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Physics Final Sem. 1
Units 1-12 Vocabulary, Formulas, all that jazz.
149
Physics
9th Grade
12/12/2009

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Cards

Term
Name the steps of the scientific method in order.
Definition

1. Observation

2. Question

3. Hypothesis

4. Prediction

5. Experiment

6. Explanation

Term
A scientific theory is...
Definition
a well tested explanation that may be revised as new evidence is discovered.
Term

The synthesis of several hypotheses that have been tested but never proven to be false is called a...

Definition
theory
Term

Which of the following statements about technology is NOT true?

a. answers questions

b. solves practical problems

c. seeks to create, design, build

d. puts science to use through tools

Definition
a. answers questions
Term

As an object falls freely (in the absence of air resistance) it

a. velocity increases

b. acceleration increases

c. both a and b are correct

d. none are correct

Definition
a. velocity increases
Term
A quantity divided by time is a ______.
Definition
rate
Term
Motion along a straight-line path is called _______ motion.
Definition
linear
Term
Motion is relative to the _________ of the ______.
Definition

surface

earth

Term
When we say something is in respect to, we mean it is _________ to.
Definition
relative
Term
Define speed.
Definition
A measure of how fast something is moving.
Term
Define instantaneous speed.
Definition
speed of an object at any instant
Term
Define velocity.
Definition
The speed of an object in a given direction.
Term
What is the difference between speed and velocity?
Definition
Velocity, in addition to measuring speed, measures it in a specific direction.
Term
Give the formula for speed.
Definition

Speed = distance divided by time

 

s=d/t

Term
Give the formula for acceleration.
Definition

change in velocity/ change in time

 

a=(c)v / (c)t

Term
Give the formula for final speed.
Definition
V= V+ at
Term
Give the formula for average speed.
Definition

vi + vf


2

Term
What is the force of gravity?  (answer is a number)
Definition
9.8 m/s2
Term
Give the formula for the instantaneous speed of a falling object.
Definition
v = vi + gt
Term
Give the formula for vertical distance fallen.
Definition
d = 1/2gt2
Term
Give the formula for horizontal distance traveled.
Definition
d = vt
Term
A water balloon is dropped from a second story window. What is the speed of the water balloon after 2.5 seconds? What is the average speed of the water balloon after 2.5 seconds? How far has the balloon fallen in this amount time?
Definition

speed → (19.6+29.4)


2


av. speed → vi+v


2

 

distance fallen → d= 1/2gt2

d=1/2(9.8)2.52

d=12.25

Term
non-linear motion
Definition
motion along a curved path
Term

An airplane is flying 200 km/h north. If it flies directly into a 50 km/h...

TAILWIND, what is its speed?

HEADWIND, what is its speed?

Definition

TAILWIND= 250 km/h

HEADWIND= 150 km/h

Term
A vector is a quantity that has _____ ___________ and direction.
Definition
both magnitude
Term
A scalar is a ________ that has ___________ only.
Definition

quantity

magnitude

Term
When representing velocity as a vector, the length of the vector represents the __________ of the __________.
Definition

magnitude

velocity

Term
You throw a ball straight up into the air with an initial speed of 20 m/s. What is the ball's acceleration at the highest point in its trajectory?
Definition
9.8 m/s2
Term
One Newton is equal to 1...
Definition
kg m/s2
Term

An object that has a WEIGHT of 9.8 N has a mass of:

a. 10 kg

b. 9.8 kg

c. 0.1 kg

d. 1 kg

Definition
d. 1 kg
Term
It is just as hard to push a car on the moon as it is to push the same car on earth because the _____ of the car is ______________ of _________.
Definition

mass

independent

gravity

Term

An object that has a mass of 20 kg has a weight of

a. 196 N

b. 19.6 N

c. 1.96 N

Definition
a. 196 N
Term
Give the formula for acceleration.
Definition

change in velocity

 


 

time interval

 

a=v/t

Term
What is the cause of acceleration?
Definition
Force.
Term
The combination of forces acting on an object is the ___ _____.
Definition
net force
Term
Acceleration is ________ proportional to ___ force.
Definition

directly

net

Term
If the force on an object doubles, the acceleration _______.
Definition
doubles
Term

For a given force, the acceleration produced is ______________________

________________.

Definition
inversely proportional to the mass.
Term

Define inversely proportional and give an example.

