Physics final review

Question 1

what must happen to all potential energy before it becomes useful

Answer 1

conversion to kinetic energy

Question 2

why do objects at rest not move

Answer 2

because all forces acting on them are balanced

Question 3

how can an object gain motion

Answer 3

if forces become unbalanced (one force is greater than another), then an object can gain motion

Question 4

force:

Answer 4

a push or a pull on an object.
F=ma

Question 5

net force:

Answer 5

an object has many forces acting upon it; the sum of these forces is called the netforce
F=ma

Question 6

the effect of mass:

Answer 6

a factor that influences the rate of acceleration/deceleration of an object

Question 7

force and work:

Answer 7

when a force is applied to an object, causing that object to move, then work is done on the object.

• object must move in order for work to be done

Question 8

how to get the work from a force and distance graph

Answer 8

-area
force x d

Question 9

energy:

Answer 9

-the ability to do work
-if an object has energy, then it can do work by transferring that energy to another object
- all physical processes involve the transformation of one type of energy into another

Question 10

what are the types of energy

Answer 10

potential(position) and kinetic (motion)
- further energy types under these
two catagories

Question 11

types of potential energy

Answer 11

• electrical
• chemical
• gravitational
• nuclear
• elastic
• thermal

Question 12

types of kinetic energy

Answer 12

• thermal
• sound
• radiant
• elecrical
• mechanical

Question 13

kinetic energy:

Answer 13

• energy of motion
  -anything that is moving can be made to do work because of its motion
  -depends of the speed and mass of an object

Question 14

for speed conversions what is the number you divide/multiply by?

Answer 14

• to convert from km/h to m/s, divide by 3.6
• to covert m/s to km/h, multiply by 3.6

Question 15

first law of thermodynamics

Answer 15

energy cannot be created or destroyed, only transformed from one for to another.

Question 16

second law of thermodynamics

Answer 16

no energy conversion is 100% efficient; some energy is always lost as heat when converting from one form to another

Question 17

energy conversion

Answer 17

energy must often be converted from one form to another to do work

Question 18

vector quantities:

Answer 18

force, velocity, acceleration, displacement, and momentum.

Question 19

vector:

Answer 19

a quantity that has both magnitude and direction

Question 20

scalar:

Answer 20

A scalar is any quantity that has magnitude but no direction

Question 21

examples of scalars

Answer 21

volume, density, speed, energy, mass, and time
distance

Question 22

what is mechanical energy?

Answer 22

the sum of gravitational and kinetic energy
Em = Ep + Ek

Question 23

in an isolated system, what happens to the mechanical energy

Answer 23

the total mechanical energy remains constant

Question 24

open system

Answer 24

matter and energy can flow in and out of the system

Question 25

closed system

Answer 25

matter can not transfer in or out of the system but energy can

Question 26

isolated system:

Answer 26

neither matter nor energy can flow in and out of the system

Question 27

steam engine:

Answer 27

thermal energy converted into kinetic energy to do work