Oscillations and Vibrations l Flashcards
What is Energy?
Ability to do work, such as the capacity to move an object by using force.
What is the S.I unit of energy?
J (Joule)
What is Kinetic Energy?
Form of energy that an object has by reason of its motion. Objects that speed up gain Kinetic Energy.
What is the abbreviation for kinetic energy?
Ek (in J)
What is potential energy?
Stored/ Latent Energy
What is the abbreviation for Gravitational potential energy.
Eg
What is the abbreviation for Elastic potential?
Es
Describe gravitational potential energy.
Potential energy that makes something have a tendency to fall down.
What is the formula for Eg?
Eg = mgy
g= acceleration due to gravity in m/s2
y =height above some reference height
What is the formula for Ek?
Ek= 1/2mv2
Describe the energy transformation of a dropped object when it is about to be DROPPED.
Ek = 0 (since v=0)
EG = Max
Describe the energy transformation of a dropped object when it is about to be HIT THE GROUND.
Ek =Max
EG= 0 (since y=0)
As object falls, it loses _______________ energy and gains ________ energy.
As object falls, it loses gravitational potential energy and gains Kinetic energy.
As object falls and accelerates, the ___________ energy is being transformed into ________ energy.
As object falls and accelerates, the gravitational potential energy is being transformed into kinetic energy.
True or False: the total energy of a dropped object is CONSERVED and remains constant?
True!
Etotal(stays the same) = EG (decreases) + Ek(increases)
What is Elastic potential energy?
Potential energy that an object has when it is displaced from its equilibrium position.
What are three ways we can call the type of FORCE in the Es?
Elastic force
Spring force
Restoring force
What is the abbreviation of Elastic potential energy?
Es
What does Fs stands for? Draw a diagram.
It is the elastic force that pulls object back towards 0. (in N)
The amount of elastic force for a spring is very predictable, what is it called?
Linear elastic behavior
What is Hooke’s Law?
Hooke’s law, law of elasticity states that, for relatively small deformations of an object, the deforming force will be proportional to the size of the deformation (ex: 2m of deformation will yield 2Fs)
What is the formula for elastic force?
Fs= -kx
Fs= elastic force (in N)
x = distance of displacement (in m)
k = elastic constant (in N/m)
What is the difference between a + and - in the formula Fs= +kx and Fs=-kx Draw it!
The force always acts in a direction that is opposite of the objects displacement direction.
What is the formula for elastic potential energy?
Es= 1/2kx2
Es in J
k= elastic constant N/m
Give three materials that possess elasticity.
Springs
Cheeks
Elastic bands
When an elastic material is compressed or expanded it possess ____________ energy.
elastic potential energy
When the material/ object is released, that elastic potential energy begins to be transformed into _______________.
Kinetic energy (the elastic material begins to move)
What is work?
Work is done by a force on an object to make it move.
What is the abbreviation of work?
W (in Joules)
What would be an example of doing work by kicking?
If I kick it, I am working on it and making it gain Ek (O+ Wkick= Ek)
What would be an example of doing work to move an object on a table.
As the object moves along the table top, it slows down because friction does negative work on it, making it lose Ek (Ek+(-Wfriction) = ))
How do you find the Total mechanical energy at the end of a work process?
Etme(initially) + W = Etme (at the end)
What is the formula of Work?
W = F.d.cosθ
W in J
F in N
d distance object moves m
θ = angle between the force and the direction of motion of object (in degrees)
If θ is = 0 what does it mean in terms of the direction of work?
If θ the angle between the direction of motion and the force is 0 than 100% of that force will go in that direction.
What is Power?
Rate at which energy is produced or consumed/used.
What is the formula for Power?
P = E/t
E in J
t in s
What is intensity?
Measure of how power is distributed spatially (thus how energy is distributed in space)
What is the formula for intensity?
I= PA
I in W/m2
Power in W
A in m
What is the formula of power for an isotropic source?
I = P/4.pi.r2
r in m
An ____________ source of a sound wave produces _______ wavefronts
An isotropic source of a sound wave produces equal wavefronts on all sides
In an isotropic source, for every distance r around the object, the energy should be __________________.
Evenly distributed
What is the name of the restoring force of springs?
Elastic force
What is the name of the restoring force of a pendulum?
gravity
What is the name of the restoring force of a tuning fork?
elastic force
Energy can be __________or __________from one form to another.
Transformed or Transferred