 

Definition

The two values change in opposite directions.

 

Example: If the force is 3 N, the acceleration will be 1/3 m/s2.

Term
What units do we use for force, weight and acceleration?
Definition

force= Newtons

weight= kg

acceleration= m/s2

Term
______ was the first to realize that the acceleration produced when we move something depends not only on how hard we push or pull, but also on the object's ____.
Definition

Newton

mass

Term
Give this chapter's formula for acceleration.
Definition
a=f/m
Term
Liquids and gases are called _______ because they both flow.
Definition
fluids
Term
Define air resistance.
Definition
the friction acting on something moving through air
Term
A diagram showing all the forces acting on an object is called a ________ _______.
Definition
free-body diagram
Term
Pressure is...
Definition
the amount of force per unit of area.
Term
We measure pressure in _______, which is newtons/sq.m.
Definition
pascals (Pa)
Term
When an object stops accelerating, it has reached its _________ _____.
Definition
terminal speed
Term
Define terminal velocity.
Definition
terminal speed with the direction of motion
Term
Give the formula for force.
Definition
f=ma
Term
Friction is the force due to surface ______________. It is caused by two objects rubbing _______ each other.
Definition

irregularities

against

Term
Acceleration is _______________ to force and _________ proportional to mass.
Definition

proportional

inversely

Term
There is higher resistance at higher ______.
Definition
speeds
Term
Constant velocity in presence of friction occurs when the applied _____ is equal to force of _________.
Definition

force

friction

Term
The short formula for pressure is...
Definition
p=fa
Term
The units for pressure are ________.
Definition
N/m2
Term
If action and reaction forces are ________ to the system, they cancel each other and produce no ___________ of the system.
Definition

internal

acceleration

Term
Action and reaction forces do not ______ each other when either is external to the _______ being considered.
Definition

cancel

system

Term

A wagon that is moving at a constant velocity has a net force

a. greater than the force of friction

b. equal to the force of friction

c. equal to the weight of the object

d. equal to zero

Definition
d. equal to zero
Term
As mass increases, acceleration ____________.
Definition
decreases
Term
Compared to the acceleration of the car, the acceleration of the bug after striking the windshield is...
Definition
larger.
Term
When a soccer ball is kicked, the action and reaction forces do not cancel each other out because...
Definition
they act on different objects
Term
Newton's Third Law says...
Definition
whenever one object exerts a force on another object, the object pushes back with the same force.
Term
A force of 3 N accelerates a mass of 3 kg at the rate of 1 m/s2. The acceleration of a mass of 6 kg acted upon by a force of 6 N is...
Definition
the same.
Term
A rocket is able to accelerate in the vacuum of space when it fires its engines. The force that propels the rock is the force of the _________ ______ on the ________.
Definition

exhaust gases

rocket

Term
What does momentum refer to?
Definition
inertia in motion
Term
Give the formula for momentum in words.
Definition
momentum= mass times velocity (or speed)
Term
Write the formula for momentum.
Definition

p=mv

 

where p refers to momentum, m is mass, and and v is velocity.

Term
The formula for impulse is:
Definition
Ft=mv
Term
Impulse is _______ times _____ __________.
Definition

force

time interval

Term
Impulse = change in ___________.
Definition
momentum.
Term
Impulse is _______ force times ______.
Definition

impact

time

Term
Impulse is measured in __.
Definition

Ns

(newton-seconds)

Term
Impact refers to a _____ and is measured in ________.
Definition

force

Newtons

Term
Define impact time.
Definition
The time in which momentum is brought to zero.
Term

Impulses are greater when an object...

 

(hint: BOING!)

