Physics final review Flashcards
what must happen to all potential energy before it becomes useful
conversion to kinetic energy
why do objects at rest not move
because all forces acting on them are balanced
how can an object gain motion
if forces become unbalanced (one force is greater than another), then an object can gain motion
force:
a push or a pull on an object.
F=ma
net force:
an object has many forces acting upon it; the sum of these forces is called the netforce
F=ma
the effect of mass:
a factor that influences the rate of acceleration/deceleration of an object
force and work:
when a force is applied to an object, causing that object to move, then work is done on the object.
- object must move in order for work to be done
how to get the work from a force and distance graph
-area
force x d
energy:
-the ability to do work
-if an object has energy, then it can do work by transferring that energy to another object
- all physical processes involve the transformation of one type of energy into another
what are the types of energy
potential(position) and kinetic (motion)
- further energy types under these
two catagories
types of potential energy
- electrical
- chemical
- gravitational
- nuclear
- elastic
- thermal
types of kinetic energy
- thermal
- sound
- radiant
- elecrical
- mechanical
kinetic energy:
- energy of motion
-anything that is moving can be made to do work because of its motion
-depends of the speed and mass of an object
for speed conversions what is the number you divide/multiply by?
- to convert from km/h to m/s, divide by 3.6
- to covert m/s to km/h, multiply by 3.6
first law of thermodynamics
energy cannot be created or destroyed, only transformed from one for to another.
second law of thermodynamics
no energy conversion is 100% efficient; some energy is always lost as heat when converting from one form to another
energy conversion
energy must often be converted from one form to another to do work
vector quantities:
force, velocity, acceleration, displacement, and momentum.
vector:
a quantity that has both magnitude and direction
scalar:
A scalar is any quantity that has magnitude but no direction
examples of scalars
volume, density, speed, energy, mass, and time
distance
what is mechanical energy?
the sum of gravitational and kinetic energy
Em = Ep + Ek
in an isolated system, what happens to the mechanical energy
the total mechanical energy remains constant
open system
matter and energy can flow in and out of the system
closed system
matter can not transfer in or out of the system but energy can
isolated system:
neither matter nor energy can flow in and out of the system
steam engine:
thermal energy converted into kinetic energy to do work
