Physics Chapter 3 Force and Motion & Chapter 4 Work and Energy
Which of the following objects has the greatest kinetic energy? a. an object with a mass of 4m and a velocity of v. b. an object with a mass of 3m and a velocity of 2v. c. an object with a mass of 2m and a velocity of 3v. d. an object with a mass of m and a velocity of 4v.
an object with a mass of 2m and a velocity of 3v
What is necessary for a change in velocity?
an unbalanced force
In the United States, which one of the following sectors consumes the most energy? a. residential b. commercial c. industry d. transportation
industry
What term refers to the tendency of an object to remain at rest or in uniform, straight-line motion?
inertia
According to Newton's second law, an object's acceleration is _____ _____ to its mass.
inversely proportional
The total energy of a(n) _____ system remains constant.
isolated
Energy and work are measured in the SI unit called _____.
joule
The unit N•m is given the special name of _____.
joule
What is the SI unit of energy?
joule
The newton unit of force is equal to _____ in standard units.
kg•m/s²
Mechanical energy consists of _____ and potential energy.
kinetic
The inertia of an object is related to its _____.
mass
_____ is a measure of inertia.
mass
If a submerged object displaces a volume of liquid of greater weight than its own and is then released, what will the object do?
rise to the surface and float
Work and energy are _____ quantities.
scalar
Work is a _____ quantity.
scalar
If a submerged object displaces an amount of liquid with a weight less than its own, when the object is released, it will _____.
sink
Define renewable energy sources
sources of energy able to be replaced through ongoing natural processes
The stopping distance of an automobile on a level road depends on the _____ of the speed.
square
The coefficient of _____ friction is generally greater than the coefficient of _____ friction.
static, kinetic
What is energy?
the ability to do work
If motor A has twice as much horsepower as motor B, then motor A has the power capability to do ___.
the same work in half the time
If motor A has twice as much horsepower as motor B, then motor A has the power capability to do _____.
the same work in half the time
Mechanical energy is _____.
the sum of kinetic and potential energies
Define conservation of total energy
the total energy of an isolated system remains constant
A child's toy floats in a swimming pool. The buoyant force exerted on the toy depends on the volume of:
the water displaced
The angular momentum of an object is not conserved if the object is acted upon by unbalanced _____.
torque
G is thought to be a(n) _____ gravitational constant.
universal
Define Work
using a force to move an object a distance
Forces are _____ quantities.
vector
When a constant net force is done on an object, the object's _____ changes.
velocity
Mass is related to an object's _____.
weight, inertia, and density
An object will sink in a fluid if its average density is _____ than that of the fluid.
greater
Which of the following renewable energy sources currently produces the most energy? a. wind power b. solar power c. hydropower d. tidal power
hydropower
What is the state of an object being acted upon by an unbalanced force?
in motion with a constant velocity
A horsepower is equal to about _____ kW.
0.75
A change in which of the following affects the weight of an object? a. momentum b. acceleration due to gravity c. unbalanced force d. change in velocity
acceleration due to gravity
Newton's first law of motion (law of inertia)
An object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force.
Car B is traveling twice as fast as car A, but car A has three times the mass of car B. Which car has greater kinetic energy?
Car B
Common forms of Energy
Chemical, electrical, gravitational, nuclear, electromagnetic and thermal
Define kinetic energy
Energy possessed by an object in motion
Newton's Third Law of Motion
For every action there is an equal and opposite reaction action on different objects.
Define conservation of mechanical energy
In the absence of friction, the total mechanical energy remains the same
Which is true about the acceleration due to gravity? a. It is a universal constant. b. It is a fundamental property. c. It decreases with increasing altitude. d. It is different for different objects in free fall.
It decreases with increasing altitude.
What is true about the constant G? a. It is a very small quantity. b. It is a force. c. It is the same as g. d. It decreases with altitude.
It is a very small quantity.
According to Newton's second law of motion, when an object is acted upon by a net unbalanced force, what can be said about the acceleration?
It is inversely proportional to the object's mass.
Power is expressed by which of the following units? a. J/s b. N•m c. W•s d. W/m
J/s
Which of the following is a unit of work? a. W b. J•s c. N/s d. N•m
N•m
Define gravitational potential energy
Potential energy that depends on the height of an object
A change in linear momentum requires which of the following? a. a change in velocity b. an acceleration c. an unbalanced force d. all of these
all of these: • a change in velocity • an acceleration • an unbalanced force
What is a possible state of an object in the absence of a net force? a. at rest b. zero acceleration c. constant speed d. all of these
all of these: • at rest • zero acceleration • constant speed
Define Energy
The ability to do work.
