Conceptual Physics-Laws of Motion Unit-Final Test Flashcards
What is a force?
a push or a pull
What is inertia?
the tendency of an object to resist changes in its motion; Newton’s first law
Will a force have the same effect on different masses?
the same force will cause less massive objects to accelerate more; mass is a factor in acceleration just as force is
How does mass affect inertia?
more mass means more inertia; direct relationship
What is the relationship amoung the quantities: force mass, and acceleration?
force=mass x acceleration; if mass increases, so does force; if force increases, so does acceleration; if mass increases, acceleration decreases
How is an object’s center of mass located
at the balance point, where plumb lines connect, point around which all mass is centered
What happens if the support base is removed from the center of mass?
the object will fall over
Do different objects fall at different rates towards earth? If so, what causes the difference?
No, Gravity has a constant rate of acceleration of 10 m/s/s. The only difference would be air resitance/friction.
How can the amount of gravitational force actin on an object be determined?
Gravitiy is always 10 m/s/s
gravitational potential is different depends on hieght
What is the difference between weight and mass?
mass is constant; wieght is a force, pull of gravity on mass
What is meant by balanced and unbalanced forces?
balanced: no change in motion; equal and opposite
unbalanced: object accelerates; unequal, always change motion
What does it mean to say that an object is accelerating?
It’s speeding up, slowing down, stopping, starting, or changing direction; it’s speed or direction is changing
What causes a stationary object to remain stationary?
balanced forces
Under what conditions will an object in motion continue to move?
If the forces are balanced
What is meant by the statement: for every action there is an equal and opposite reaction?
forces come in action reaction pairs; if you push off a surface in zero gravity, you push towards the wall, but you move away from it.
What determines the amount of friction acting between two objects?
The types of surfaces: rough surfaces have higher mu
In what direction is friction applied in an object?
IN the opposite direction of its motion
What would a graph of two surfaces with a lot of friction look like, compared t surface will little friction?
The graph with lots of friction would have a steeper slope, while the one with little friction would have a flatter/lower slope.
How is the kinetic energy of an object determined?
How fast it moves and its mass
How is the gravitational potential energy of an object determined?
how high it is off the ground
What does it mean to say that energy is conserved?
total energy stay sthe same
What does a graph of Newton’s second law look like?
acceleration on y, force on x: exponential slope, positive trend, (up on y, forward on x)
acceleration on y, mass on x: exponential slpe, negative trend (down on y, forward on x)
What is momentum, and how would you measure it?
quantity of motion, kg m/s (mass x velocity)
what does it mean to say that momentum is conserved?
during collisions: objects transfer momentum to other objects; total momentum is constant
Is a force required to make an object move in a circular path? If so, where does it need to be applied
yes, towards the center of the circular path, or else it would just go straight, as in the first law
If an object leaves a circular path, what direction will it travel? Explain how to draw a diagram of this.
draw a circle or curve to represent the path, marking the center of the circle/curve. Draw a line from the center to the point at which the object left the path, then draw a tangent to that point. The direction is that which the object was traveling at the point at which it left the path.
distance unit
d
meters m
velocity/speed unit
v
meters/second m/s
time unit
t
seconds s
force unit
F
Newtons N
mass unit
m
kilograms kg
energy unit
E
joule J
work unit
W
joule W
weight unit
w
Newtons N
momentum unit
p
kilograms meters/second kg m/s
The Law of Conservation of energy
Energy is not created or destroyed, but it can change forms.
Energy changes forms when…
work is done
What changes an object’s motion?
A net force
In absence of a net force, an object…
will stay at rest or will move in a straight line at a constant speed
inertia def
a measure of an object’s tendency to resist a change in motion
Kinetic energy def
energy that is a result of motion
Potential energy def
energy that is a result of position, chemical makeup, or the compression or elongation of an object
Centripetal force def
force that causes an object to move in a circular path, pushes or pull an object toward the center of a circular path
centrifugal force def
a specific name for the force of inertia on an object that is moving in a circular path
When an object exerts a force on a second object, the second object…
exerts an equal force on the first object, but in the opposite direction
massive objects have more or less inertia than less massive objects?
more
Force can be illustrated as a…
vector (direction and size of force)
net force def
sum of all forces action on an object
Newton’s Second Law
Acceleration: Objects accelerate when an unbalanced force is applied; it will move in the direction of the force at a speed that is in a direct relationship with the force and an inverse relationship with the object’s mass
Newton’s First Law
Inertia: When forces are balanced- an object at rest will stay at rest and an object in motion will stay in motion at a constant speed in a straight line path
Newton’s Third Law
Action-Reaction Pairs: For every action there is an equal and opposite reaction; theses forces act on different objects (than the object exerting them)
work is done when…
a force acts on an object in the direction in which the object is moving
What is the difference between acceleration and constant speed?
Acceleration is when there is a change in motion.
Constant speed does not change.
What is the equation for momentum?
momentum= mass x velocity
p=mv
What is a sticky collision?
It is when two objects collide and begin to move as one; they ‘stick together’ after the collision.
What is friction
a force that opposes motion (or attempted motion) of objects that are touching
what is the difference between sliding friction and static friction
sliding; objects slide past each other
static: stationary; stay in one place
Sliding friction causes some energy to be changed into…
thermal energy
coefficient of friction def/equation
mu= force to slide/upward force
Objects rotate around…
their center of mass
velocity def
the rate at which you change position; v=d/t
velocity formula: distance=
speed x time
velocity formula: time=
speed divided by distance
force formula: force=
mass x acceleration
force formula: mass=
force divided by acceleration
force formula: acceleration=
force divided by mass
Acceleration formula: acceleration=
(final velocity - initial velocity)/time
momentum formula: momentum=
mass x velocity
momentum formula: velocity=
momentum/mass
Collisions formula: momentum before collision=
momentum after collision
