Unit B - Physics

Question 1

How would you determine the average speed of a given object?

Answer 1

Average speed = distance travelled/time elapsed

V = d (final) - d (initial)/t (final) - t(initial)

Question 2

What is the difference between a scalar quantity and a vector quantity?

Answer 2

A scalar quantity only indicates the magnitude of the quantity, whereas a vector quantity indicates both magnitude and direction.

Question 3

Describe uniform motion

Answer 3

Uniform motion is a term used to describe an object that is traveling at a constant rate of motion in a straight line.

Question 4

Describe the X axis method of plotting a graph

Answer 4

• up and right are positive

* down and left are negative

Question 5

Describe the navigator method of plotting a graph

Answer 5

• North and east are positive

* South and west are negative

Question 6

What is the formula for average velocity?

Answer 6

Average velocity = displacement/time elapsed

Question 7

Difference between distance and displacement

Answer 7

Distance is a scalar quantity whereas displacement is a vector quantity.

Question 8

List two ways that positive acceleration can occur

Answer 8

Positive acceleration can occur when the change in both the magnitude of the velocity and the direction are positive or when the change in both the magnitude of the velocity and the direction are negative.

Question 9

List two ways that negative acceleration can occur

Answer 9

Negative acceleration occurs when the change in the magnitude of the velocity is negative while the direction is positive or when the change in the magnitude of the velocity is positive and the direction is negative.

Question 10

What is the formula for analyzing accelerated motion?

Answer 10

Acceleration = change in velocity/time interval

v(f) - v(i)/t(f) - t(i)

Question 11

What is force?

Answer 11

Force is defined as a push or a pull on an object, it is measured in newtons.

Question 12

What happens when an unbalanced force is applied to an object?

Answer 12

When an unbalanced force is applied to an object, the object will gain or lose energy which in turn leads to a change in motion.

Question 13

Define “work” in a physics context

Answer 13

Whenever a force moves an object through a distance that is in the direction of the force, work is done on the object.

Question 14

What is the formula to find the amount of work done on an object?

Answer 14

Work = force x distance
W = Fd
Measured in joules (J)

Question 15

Three conditions for work to be done on an object.

Answer 15

• there must be movement
• there must be a force
• The force and the distance the object travels must be in the same direction

Question 16

Define chemical energy

Answer 16

Chemical energy is the potential energy stored in the chemical bonds of compounds.

Question 17

Define electrical energy

Answer 17

Electrical energy is the work done by moving charges.

Question 18

Define nuclear energy

Answer 18

Nuclear energy is the potential energy stored in the nucleus of an atom.

Question 19

Define solar energy

Answer 19

Solar energy is energy from the sun. This energy travels to Earth as electromagnetic radiation.

Question 20

Define kinetic energy

Answer 20

Kinetic energy is flowing water, wind, or any object in motion that could be made to do work because of its motion.

Question 21

Define gravitational potential energy

Answer 21

Gravitational potential energy is the potential for an object to do work because of its position above the Earth’s surface.

Question 22

Define mechanical energy

Answer 22

Mechanical energy is the sum of kinetic energy and gravitational potential energy

Question 23

Gravitational potential energy equation

Answer 23

Ep(grav) = mgh
Or
Ep(grav) = Fd

Question 24

Define elastic potential energy

Answer 24

Elastic potential energy is energy in which force can be applied against an opposing force resulting in a change in potential energy.

Question 25

Kinetic energy formula

Answer 25

Kinetic energy = 1/2 (mass) (speed)^2 | Ek = 1/2mv^2

Question 26

Mechanical energy formula

Answer 26

Mechanical energy = kinetic energy + potential energy

Question 27

Law of conservation of energy

Answer 27

The law of conservation of energy states that the total amount of energy in a given situation remains constant. Energy can be converted from one form to another but the total amount of energy never changes.

Question 28

Evidence of energy conversions

Answer 28

* motion * change in position * change in shape * change in temperature

Question 29

Define an open system

Answer 29

Exchanges both matter and energy with its surroundings

Question 30

Define a closed system

Answer 30

Cannot exchange matter but can exchange energy with its surroundings.

Question 31

Define an isolated system

Answer 31

Cannot exchange either matter or energy with its surroundings

Question 32

First Law of Thermodynamics

Answer 32

Total energy, including heat, in a system and its surroundings remains constant.

Question 33

Second Law of Thermodynamics

Answer 33

Heat flows naturally from a hot object to a cold object, but never naturally from a cold object to a hot object.

Question 34

Heat engine vs. Heat pump

Answer 34

Heat engine follows law of thermodynamics, motion of heat going from hot to cold is harnessed as kinetic energy. Heat pump requires energy to move heat from a cold area to a hot area.

Question 35

Gunpowder engine

Answer 35

* Successful reciprocating pump needed force to drive piston forward and force to pull it back * Gases generated by an explosion inside the engine drove a piston forward into a cylinder. * Engine never developed due to safety hazards and no mechanism to pull the piston back

Question 36

The heat engine

Answer 36

* The heat engine used heat to create steam to do work | * The heat engine was never created because they could not make the large drum in which the water was to be heated

Question 37

The Savery engine

Answer 37

* first successful steam powered pump used to pump water out of mines * could lift water to a height of only 6 m

Question 38

The Newcomen engine

Answer 38

* A boiler produced steam that forced a piston up a cylinder. When cold water was sprayed on outside of cylinder, steam would condense and piston would move back down cylinder. * cycle of heating and cooling the cylinder was inefficient and engine required tremendous amounts of heat to function.

Question 39

The Watt engine

Answer 39

* Engine run on steam where boiler cylinder always remained hot and had a separate condenser to cool steam. Three times more effective than Newcomen engine * steam engines were very large, therefore they could not replace horse-drawn carriages

Question 40

The internal combustion engine

Answer 40

• petroleum fueled internal combustion engine used gasoline instead of coal gas, like other internal combustion engines. This engine was small enough to power road vehicles.

Question 41

What is the formula for efficiency?

Answer 41

Efficiency = useful work output/useful work input

Question 42

Formula for percent efficiency of mechanical energy

Answer 42

Percent efficiency = useful mechanical energy (work output)/total mechanical energy (work input) x 100%

Question 43

Formula for the percent efficiency of thermal energy

Answer 43

Percent efficiency = heat (useful output)/heat (total input) x 100%

Question 44

Name five solar energy sources

Answer 44

Solar radiation, wind energy, water energy, biomass, fossil fuels.

Question 45

Name three non-solar energy sources

Answer 45

Geothermal energy, nuclear energy, and tidal energy.

Question 46

What is the difference between a renewable energy source and a non-renewable energy source?

Answer 46

A renewable energy source is one that is continually and infinitely available, whereas a non-renewable energy source is limited and irreplaceable

Question 47

Define cogeneration

Answer 47

Cogeneration is the process of using waste energy from one process to power a second process.

Question 48

Define sustainable development

Answer 48

Sustainable development is economic development that meets current needs without compromising the ability of future generations to meet their needs.