Newton's Second Law of Motion
The acceleration of an object depends on the mass of the object and the amount of force applied. Units of effect: m/s²
Define potential energy
The energy an object has because of its position or location.
For every action force, there is which of the following? a. a friction force b. an opposite but not necessary equal force c. an equal and opposite force d. an unbalanced force
an equal and opposite force
Define power
The time rate of doing work.
Explain conservation of momentum using Newton's second law.
The total linear momentum of an isolated system remains the same if there is no external, unbalanced force acting on the system.
Which is true of the force pair of Newton's third law? a. The two forces never produce an acceleration. b. The two forces act on different objects. c. The two forces always cancel each other. d. The two forces are in the same direction.
The two forces act on different objects.
Which one of the following would not be classified as a total alternative fuel source? a. photocells b. gasohol c. windmills d. wood
gasohol
Define Joule
Unit of energy
Define watt
Unit of power = 1 kg m²/s³ or 1 J/s
When you throw an object into the air, is its return speed just before hitting your hand the same as its initial speed? (Neglect air resistance.)
Yes
A net force can produce ______.
a change in velocity magnitude
Define horsepower
a common unit of power equal to about 746 watts
Angular momentum is conserved in the absence of which of the following? a. inertia b. gravity c. a net torque d. linear momentum
a net torque
Define torque.
a twisting force that tends to cause rotation
Define kilowatt-hour
a unit of energy equal to the work done by a power of 1000 watts operating for one hour
Persons A and B do the same job, but person B takes longer. a. Who does the greater amount of work? b. Who is more "powerful"?
a. They both do equal amounts of work. b. Person A
On which of the following does the speed of a falling object depend? a. mass b. √∆h c. ½mv² d. parallel difference
b
A net force _____. a. is capable of producing a change in velocity. b. can produce motion. c. is a scalar quantity. d. can both produce motion and is capable of producing a change in velocity.
can both produce motion and is capable of producing a change in velocity
A force is a quantity that is _____ of producing motion or a change in motion.
capable
In the U.S., _____ is the most consumed fuel in generating electricity.
coal
Galileo concluded that objects (could or could not) remain in motion without a net force?
could
Energy cannot be _____.
created or destroyed
When the height of an object is changed, the gravitational potential energy _____.
depends on the reference point
Newton's third-law force pair acts on _____ objects.
different
The kilowatt-hour (kWh) is a unit of _____.
energy
Define kinetic energy.
energy of motion ½mv²
Alternative energy sources
energy sources that are alternatives to fossil fuels and better for the environment (wind, solar and water energy) (BUT very expensive)
When work is done there is a change in _____, and the amount of work done is _____ to the change of energy.
energy, equal
Gasohol is gasoline mixed with _____.
ethanol (alcohol)
Renewable energy sources cannot be _____.
exhausted
A child's cubic play block has a mass of 113 g and sides of 5.6 cm. When placed in a bath tub full of water, will the cube sink or float?
float
An object will remain at rest or in uniform, straight-line motion if not acted upon by a(n) _____.
force
The vector quantity capable of producing motion or a change in motion is _____.
force
Define momentum in words and with a formula.
momentum (p) is the product of the mass (m) and the velocity (v) of an object p=mv
Milk is _____ dense than the cream that floats on top.
more
Kinetic energy is commonly referred to as the energy of _____, and potential energy as the energy of _____.
motion, position
Work is done on an object when it is _____.
moved
A pitcher throws a fastball. When the catcher catches it, _____.
negative work is done.
The total linear momentum is not conserved if there is a(n) _____ force acting on the system.
net or unbalanced
Work is equal to the force times the ____ distance through which the force acts.
parallel
Energy in a rock sitting on a cliff is _____.
potential
The time rate of doing work is called _____, and is expressed in units of _____.
power, watts
What is work?
process by which energy is transferred from one object or system to another.
If a submerged object displaces a volume of liquid equal to its weight and is then released, what will the object do?
remain at its submerged position
When energy is transferred from one object to another, _____ is done.
work