Week 1 & 2 Basics of Physics

Question 1

What is Newton’s first law of motion?

Answer 1

An object at rest remains at rest until a force acts upon it.

Aka: law of inertia

Question 2

What is velocity?

Answer 2

• describes how the position of an object changes with time.
• its a vector.
• also has to do with position of origin. If end point same as starting point, velocity is zero

-generally m/s

Question 3

What are vectors?

Answer 3

• have both magnitude and direction
• vectors can be added to give the resultant vector.
• mass is not a vector

Question 4

What is acceleration?

Answer 4

• describes how velocity changes with time
• a vector quantity
• generally m/s2

Question 5

What is force?

Answer 5

• a push or pull

- related to Newton’s second law: F=ma

Question 6

What is gravity?

Answer 6

• it is the universal attraction between all objects.
• Newton’s third law: for every action there is an equal and opposite reaction
• 9.8m/s2

Question 7

What is weight?

Answer 7

• Weight is the gravitational force exerted on an object by another larger object such as the earth
• W=mg

Question 8

What is pressure?

Answer 8

-pressure is force per unit area.

Pressure = force/area

• unit is pounds per square inch (psi)
• pressure increases by either increasing the applied force, or decreasing the area the force is applied
• pressure decreases by either decreasing the applied force, or increasing the area the force is applied

Question 9

What is atmospheric pressure?

Answer 9

Air pressure results from gravity pulling on the atmospheric, and the resulting force is spread over the earth’s surface

• the weight of the air above us
• roughly 14 psi = 1 atmosphere = 760mmHg

Question 10

What is a barometer?

Answer 10

Measures absolute pressure or atmospheric pressure.

-

Question 11

What is a Bourdon gauge?

Answer 11

• measure gauge pressure, but is affected by changes in atmospheric pressure.
• use on gas cylinders
• measures the differences between the pressure in the tank an atmospheric pressure.
• Ptotal = Pgauge + Patmosphere

-even if gauge reads zero, still pressure in the tank

Question 12

What are scalar quantities?

Answer 12

• they have magnitude only.
• They can be additive

Distance, height, weight, speed

Question 13

What is an aneroid bellow?

Answer 13

• doesn’t need liquid.

- relies on expansion and contraction of a bellow as pressure changes

Question 14

What is barometric pressure?

Answer 14

-The measure of atmospheric pressure

Question 15

What is work?

Answer 15

The expenditure of energy

Measured in joules

W = F x d

F: force
D: distance

Can also be W = P x change of volume
P: pressure

Question 16

What is power?

Answer 16

• the rate of doing work, or the amount of energy transferred per unit of time
• measured in watts

Question 17

What is a machine?

Answer 17

• device for multiplying force
• does not supply energy, but provides an advantage
  
  • mechanical advantage = force output/force input

Question 18

What is energy?

Answer 18

Capacity for doing work

Question 19

What are 2 types of engery?

Answer 19

Kinetic energy

Potential energy

Question 20

What is kinetic energy?

Answer 20

Energy that a body possesses by being in motion

Question 21

What is potential energy?

Answer 21

Energy possessed by an object by virtue of its position relative to other objects

Question 22

What is the law of conservation of energy?

Answer 22

Energy can not be created or destroyed

-it can be changed from one form to another

Question 23

What is the SI standard unit of energy?

Answer 23

Joules

Question 24

What is internal energy?

Answer 24

The sum of kinetic and potential energies of a system

Question 25

What is thermodynamics?

Answer 25

Branch of physics concerned with heat and temperature and their reaction to energy

Question 26

What is the Zeroth Law of Thermodynamics?

Answer 26

-2 objects A/B are same temperature. B/C are same temperature. Therefore A/C are equal temperature (thermal equilibrium) and no heat will flow between A/C

Question 27

What is the First Law of Thermodynamics?

Answer 27

- heat is a form of energy, and thermodynamics states that heat is a form of energy. Therefore, thermodynamic processes are subject to the principle of conservation of energy. * Heat can not be created or destroyed - from slide: a change in the internal energy of a system is equal to the sum of the heat flow of a system and the work done by/on the system

Question 28

What does exothermic mean?

Answer 28

Gives off heat

Question 29

What does endothermic mean?

Answer 29

Absorption of heat

Question 30

What is the Second Law of Thermodynamics?

Answer 30

Heat spontaneously flows from a hot body to a cold body when 2 bodies are brought into thermal contact -AKA: entropy law *important for keeping pt warm in OR*

Question 31

What does entropy mean?

Answer 31

A measure of randomness or disorder in a system. Systems can be randomized, chaotic, or evenly mixed. A system will never become more organized

Question 32

What is Third Law of Thermodynamics?

Answer 32

It is not possible to lower the temperature of an object to absolute zero

Question 33

What is the difference between heat vs. temperature?

Answer 33

- Heat is a process, not a product - heat is energy which can be transferred - temperature is a numerical ranking of “hot” or “cold” - temperature is an arbitrary number - temperature is a measurement of the tendency to gain or loose heat

Question 34

What is thermal expansion?

Answer 34

-the tendency of matter to change in shape, area, and volume in response to a change in temperature. - an increase in heat will cause an object to expand - expansion is constant for a given material - expansion is constant in all directions

Question 35

What is the unit of measurement for heat?

Answer 35

Calorie Calorie is the heat required to raise 1g of water 1 degree C

Question 36

What is specific heat?

Answer 36

The amount of heat needed to raise the temperature of 1 gram of material by 1 degree C - materials with a high specific heat make good insulators - materials with a low specific heat make good thermoconductors

Question 37

What is heat capacity?

Answer 37

Heat required to raise the temperature of a given material Heat capacity = mass x specific heat

Question 38

What factors affect the rate of change of heat of an object?

Answer 38

- heat capacity (inv proportional) - temperature gradient (dir proportional) - surface area (dir proportional) - forced convection (dir proportional)

Question 39

What are the different types of heat transfer?

Answer 39

*how heat is lost* - radiation: 40% - convection: 30% - conduction: 20% - evaporation: 10%

Question 40

What is convection?

Answer 40

Heat transfer caused by a liquid or gas

Question 41

What is conduction?

Answer 41

Transfer of heat by the direct interaction of molecules in a hot area with molecules in a cooler area

Question 42

What is radiation?

Answer 42

Energy emitted from an object Requires no physical medium or physical contact between the objects

Question 43

What is evaporation?

Answer 43

Heat loss primarily through respiration

Question 44

What are the 4 fundamental forces?

Answer 44

- Strong nuclear force - Electromagnetic force - Weak nuclear force - Gravitational force