Definition
bounces. More impulse is required for an object to bounce than to simply stop moving.
Term
The law of conservation of momentum states that...
Definition
In the absence of an external force, the momentum of a system remains unchanged.
Term
If no ___ force or net _______ acts on a system, the momentum of that system _______ change.
Definition

net

impulse

cannot

Term
When a quantity in physics (such as momentum) does not change, we say it is _________.
Definition
conserved
Term
When objects collide without being permanently deformed and without generating heat:
Definition
elastic collision.
Term
When colliding objects become tangled or coupled together.
Definition
inelastic collision.
Term
Impulse = __.
Definition

Ft

Units: N/s

Term
The formula for inelastic collisions is:
Definition
mv1+mv2=(m1+m2)Vf
Term
The formula for elastic collisions is...
Definition
mv1b+mv2b=mv1f+mv2f
Term
Work is defined as _______ times ___________.
Definition

force

distance

Term
Power = __/__
Definition

w/t

work/time

Term
What will happen to the kinetic energy of a car if its velocity doubles?
Definition
KE increases by 4x (quadruples.)
Term
Formula for kinetic energy.
Definition
KE=½m(v)2
Term
Potential energy is energy based on an objects _________ or ____________.
Definition

location

position

Term
Kinetic energy is energy based on an object's _________.
Definition
velocity
Term

Machines allow a person to use less input force when performing a task because they:

a. can change the direction of the force

b. increase magnitude of the force

c. BOTH a and b

d. NEITHER a and b

Definition
c. BOTH a and b
Term
The amount of useful work of a certain machine is 40J. What is the efficiency of the machine if the total work input was 200J? (answer is a percent)
Definition
20%
Term
The amount of PE possessed by an elevated object is equal to the _____ done to _____ the object.
Definition

work

lift

Term
Winny uses a simple lever to lift a 100N object. Winny pushes down a distance of 2m using 20 N of force. How high is the 100N object lifted off the ground?
Definition
0.4m
Term
All simple machines work ideally on the principle that work ______ equals ______ _______.
Definition

input

work output

Term
Winny can lift barrels a vertical distance of 1m or can roll them up a 2m long ramp to the same elevation. If she uses the ramp, the applied force required is...
Definition
1/2 as much.
Term
The ratio of output force to input force of a simple machine is called the ____________ ____________.
Definition

mechanical

advantage

Term
PE =
Definition

mgh

OR

Fh

Term

Efficiency =

 

Definition

AMA/TMA×100

OR

worko/work× 100

Term
AMA =
Definition
input distance/output distance
Term
Power = __/__
Definition

w/t

work/time

Term
A car traveling at 50 km/h skids 15 m. How far will the car skid if its speed doubles to 100 km/h?
Definition
60 m.
Term
What will happen to the kinetic energy of a car if its velocity doubles?
Definition
KE increases by 4x (quadruples.)
Term
Potential energy is energy based on an objects _________ or ____________.
Definition

location

position

Term
Kinetic energy is energy based on an object's _________.
Definition
velocity
Term

Machines allow a person to use less input force when performing a task because they:

a. can change the direction of the force

b. increase magnitude of the force

c. BOTH a and b

d. NEITHER a and b

Definition
c. BOTH a and b
Term
The amount of useful work of a certain machine is 40J. What is the efficiency of the machine if the total work input was 200J? (answer is a percent)
Definition
20%
Term
The amount of PE possessed by an elevated object is equal to the _____ done to _____ the object.
Definition

work

lift

Term
Winny uses a simple lever to lift a 100N object. Winny pushes down a distance of 2m using 20 N of force. How high is the 100N object lifted off the ground?
Definition
0.4m
Term
All simple machines work ideally on the principle that work ______ equals ______ _______.
Definition

input

work output

Term
Winny can lift barrels a vertical distance of 1m or can roll them up a 2m long ramp to the same elevation. If she uses the ramp, the applied force required is...
Definition
1/2 as much.
Term
The ratio of output force to input force of a simple machine is called the ____________ ____________.
Definition

mechanical

advantage

Term
PE =
Definition

mgh

OR

Fh

Term

Efficiency =

 

