Physica
product of force and distance
work
formula for total work
positive work - negative work
energy possessed by an object by virtue of its position, relative to the ground. it is equal to the work needed to move an object from the ground to a certain height
potential energy
energy possess by an object by virtue of its motion
___ of a body moving with a linear motion
kinetic energy
thin ring, axis through center perpendicular to plane of ring
I = mr²
thin ring, axis along diameter
I =1/2(mr²)
solid disk, axis through center perpendicular to plane of ring
I = ½mr²
solid disk, axis along a diameter
I = ¼mr²
solid cylinder, axis of the cylinder
I = ½mr²
hollow cylinder, axis of cylinder
R outer radius
r inner radius
I = ½m(R² - r²)
solid sphere, axis along a diameter
I = ⅖mr²
thin walled hollow sphere, axis along a diameter
I = ⅔mr²
uniform thin rod of length L, axis perpendicular to rod at center
I = 1/12 mL²
uniform thin rod of length L, axis perpendicular to rod at end
I = ⅓mL²
rectangular plane, axis through center
a = length
b = width
I = 1/12 m(a² + b²)
rectangular plane, axis through edge
I = ⅓ma²
the rate of using energy
power
formula for power P
P = mgh / t
states that energy cannot be created nor destroyed but it can be change from one form to another
law on conservation of energy
the product between force applied on body and the time it was applied
impulse
the product between mass of the body and its velocity
momentum
every material particle has ______ when it is in motion, and ______ impulse produces a change in momentum
momentum, impulse
relation between impulse and momentum
in every collision where the velocity is changed, the momentum lost by one body or set f bodies is equal to the momentum gained by another body or set of bodies
Law on Conservation of Momentum
negative ratio between the relative velocities of two colliding objects after and before they collide
always lies between 0 and 1
coefficient of restitution (e)
conserves the kinetic energy after the collision
relative velocities before and after the collision ae equal, e=1
perfectly elastic bodies
stick together after the collision
v1 = v2
e =0
perfectly in-elastic bodies
branch of mechanics which deals with bodies in motion
dynamics
study of motion of bodies without reference to the forces that causes motion
kinematics
study of motion of bodies and the forces that causes the motion
kinetics
change of velocity with respect to time
acceleration
motion of any body that is given an initial velocity and firing angle, the travels and follows a path determined entirely by the effects of gravitational acceleration and air resistance
projectile motion
is a motion in which the body is moving in a circular motion but the body has no horizontal or vertical translation
rotation
when a body moves in a uniform velocity along a curve path of radius r, has radial inward acceleration of magnitude v²/r
centrifugal force
specified merely that stress is proportional to strain
Hooke's Law
maximum displacement of the particles of the medium through which the waves passes on either sidesof its equilibrium positions
amplitude
highest point of the wave
crest
lowest point of the wave
through
number of waves that passes a given point per second
frequency
is the time required for one complete wave to pass a given point
period
is the distance it moves per unit time
depends upon the kind of wave and the properties of the medium
speed of the wave
is produced when the particles of the medium move back and forth perpendicular ot the direction of the wave
transverse wave
is formed when the particles of the medium moved back and forth in the same direction as the wave
compressional wave
longitudinal
is any substance that can flow, it is either a liquid or a gas
fluid
is defined as mass per unit volume
density
is the volume occupied per unit mass of the fluid
specific volume
is defined as weight per unit volume
specific weight
fluid pressures are measured in respect to two pressure references
atmospheric pressure
zero pressure
is the pressure caused by gases which composes in the atmosphere
atmospheric pressure
is the pressure measured with respect to atmospheric pressure or barometric pressure
measured using gages or manometer
gage pressure
is the pressure measured with respect to the zero pressure references
absolute pressure
ratio of density of a substance to the density of water at a reference temperature of 4°C
relative density
specific gravity
heat is transfered by means of collision between rapidly moving molecules at the hot end of a moving body of matter and the slower the molecules at the cold end
conduction
heat is transferred from one plate to another by the actual motion of hot fluid (liquid or gas)
convection
heat energy is carried by the electromagnetic waves emitted by every object
radiation
a perfect absorber of radiation is called the _______. its emissivity is equal to one
blackbody