AP Physics 1 Laws
Newton's first law of motion - law of inertia - ANS"An object continues in a state of rest, or in a
state of motion at a constant speed along a straight line, unless compelled to change that state
by a net force."
If you don't apply a force to an object at rest or in motion, it will stay at rest or in that same
motion along a straight line. Forever.
Inertia - ANSnatural tendency of an object to resist a change in its motion.
Because mass has inertia, it resists changing its motion, which is why you have to start applying
forces to get velocity and acceleration. Mass ties force and acceleration together.
Newton's second law of motion - ANSThe acceleration of an object is directly proportional to the
net force applied to the object and inversely proportional to the mass of the object: a = Fnet/m.
A larger force produces a larger acceleration and a larger mass produces a smaller
acceleration. Force is directly related to acceleration.
Newton's third law of motion - law of action-reaction pairs - ANSFor every action there is an
equal and opposite reaction FAB = FBA. Therefore, if one object exerts a force on a second
object, the second exerts an equal and oppositely directed force on the first one.
The action-reaction pair must be the same type of force (gravity) and must involve the same two
objects (apple and Earth).
Newton's law of universal gravitation - ANSEvery mass exerts an attractive force on every other
mass. If the two masses are m1 and m2 and the distance between them is r, the magnitude of
the force (F) is F = Gm1m2/(r squared), where G is a constant equal to 6.67 x 10-11 N(m
squared)/(kg squared).
The force of gravity is directly proportional to the product of the masses and inversely
proportional to the square of the distance between them.
Work-energy theorem - ANSIn physics, you can relate the work done on an object and the
change in the object's kinetic energy: W = (change in KE) = ½m (change in v squared).
The application of a force over a distance can be seen as the use of energy to produce work.
For example, if two people push identical shopping carts, but one person does more work, you
can calculate how much faster their cart will go than the other. Work is related to velocity.
Law of conservation of energy - ANSEnergy can neither be created nor destroyed; but, can be
changed from one form to another. In a closed system, the amount of energy is fixed, Ei = Ef.
You can't create any more energy inside the system or destroy any of the energy that's already
in there. But you can convert the energy you have from one form to another (and sometimes
back again).
Newton's first law of motion - law of inertia - ANS"An object continues in a state of rest, or in a
state of motion at a constant speed along a straight line, unless compelled to change that state
by a net force."
If you don't apply a force to an object at rest or in motion, it will stay at rest or in that same
motion along a straight line. Forever.
Inertia - ANSnatural tendency of an object to resist a change in its motion.
Because mass has inertia, it resists changing its motion, which is why you have to start applying
forces to get velocity and acceleration. Mass ties force and acceleration together.
Newton's second law of motion - ANSThe acceleration of an object is directly proportional to the
net force applied to the object and inversely proportional to the mass of the object: a = Fnet/m.
A larger force produces a larger acceleration and a larger mass produces a smaller
acceleration. Force is directly related to acceleration.
Newton's third law of motion - law of action-reaction pairs - ANSFor every action there is an
equal and opposite reaction FAB = FBA. Therefore, if one object exerts a force on a second
object, the second exerts an equal and oppositely directed force on the first one.
The action-reaction pair must be the same type of force (gravity) and must involve the same two
objects (apple and Earth).
Newton's law of universal gravitation - ANSEvery mass exerts an attractive force on every other
mass. If the two masses are m1 and m2 and the distance between them is r, the magnitude of
the force (F) is F = Gm1m2/(r squared), where G is a constant equal to 6.67 x 10-11 N(m
squared)/(kg squared).
The force of gravity is directly proportional to the product of the masses and inversely
proportional to the square of the distance between them.
Work-energy theorem - ANSIn physics, you can relate the work done on an object and the
change in the object's kinetic energy: W = (change in KE) = ½m (change in v squared).
The application of a force over a distance can be seen as the use of energy to produce work.
For example, if two people push identical shopping carts, but one person does more work, you
can calculate how much faster their cart will go than the other. Work is related to velocity.
Law of conservation of energy - ANSEnergy can neither be created nor destroyed; but, can be
changed from one form to another. In a closed system, the amount of energy is fixed, Ei = Ef.
You can't create any more energy inside the system or destroy any of the energy that's already
in there. But you can convert the energy you have from one form to another (and sometimes
back again).