Definition

AMA/TMA×100

OR

worko/work× 100

Term
AMA =
Definition
input distance/output distance
Term
An ____ is the straight line around which rotation takes place.
Definition
axis
Term
What is the difference between rotation and revolution?
Definition
Rotation is on an internal axis, but revolution is on an external axis.
Term
_______ speed is distance moved per unit of time.
Definition
Linear
Term
__________ speed is the number of rotations per unit of time.
Definition

Rotational

Term
Speed of something moving along a circular path can be called ___________.
Definition
tangential
Term
Any force that causes an object to travel along a circular path is called a _______________ force.
Definition
centripetal
Term
Centripetal means...
Definition

"center-seeking"

OR

"toward the center"

Term
Centrifugal means...
Definition

"center-fleeing"

OR

"away from the center"

Term
The higher the center of gravity, the ______ the stability will be.
Definition
lower
Term
Three kinds of equilibrium:
Definition

1. Stable equilibrium

2. Unstable equilibrium

3. Neutral equilibrium

Term
Describe STABLE equilibrium.
Definition
low center of gravity, work is required to raise the CG
Term
Describe UNSTABLE equilibrium.
Definition
higher CG, any movement lowers the CG.
Term
Describe NEUTRAL equilibrium.
Definition
movement neither raises nor lowers the CG.
Term
A ball that is whirled on the end of a string moves in a circle because the _________ of the string creates an ________ force on the ball.
Definition

tension

inward

Term
If a car is traveling in a circle at a constant speed, the net force on the car is directed _______ because the car is traveling in a circle.
Definition
inward
Term
Which has a greater rotation speed: a horse nearer the outside rail of a carousel or a horse near the inside rail of a carousel?
Definition
Neither, they both have the same rotational speed.
Term

Which has a greater tangential/linear speed: a horse nearer the outside rail of a carousel or a horse near the inside rail of a carousel?

Definition
The outside horse
Term
An object wants its COG to be ______.
Definition
lower
Term
What is the centripetal force of a 2 kg tether ball that is connected to a 3 m long piece of rope and is hit with a velocity of 3 m/s?
Definition
6 N
Term

Which object will experience the greatest acceleration down an inclined plane?

a. object with large rotational inertia

b. object with small rotation inertia

c. Neither because acceleration is dependent of rotational inertia.

Definition
b. an object with a small rotational inertia
Term
Torque is defined as _____ perpendicular times _______.
Definition

force

distance

Term
Force causes acceleration; torque causes __________.
Definition
rotation
Term

Which object will experience the greatest acceleration down an inclined plane?

a. and object with a large rotational inertia

b. an object with a small rotational inertia

c. NEITHER because acceleration is independent of rotational inertia

Definition
b. an object with a small rotational inertia
Term
Angular momentum is defined as...
Definition
rotational inertia time rotational velocity
Term
An object will maintain its angular momentum unless acted upon by an unbalanced...
Definition
torque.
Term
Why did Newton think there was a force acting on the moon?
Definition
Because the moon moves in a curved path instead of a straight line.
Term
Newton reasoned that the gravitational attraction between Earth and the moon must be ____________ or ___________ by distance.
Definition
reduced or weakened
Term
Since Earth is attracted to the sun, why doesn't it fall into the sun?
Definition
Because it has sufficient tangential velocity.
Term
If the mass of the earth increased, with no change in the radial distance, your weight would...
Definition
increase also.
Term
If the radius of earth decreased, with no change in mass, your weight would _________.
Definition
increase
Term
The moon and earth move toward each other under mutual gravitation: which has the greater force?
Definition
They are the SAME!
Term
Suppose the gravitational force between two massive spheres is 100 N. If the distance between the spheres is doubled, what is the force between the masses?
Definition
25 N.
Term
By noticing the perturbations of known planets, astronomers using the law of gravitation were able to discover the __________ of other planets and _____, such as Pluto and Uranus' ______.
Definition

presence

moons

moons

Term
Equation for Torque.
Definition
T= Fperpendicular × d
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