98 terms

# West General Physics Review

All physics concepts.
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In science, a theory is
a synthesis of a large body of well-tested knowledge
The scientific method is most effective in
gaining, organizing, and applying new knowledge
In science, an educated guess is a
hypothesis
What is an area of physics that studies motion and its causes?
mechanics
A baker makes a loaf of bread. Which area of physics does this involve?
thermodynamics
According to the scientific method, how does a physicist formulate and objectively test hypotheses?
by experiments
In the steps of the scientific method, what is the next step after formulating and objectively testing hypotheses?
interpreting results
A hiker uses a compass to navigate through the woods. Which area of physics does this involves?
electromagnetism
What two dimensions, in addition to mass, are commonly used by physicists to derive additional measurements?
length and time
The SI base unit used to measure mass is the
kilogram
The SI base unit for time is
1 second
How does a scientist reduce the frequency of human error and minimize a lack of accuracy?
take repeated measurements
use the same method of measurement
control
Three values were obtained for the mass of a metal bar: 8.83 g; 8.84 g; 8.82 g. The known mass is 10.68. The values are
precise
Calculate the following, and express the answer in scientific notation with the correct number of significant figures: 21.4+15+17.17+4.003
5.8 x 10^1
Calculate the following, and express the answer with the correct number of significant figures: 1.23 x 0.89
1.1
What is not a step that is part of the scientific method?
Repeat the experiments until the answers match the predictions (doesn't have to match your predictions)
A hypothesis
an educated guess that has yet to be proved by experiment
A theory is
a synthesis of a large collection of information including well-tested guesses
One difference between a hypothesis and a theory is that a hypothesis
is a guess that has not been well tested, whereas a theory is a synthesis of well-tested guesses
What is an example of a scientific hypothesis?
Atoms are the smallest particles of matter that exist (If it is a valid hypothesis, there must be a test for proving that it is wrong)
To test a scientific hypothesis you would
set up many experiments and look at the results
How many sig figs does the number 0.006080?
four
A human hair is approximately 50 micrometers in diameter. Express this is meters.
5.0 x 10^-5 m
When a hypothesis has been tested over and over again and has not been contradicted, it may become a
law
physics is the most basic science because
it is about the nature of basic things like forces, energy, and motion
Listening to the radio involves what area of physics?
vibrations and wave phenomena
The SI basic unit for temperature is
Kelvin
What is 0.000000452 written in scientific notation?
4.52 x 10^-7 m
The law of inertia states that an object
maintains its motion
The law of inertia applies to
both moving and nonmoving objects
A sheet of paper can be withdrawn from under a container of milk without toppling it if the paper is jerked quickly. The reason this can be done is that
the milk carton has inertia
Compared to its weight on Earth, a 10-kg object on the moon will weigh
less
What is the tendency of an object to maintain its state of motion
inertia
The magnitude of the gravitational force acting on an object is
weight
A measure of the quantity of matter is
mass
According to Newton's law of inertia, a railroad in motion should continue going forever even if its engine is turned off. We never observe this because railroad trains
always have forces that oppose their motion
How many sig figs does the number 500,000 have?
one
Convert 5.52x10^8 g into kg using scientific notation.
5.52x10^5 kg
How does acceleration of an object change in relation to the applied force? It is
directly proportional
If the force acting on a cart doubles, what happens to the cart's acceleration?
It doubles
Suppose a cart is being moved by a force. If suddenly a load is dumped into the cart so that the cart's mass doubles, what happens to the cart's acceleration?
It halves
How much force is needed to accelerate a 4.0 kg physics book to an acceleration of 2.0 m/s^2?
8.0 N
If shopping cart A has five times more mass in it than shopping cart B and the two cars are pushed with equal forces, you can expect the acceleration of shopping cart A to be
1/5 times that of shopping cart B
A bag of groceries has a mass of 11 kg. What is the bag's weight?
108 N
What is the cause of acceleration?
force
A newton is equivalent to which quantities?
kg x m/s^2
A net force of 6.8 N accelerates a 31 kg scooter across a level parking lot. What is the magnitude of the scooter's acceleration?
0.22 m/s^2
What is the speed of an object at rest?
