1
Q
What is Motion
A
a change in an objects position relative to and objects reference point
- An objects motion will change if the reference point changes
- An objects distance is different than its displacement
2
Q
What is Distance and Displacement
A
Distance is the total length an object travels. Displacement is the difference between an objects starting point and an objects ending point .
The SI unit for distance is meters.
3
Q
What is speed?
A
It is the distance an object travels over time. Speed = Distance/Time
4
Q
What are three ways to talk about speed?
A
- Constant speed – traveling the same distance per second
- Average speed – the total distance an object travels in a period of time
- Instantaneous speed – an objects speed at a specific moment in time
5
Q
What is the Distance Time Graph?
A
It is what we use to graph Motion. On the Distance Time Graph the x-axis is the time and the y-axis is the distance. The steeper the line the higher the speed.
6
Q
What is velocity?
A
It is the speed of an object and the direction of its motion? Velocity= Distance/Time. Velocity Must include a Direction. Velocity changes whenever its speed or direction changes.
7
Q
What is Momentum?
A
It is the product of the objects mass and its velocity. The greater the mass or velocity of an object the greater the momentum. Kilograms/ meters per second is used to represent momentum.
8
Q
What is Force?
A
It is a Push or pull on an object
9
Q
what is Net Force?
A
It is the sum of all the forces acting on an object
10
Q
Balance Force?
A
It is when the net force of an object is = 0
11
Q
Unbalanced Force?
A
When the Net Force of an Object is not = 0
12
Q
What is Friction?
A
The force that opposes the sliding motion of 2 surfaces that are touching each other
13
Q
The amount of friction between two objects depends on?
A
- The size of the bumps – the larger the bumps the more friction
- The amount of force applied to the surface – the greater the force applied the more friction
14
Q
What are the types of friction and what are they?
A
- Static Friction – friction between 2 surfaces where the object isn’t moving
- Sliding Kinetic Friction – friction between 2 surfaces where 1 object is sliding past another
- Rolling Kinetic Friction – similar to sliding but there is much less contact because there are wheels
15
Q
What is gravity?
A
an attracted force between 2 objects
Any objects with mass have a gravitational force
16
Q
What Affects gravitation force?
A
- Distance – the closer you are the more gravitational force
- Mass – the bigger the mass the more gravitational force
17
Q
What is a Gravitational Field?
A
a region of space that has a physical quantity at each point.
18
Q
What is weight?
A
the gravitational force exerted on an object.
19
Q
Newtons First Law of Motion?
A
An object at rest remains at res and an object that is in motion stays in motion until acted on by an unbalanced force
20
Q
What is Inertia?
A
It is the Tendency of objects to resist motion.
21
Q
Newtons Second Law of Motion
A
The acceleration of an object depends on the mass of the object and the amount of force that is applied to the object
22
Q
Newtons 3rd Law of Motion?
A
When an object exerts a force on a second object the second object exerts an equal and opposite force on the first
23
Q
What is Terminal Velocity?
A
the maximum speed an object will reach when falling through a substance
24
Q
What is Free Fall?
A
Occurs when gravity is the only force acting on an object
Only happens when there is no resistance
25
What is Centripetal Force?
a force going towards the middle of a object moving in a circular motion
26
what is Law of conservation of momentum?
if no external forces act on a group of objects in motion the momentum will not be lost
27
What is Temperature ?
measure of average kinetic energy of particles that make up a substance
28
What is Thermal Energy?
the combination of the kinetic and potential energy of the particles of a substance
29
What is Heat?
It is the transfer of thermal energy>
30
What is specific heat?
the amount of energy needed to raise the temp of 1 kg by 1 degree Celsius
31
What are three ways thermal energy can be transferred?
1. Conduction – transfer of thermal energy by collisions of particles that make up matter
- Must be direct contact between objects for conduction to take place
- Transfers thermal energy without transferring matter
2. Convection – transfer of thermal energy in a fluid by movements of warmer and cooler fluid
- Fluid = liquid or gas
- When convection occurs particles that are warmer move from one place to another
- Boiling water (water circulates as it increases and decreases temp)
3. Radiation – transfer of thermal energy through electromagnetic waves
- Light energy bounces off on an object and some of the light energy is converted to thermal energy
- Can travel through a vacuum (space)
32
What are the 4 heating systems?
1. Forced air heating system
Furnace: burns some type of fuel
Heats air through the furnace a fan blows the air through ducts and into all the rooms in a building – each room has a separate vent where cold air is returned to the furnace
2. Radiator heating system
Fuel that burns heats water
Steam travels through ducts to radiators located in each room
3. Electric heating system
Each room has its own electric heater – more expensive
Work the same way as a space heater
Electricity warms coils which produces heat
4. Solar heating
Uses energy directly from the sun to heat a building
33
What is Passive and Active Solar energy?
Passive solar energy: getting thermal energy directly from the sun
- Opening shades, blinds and letting the sun in
Active solar energy: having solar panels collect sunlight and turn it into thermal energy
34
What is thermodynamics?
the study of the relationship between thermal energy and work
35
What are the laws of thermodynamics ?
1st LAW: if the mechanical energy of a system is constant than the increase in thermal energy of a system = the sum of thermal energy transferred in and work done on that system
2nd LAW: energy spontaneously spreads from regions of higher concentration to regions of lower concentration
Energy is always transferred from warmer objects to cooler objects
36
What are Heat Engines?
