# Circular motion and SHM

• Created by: argyrou
• Created on: 03-05-18 10:39
What is the speed equation for uniform circular motion?
V=2_r/T or 2_rf
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What is the equation for angular speed _ in words and letters?
_=angular displacement/time taken or _=_/t
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What are the units for angular speed _?
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What is the equation for angular displacement _?
_=2_ft
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What is _? (include equation)
Its angular speed, _=2_f
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What is the equation for centripetal acceleration?
a=v²/r = _²r
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What is the angle between the centripetal force and the object velocity?
90 degrees, right angle
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Why is no work done by centripetal force on the object?
No work is done because theres no displacement on direction of force
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What is the equation for centripetal force?
F=mv²/r = m_²/r
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When at the top of a hill, what is the resultant centripetal force equal to?
mv²/r=mg-s (where s is the reaction force of weight)
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On a roundabout, entripetal force is provided by sideways force of friction between vehicles tyres and road surface. What is this force of friction equal to?
force of friction = mv²/r
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In order for a car to not slip or skid due to the friction what must the terms for force be?
the force of friction must be smaller than the limitting value of friction (_R)
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On a banked track, what must v² be equal to in order for there to be no sideways friction?
v²=g r tan_
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At the bottom of a rollercoaster, what is the centripetal force equal to?
mv²/r=s-mg (where s is the reaction force of weight)
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What is the equation for v² to work out the maximum speed of a swing?
v²=2gh
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On a big wheel rollercoaster, why do people feel weightless and what is the equation for the centripetal force?
Gravity is pulling you down, but there is no reaction force to balance gravity because it now acts downards. mv²/r=mg+R
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What is amplitude?
max displacement
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What are free vibrations?
the term for the oscillations when the amplitude is constant so there are no frictional forces present
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What is the equation for phase difference?
2__t/T (where_t is time between successive instants when 2 objects are at max displacement in same direction)
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What needs to be equal in the equation for phase difference in order for 2 objects to oscillate in phase?
_t=T
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What is the gradient of a displacement-time graph?
velocity
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When is velocity greastest when looking at a diplacement-time graph?
velcity is greated when gradient of displacement-time graph is greatest.
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What is the gradient of a veloctity-time graph?
acceleration
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When is acceleration zero when looking at a velocity-time graph?
when gradient of velocity-time graph is zero
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Define simple harmonic motion
An oscillating motion in which acceleration is - proportional to displacement - always in the opposite direction to displacement
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What is the defining equation for simple harmonic motion?
a=-_²x
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What is the relationship between time period and amplitude of an oscillating motion?
No relationship, time period does not depend on amplitude of oscillating motion.
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What are 2 ways frequency of oscillation of a loaded spring can be reduced?
-Adding extra mass - Using weeker springs
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What is the equation for restoring force of a spring?
T=-Kx (where K is the spring constant)
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What is the equation for acceleration?
-Kx/m
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what is _² as an equation for a mass-spring system?
K/m
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What is the relationship between time period and gravity?
no relationship. A mass-spring system on moon would be the same mass-spring system on earth
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What is the equation for time period of oscillations of a mass-spring system?
T=
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What is the restoring force of the simple pendulum?
F=-mgsin_
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What is _² equal to for a pendulum?
g/L
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How can time period be increased of a pendulum?
by increasing length of the pendulum
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What is the equation for time period for a pendulum in osillation?
T=
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What is the equation for total energy for a mass-spring system?
KA²/2
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What is the equation for potential energy of a mass-spring system?
Kx²/2
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What is the equation for kinetic energy of a mass-spring system?
K(A²-x²)/2
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What is the simple harmonic speed equation?
v=__((A²-x²)
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What does an enegy-displacement graph look like in terms of Ek and Ep?
graph
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What does it mean to be a freely oscillating object?
Oscillates at constant amplitude with no friction acting on it
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When is motion said to be damped?
If dissipative forces are present
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What does light damping look like?
graph
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what does critical damping look like?
graph
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What does heavy damping look like?
graph
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What is a periodic force?
force applied at regular intervals
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Define natural frequency
When a system oscillates without periodic force applied to it
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Define forced vibrations
When a periodic force is applied to it, ther response depends on frequency of periodic force
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What is the phase difference of a system oscillating at max amplitude?
phase difference between displacement and periodic force is _/2
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Define resonance
system in resonance is when periodic force is exactly in phase with velocity of oscillating system
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What happens to amplitude and frequency the lighter the damping?
-the larger the max amplitude becomes at resonance -the closer the resonant frequency get to the natural frequency
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## Other cards in this set

### Card 2

#### Front

What is the equation for angular speed _ in words and letters?

#### Back

_=angular displacement/time taken or _=_/t

### Card 3

#### Front

What are the units for angular speed _?

### Card 4

#### Front

What is the equation for angular displacement _?

### Card 5

#### Front

What is _? (include equation)

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