Physics - Semester 1 Exam

Scientific Notation

used when a number is really big or small

* positive power of 10: moves decimal point to the right
* negative power of 10: moves decimal point to the left
* ex. 6.02 \* 10^2

Decimal Notation

used when number is written with all zeros

* ex. 43,500

Volume

amount of space occupied by an object

Kilometer

used to measure distance

Liter

used to measure volume

Celcius

used to measure temperature

Grams (g)

used to measure mass

Milliliter (ml)

used to measure volume

Millimeter (mm)

smallest unit

g/ml

used to measure density

D=m/v

density = mass/volume

V=m/d

volume = mass/density

Quantity of matter

mass

Hypothesis

testable prediction

Independent Variable

factor in all experiments that is changed by the experimenter

Dependent Variable

can be caused when there is a change in independent variable

Experiment

test of a hypothesis

Theory

observations supported by experimental results

Graph

visual display of information or data

X-axis

independent variable

Y-axis

dependent variable

Mass

amount of matter in an object

Volume

amount of space and object occupies

Distance

how far an object has moved

Displacement

distance and direction of an object’s change in position from the orgin

Instantaneous Speed

speed at a given point in time

Velocity

rate of change of an object’s position

Acceleration

rate of change of an objects velocity

P=m\*v

momentum = mass\*velocity

D=s\*t

distance = speed\*time

S=d/t

speed = distance/time

T=d/s

time = distance/speed

Unit for speed

m/s

Unit for acceleration

m/s^2

Field

region of space that has physical gravity at every point

Force

push or pull

Friction

force that opposed the sliding motion of two surfaces that are touching each other

Gravity

an attractive force between any two objects that depends on the mass of the objects and the distance between them

Net force

when two or more forces act on an object at the same time, the forces combine

Weight

gravitational force exerted on an object

Balanced force

object stays in the same place

Acceleration due to gravity on earth

9\.8 m/s^2

Newton (N)

unit for force and weight

Kilogram (kg)

unit for mass

W=m\*g

weight = mass\*gravity

G=w/m

gravity = weight/mass

M=w/g

mass = weight/gravity

Inertia

tendency of an object to resist any change in motion

Newtons first law of motion

an object moving at a constant velocity keeps moving at that velocity until acted on by an unbalanced force

Newtons second law of motion

an objects acceleration is in the same direction as the net force and is equal to the net force divided by the mass

Newtons third law of motion

when an object exerts a force on a second object, the second object exerts an equal but opposite force on the first

Centripetal Force

a force exerted toward the center of a curved path

Terminal Velocity

maximum velocity an object will reach while falling through air

Free fall

when gravity is the one force action on an object

Air resistance

a friction-like force apposing objects moving in air

Law of conservation of momentum

if a group of objects exerts force only on each other, their total momentum does not change

F=m\*a

force = mass\*acceleration

A=f/m

acceleration = force/mass

M=f/a

mass = force/acceleration

A = Fv - Vi/t

acceleration = velocity final - velocity initial/time

Scientific method

organized set of investigation procedures


1. state the problem
2. gather information
3. form a hypothesis
4. test the hypothesis
5. analyze data
6. draw conclusions

Constants

a factor that does not change when other variables change

Control

standard by which the test results can be compared

Model

Represents an idea, event, or object to help people better understand it

Scientific theory

explanation of things or events based on knowledge gained from many observations and investigations

Scientific law

statement about what happens in nature and that seems to be true all the time

* theory can be used to explain laws but theories do not become laws

SI units

universally accepted and understood by scientists throughout the world

Reference point

needed to determine the position of an object

Displacement

the distance and direction of an objects position relative to the starting point

Speed

the distance an object travels per unit of time

Constant speed

if something stays at one speed

Average speed

total distance traveled divided by the total time of travel

Instantaneous speed

speed at one point in time

Distance - time graph

plots data for distance and time

Net force

when two or more forces act on an object at the same time, the forces combine

Friction

force that opposes the sliding motion of two surfaces that are touching each other

Friction is caused by

microwelds that form where the surfaces are in contact

Static friction

force that keeps two surfaces at rest from sliding across each other

Sliding friction

force that works against the motion of two surfaces that are sliding across each other

Rolling friction

frictional force between a rolling object and the surface it rolls on

Law of Universal Gravitational

lets us find force of gravity between two objects if their masses and distance is known

Field

a region of space that has physical quantity (such as force) at every point

Inertia

the tendency of an object to resist any change in its motion

Air Resistance

force that opposes the movement of objects through the air

Terminal velocity

highest speed a falling object can reach

Centripetal acceleration

acceleration toward the center of a curved path

Centripetal force

the net force exerted toward the center of a curved path

Momentum

an object is the product of its mass and velocity

Work

energy transferred when a force makes an object move a certain distance

Machine

a device that changes the force or increases the motion from work

Simple Machine

does work with just one movement of the machine

* ex. knife

Compound Machine

combination of two of more simple machines

* bicycle

Efficiency

a measure of how much of the work put into a machine, the input work, is changed into useful work by the machine

Mechanical advantage

the ratio of the output force to the input source

Energy

the ability to cause change

Systems

anything you can draw a boundary around

Kinetic energy

energy a moving object has because of its motion

Potential energy

stored energy due to its position

Gravitational potential energy (GPE)

energy that is stored by its object that are above Earth’s surface

Density

the quantity of something per unit volume, unit area, or unit length