Thermal energy can be converted to mechanical energy – used to move objects
Heat engine: a device that converts thermal energy into mechanical energy
Fuel is burned producing gas or steam that powers pistons allowing the object to move
37
What are the 2 types of heat engines?
1. Internal combustion – fuel burned inside a set of cylinders
Cars – trucks – more efficient – 25%
2. External combustion - fuel burned outside the cylinders
Steam powered trains
38
Transferring thermal Energy?
Contain a coolant kept at a temp lower than the temp inside the fridge. Electricity allows the coolant to stay cold
Coolant is moved through coils throughout fridge – thermal energy is absorbed by the coolant as it travels through the coils
Air conditioner works the same way except an air conditioner the coolant stays in one place it doesn’t move throughout the air conditioner.
39
What is matter Composed of?
It is composed of atoms?
40
Atoms are made up of?
- Protons – positive charge
- Neutrons – no charge
- Electrons – negative charge
41
What is static electricity?
accumulation of excess electric charges on an object
42
What is conservation of charge?
charges can be transferred from object to object, but they can’t be destroyed
43
2 things that affect electric force on objects?
1. Number of charges
As the number of charges increases the electric force increases
2. Distance between objects
As distance increases electric force decreases
44
What is an electric field?
an area around an electric charge that exerts a force and causes other forces to be attached or repelled
45
what is a conducter?
a material through which electrons move easily – metal - water
46
What is an insulator?
a material through which electrons move slowly – plastic – rubber
47
Ways charges can be transferred
1. Charge by contact
Objects touching or rubbing against each other
2. Charge by induction
Rearrangement of electrons on an object caused by a nearby object
Objects aren’t touching
48
What is electric discharge?
the transfer of charges between two object because of a buildup of static electricity
49
What is an electroscope?
a device that can detect electric charges
50
What is electric current?
the net movement of electric charges in a single direction the net movement of electric charges in a single direction
51
What is voltage Difference?
the force that causes electric charges to flow
Measured in Volts (V)
52
What is electric circuit?
a closed path that electric current flows
53
What are the three parts to an electric circuit?
1. Energy source – Battery
2. Wires – what transports energy
3. Load – thing using energy
54
What are Batteries?
Create and maintain a voltage difference so current can continue to flow
55
What are the three parts to a battery?
1. 2 electrodes
2. 1 cathode (positive flow)
3. 1 anode (negative charge)
56
What are the two types of batteries?
Dry cell battery and wet cell battery
57
What is Resistance?
the tendency of an object to resist the flow of electrons and convert electrical energy to other forms
Most common form of resistance is thermal energy
Resistance is measured in ohms
58
what are the two types of currents?
1. Alternating electric current – direction of the charge’s changes
120 V means direction changes 120 times per second
2. Direct current – direction of the charges is always the same
Most things that run on a battery run on direct current
Most electric devices don’t have simple circuits
Most have multiple energy sources wire paths and loads
59
What are the two types of circuits?
1. Series circuits – circuit with one branch for current to flow
Everything on the circuit is either on or off
2. Parallel circuits – circuits with multiple branches for current to flow
More common – one branch can be on while others are off or vice versa
Households are made up of many parallel circuits
All of the circuits are connected to a circuit breaker
Circuit breaker: a device used to keep circuits from getting too hot, so they don’t start on fire
If the circuit breaker didn’t work wires will get to hot and they will start insulation on fire
Besides a breaker fuses are used for safety
Fuse: a small piece of metal in a glass container
If the current gets too high the wire melts and the circuit is open
60
What is electric Power?
the rate at which electric energy is converted to another form of energy
Measured in watts
61
What are fossil Fuels?
fuel that was formed from the remains of antient plants and animals buried and altered over a million years ago
62
three types of petroleum?
1. Petroleum
- flammable liquid formed from the decay of ancient organisms
- most commonly used fossil fuel aka crude oil
- Not as useful in its form will need to fractional distillation it
- Some components include – gas lubricants – lamp oil – etc.
2. Natural gas
- Composed mostly of methane but also contains other gasses
- The gasses are smaller and lighter than compounds found in petroleum
- The use of natural gas is increasing because it is cleaner than other fossil fuels
- Contains the most amount of stored energy
3. Coal
- Solid fossil fuel found in mines
- In the early to mid-1900s coal was the dominant source of fuel because it was easy to get and use
- Modern machines aren’t built to use coal
- It is the dirtiest fossil fuel – supply is running out – other fuels are cheaper
63
What is Population?
all of the individuals of one species living in one area
In 1810 the population was 1 billion
It took 100 years for the population to reach 2 billion
It was only 50 more years that we reached 3 billion
Our population has grown rapidly and today we are at 7.8 billion people
64
What is carying Capacity?
the largest number of individuals an environment can support over a long period of time
65
What is a wave?
a repeating disturbance that transfers energy through matter of space
66
What is a mechanical wave?
a wave that can only travel through matter
- Needs a medium whether it is solid liquid or gas
- Sound seismic and water waves all example
67
What is a Medium?
the matter a wave travels through
68
What are electromagnetic waves?
waves that don’t need matter to travel through a vacuum
Science Semesters Chapter 2-9
flashcards
Decks in class (1)
# Cards
