Physics 2: momentum, energy rotational motion Flashcards
inertia in motion. The product of the mass of an object and its velocity.
momentum
Momentum =
mass x velocity OR if direction is not a factor, mass x speed
If the momentum of an object changes then either the ___ or the ____ or both change.
mass or velocity
also changes momentum
how long a time the force acts
both _____ and __ ____ are important in changing momentum
force and time interval
impulse =
impulse = the quantity of force x time interval (Impulse = Ft)
change in momentum
impulse
When an object ____ the impulses are greater than when the object comes to a stop
bounces
only an impulse ____ to a system can change the momentum of the system
external
Momentum has both:
direction and magnitude
In the absence of an external force, the momentum of a system remains unchanged
Law of Conservation of Momentum
colliding objects rebound without lasting deformation or generation of heat
Elastic collision
when objects become entangled during the collision; characterized by deformation, or generation of heat, or both.
Inelastic collision
Net momentum ____ ____ in any collision regardless of the angle between the paths of the colliding objects
remains unchanged
force x distance
Work
the unit of measurement of work
joule
amount of work done per time it takes to do it.
Power = work done/time interval
The unit of power
watt (joules per second)
something that enables an object to do work
Energy
Energy is measured in ____.
joules
2 common forms of mechanical energy:
- energy due to the position of something
2. the movement of something
energy stored and held in readiness
potential energy
potential energy due to elevated positions
gravitational potential energy
potential energy can change into ____ ____.
kinetic energy
energy of motion
kinetic energy
1/2 mass x speed x speed =
kinetic energy
net force x distance =
kinetic energy
work = change in ____
kinetic energy
Energy cannot be created or destroyed; it may be transformed from on form into another, but the total amount of energy never changes
Law of Conservation of Energy
device for multiplying forces or changing the direction of forces. They work on the principle of conservation of energy
machine
one of the simplest machines
lever
if the little work done by friction is small enough to neglect, then the work input will equal work output
(Fd)input = (Fd)output
point of support on which the lever rotates
fulcrum
when the fulcrum is close to a load,
a small input force will produce a large output force
useful energy output/total energy input
efficiency
linear speed of something moving along a circular path
tangential speed
____ ____ is directly proportional to the distance from the axis for any given rotational speed
tangential sped
units of tangential speed
m/s or km/h
Rotational rates
RPM revolutions per minute
When tangential speed undergoes a change
tangential acceleration
the property of an object to resist changes in its rotational state of motion
rotational inertia
rotational inertia depends on ____ about axis of rotation
mass
the rotational counterpart of force
torque
if you want to make a stationary object rotate apply ___
torque
lever arm x force =
torque
the average position of all the mass that makes up the object
center of mass
used to express center of mass. It is the average position of weight distribution
center of gravity
ideal way to increase stability
wide BOS and lower COG
rotational inertia x rotational velocity
Angular momentum