0.0 m/s
Suppose you take a trip that covers 180km and takes 3 hours to make. Your average speed is
60 km/h
x/t
speed
180km/3h=
60km/h
Acceleration is defined as
the rate of change of velocity
A car accelerates at 2 m/s^2. Assuming the car starts from rest, how much time does it need to accelerate to a speed of 20m/s?
10 seconds
The motion of a ball on an inclined plane is described by the equation: change in x=1/2a(change in time)^2. Which of the following must have a value of zero?
initial velocity (vi)
Suppose an object is in free fall. Each second the object falls
a larger distance than in the second before
Objects that are falling toward Earth in free fall move
faster and faster
Would a leaf or a stone fall with greater acceleration in a vacuum?
they would accelerate at the same rate
A baseball catcher throws a ball vertically upward and catches it in the same spot as it returns to the mitt. At what point in the ball's path does it experience zero velocity and nonzero acceleration at the same time?
at the top of its path
At the instant a ball is thrown horizontally with a large force, an identical ball is dropped from the same height. Which ball hits the ground first?
Neither. They both hit the ground at the same time.
Identify the following quantities as scalar or vector: the mass of an object, the number of leaves on a tree, wind velocity.
scalar, scalar, vector
What physical quantity has both magnitude and direction?
vector
A ball thrown in the air will never go as far as physics ideally would predict because
air friction slows the ball
What is a physical quantity that has magnitude but no direction?
scalar
At what part of a path does a projectile have minimum speed?
At the top of its path
In the absence of air resistance, the angle at which a thrown ball will go the farthest is
45 degrees
What is the resultant of a 3-unit vector and a 4-unit vector at right angles to each other?
5 units
Which of the following is a vector quantity: velocity, temperature, volume, mass?
velocity
A projectile is fired horizontally in a vacuum. The projectile maintains its horizontal component of speed because it
is not acted on by any horizontal forces
A person is attracted towards the center of Earth by 440-N gravitational force. The force with which Earth is attracted toward the person is
440 N
Suppose the force of friction on a sliding object is 25 N. The force needed to maintain a constant velocity is
25 N
What is the path of a parabola (in the absence of friction)?
a parabola
In a coordinate system, the magnitude of the x component of a vector and theta, the angle between the vector and x-axis, are known. The magnitude of the vector equals the x component
divided by the cosine of theta
What is the name of the type of friction that opposes the movement of two surfaces that are in contact and are sliding over each other?
kinetic friction
Two objects move toward each other b/c of gravitational attraction. As the objects get closer and closer, the force b/w them
increases
Suppose the gravitational force b/w two massive spheres is 100N. If the distance b/w the spheres is doubled, what is the force b/w the masses?
25 N
Suppose the gravitational force b/w two spheres is 30N. If the magnitude of each mass doubles, what is the force b/w the masses?
120 N
The gravitational force b/w two masses is 36 N. What is the gravitational force if the distance b/w them is tripled?
4.0 N
mass
amount of matter in an object
matter
that which has mass and occupies space
energy
the ability to do work or cause a change
kinetic energy
energy of motion
potential energy
energy of position, stored energy
mechanical energy
the energy that moves objects
sound energy
energy of vibrations carried by air, water, or other matter
chemical energy
energy that is stored in the chemical composition of matter
thermal energy
heat energy; the total amount of energy from the movement of particles in matter
electromagnetic energy
A form of energy that travels through space as waves.; includes light waves, infrared waves, radiowaves, ultraviolet waves, and X-rays
nuclear energy
the energy released by a nuclear reaction, energy stored in the nucleus of every atom may be released by a fission reaction or by a fusion reaction
law of conservation of energy
energy cannot be created or destroyed but can be changed from one form to another
energy efficiency
a measurement of usable energy after an energy conversion
6 forms of energy
mechanical, sound, thermal, chemical, electromagnetic, nuclear
3 types of potential energy:
gravitational, chemical, elastic
2 factors that determine gravitational potential energy:
the object's mass and height above ground
2 factors that determine an object's kinetic energy:
the object's mass and velocity (speed)
example of elastic potential energy:
rubber band stretched out or a slinky stretched out
example of chemical potential energy:
battery
apple waiting to be eaten
Potential Energy