 21

from chemical bonds

Question 22

What is electrical energy?

Answer 22

moving electrons

Question 23

What is mechanical energy?

Answer 23

moving things (parts)

Question 24

What is heat energy?

Answer 24

moving molecules

Question 25

What is nuclear energy?

Answer 25

from atom’s nucleus

Question 26

What is light(solar) energy?

Answer 26

moving photons

Question 27

What is sound energy?

Answer 27

vibrating objects

Question 28

What is potential energy?

Answer 28

stored energy

Question 29

What is kinetic energy?

Answer 29

motion energy

Question 30

What is the formula for potential energy?

Answer 30

Stored energy; energy of position PE = weight (mass) x height

Question 31

What is the formula for kinetic energy?

Answer 31

motion energy KE= 0.5 mass x velocity2 Potential (work) Kinetic Work (joule) = Force (newton) x Distance (meter)

Question 32

What are renewable resources?

Answer 32

are materials that can be replaced at the rate at which we use them.

Question 33

What are non-renewable resources?

Answer 33

are materials that can not be replaced at the rate at which we use them.