Notes over Circular Motion. What is circular motion? The motion of things that are
traveling in a circle. Notice that this is similar to projectile motion but instead of ...
Circular Motion : Notes-5. When any object moves in a circle at a constant speed,
there must be a force acting on it. That force is directed towards the center of ...
Circular Motion Lecture notes. 1. Force is centrally directed, causes ΔV (accel).
Ergo accel is centrally directed a. Show vid clips and identify direction of force: ...
Circular Motion. Dr A. C. H. Cheung∗. Trinity College, Cambridge. 25th August,
2010. 1 Introduction. In this lecture, we shall study uniform circular motion, which
...
earth, moon. Charged particles moving in a magnetic field. Rides to car rounding a curve. Blood circulating. Further mor
net force acting upon the object are displayed at the bottom of the screen. The animation can be. started, paused, conti
1. Uniform Circular Motion (Ch 6). •. A force, Fr , is directed toward the center of
the circle. •. This force is associated with an acceleration, ac. •. Applying Newton's
...
of a circle, Newton's Second Law, and uniform accelerated motion. Notes to the
Teacher. Uniform circular motion is the motion of an object moving at a constant ...
Chapter 5 - Uniform Circular Motion. ⢠Velocity: if constant speed (magnitude), but changes direction â acceleration
Studying Circular Motion. TEACHER NOTES. Activity title: STUDYING
CIRCULAR MOTION. Subject: Physics - Class XI. Student age: 16-18 years.
Estimated ...
Physics 6A. Prepared by ... We have a formula that we will use often for circular
motion. For an object ... the centripetal acceleration at the bottom of the test tube.
Uniform circular motion describes the movement of an object in a circular path at
a ... The force required to keep an object in uniform circular motion is directed.
(1) Have enough energy to reach point C. (2) Have sufficient high centripetal
force to maintain the circular motion at C. Consider Conservation of energy ; ...
4 uniform circular motion ! acceleration is of constant magnitude and directed
toward the circle's center ! something must provide the force tension in the string
...
executing circular motion, determine: (1) if the motion is clockwise ..... v = ωr . (13)
. Note that v, ω, and r are either positive or zero, never negative. We can derive ...
Uniform circular motion: motion in a circle of constant ... For an object to be in
uniform circular motion, Newton's ... Note: Don't count the centripetal force as an.
Isaac Newton1 and Richard Conn Henry2 ... Isaac Newton and Richard Conn Henry .... R. S. Westfall, Never at Rest: A Biography of Isaac Newton (Cambridge ...
And if there is acceleration, there is a net force (Newton's. First Law!) • If motion in
circle at const speed, force towards center. • Can calculate this force in terms of ...
Circular motion. Isaac Newtona) and Richard Conn Henryb). (Received 20
October 1999; accepted 30 November 1999). An extraordinarily simple and ...
Aug 26, 2015 - Department of Physics, University of North Carolina at Pembroke, Pembroke, NC 28372. .... taught at the undergraduate, and even high-school, level. ..... The original statement of locality is attributed to Issac Newton13 âTis.
Centripetal Force and Uniform Circular Motion. Introduction. This lab gives ideas
of the uniform circular motion. This has a different concept from the previous ...
Uniform circular motion is motion in a circle with constant speed. ... Which free-
body diagram in Figure 5.11 correctly shows the force(s) acting on the Earth (E)
as ...
Instantaneous velocity in any type of curved motion is tangent to the curve. ...
center. 2 c v a r. = Centripetal means center seeking. Force: If an object is
changing ...
... motion using ordinary appliances, train toy, digital camera and android- ..... 8, No. 1, 2000. [34] Goldhaber, D. D. Does Teacher Certification Matter? High.
An object moving in circular motion is inherently accelerating (centripetal
acceleration). It must therefore have a net force continually acting on it. We call
this net.
Angular acceleration vs. Centripetal acceleration
Angular acceleration arises when a spinning object is speeding up or slowing down its spin. (Example: A car tire as a car is speeding up) Centripetal acceleration has to do with the fact that the tangential velocity of an object is always changing even if the speed of the spin is not. (Example: Earth’s orbit around the sun)
The centripetal force (which is the net force causing circular motion) always points towards the center of the circle.
Circular Motion An object moving in circular motion is inherently accelerating (centripetal acceleration).
"F = mac It must therefore have a net force continually acting on it. We call this net force the Centripetal Force. ! Q
A car rounds a curve while maintaining a constant speed. Is there a net force on the car as it rounds the curve? (Q7-2)
A car rounds a curve while maintaining a constant speed. Is there a net force on the car as it rounds the curve? (Q7-2)
1.
1.
No – its speed is constant
No – its speed is constant
2. Yes
2. Yes
3. It depends on the sharpness of the curve and the speed of the car
3. It depends on the sharpness of the curve and the speed of the car
4. No – its curve isn’t horizontal.
4. No – its curve isn’t horizontal.
1
It’s hearsay… You may have heard that the force that pushes you to the right side of the car when making a left hand turn is called the centrifugal force. This is a myth that must be busted! The centriFugal Force is a Fictitious Force!
2
Centripetal Acceleration: Equation 2 2 " d % " 2(r % $ ' $ ' v 2 # t & # T & 4( 2 r ac = = = = 2 r r r T
Centripetal Acceleration: Period
The centripetal acceleration has to do with the period of the spin. Period (T): the time it takes for one object to complete one full rotation or revolution Remember one full revolution or rotation is either 360o or 2π radians
4" 2 r ac = 2 T
!
Centripetal acceleration = 4 x pi squared x the radius divided by the period squared
! Linear/tangential velocity (m/s)
Example:
A child 1.35 m from the center of a merry-go-round is moving with a period of 2 minutes. What is her centripetal acceleration in m/sec2?
4" 2 r= 4" (1.35) ac = 2 ) # 60 sec &, T +2 min% (. 2
2
*
!
!
= 0.0037
m s2
$ 1min '-
!
ΣF = m ac
F centripetal = F friction On a day when the roads are icy, the coefficient of friction between a typical tire and the pavement is 0.200. What is the maximum speed a car can make a turn of radius 200.m?
mv 2 = µ mg R v2 = µ g R
v = µ g R = (0.2)(9.8)(200)
v = 19.8 m / s
3
Roads can be banked, to reduce the need for friction to make a turn.
N
Take a cross section of the road…
If a car of mass, m, is going to drive at a linear velocity, v, on a road. At what angle, θ, must the road be banked?
N
N cos θ
X N sin θ
Banked turns
N cos θ
X
θ
N sin θ
θ
"Fy = 0
θ
From the y axis..
!
ΣFy = 0 r r N cos" ! mg = 0
θ
mg
From the x axis..
r r mg N= cos !
& mg # mv 2 $$ cos ' !! sin ' = R % "
r v2 g tan ! = R v2 tan ! = r gR
A girl on a merry-go-round is standing 5 m from the center, and holds a yoyo. If the string makes an angle of 3o with the vertical, how fast is she going?
Note that the banking angle does not depend upon mass.
r
"F
y
Tcos3
v2 tan ! = r gR
mg
r mv 2 N sin ! = R r
T
X
3o
=0
r r T cos # ! mg = 0 r mgr T= cos!
Tsin3 mg
4
A girl on a merry-go-round is standing 5 m from the center, and holds a yoyo. If the string makes an angle of 3o with the vertical, how fast is she going?
r
r
o
! F = T sin 3 x
3o
mv 2 r v2 R g tan 3o = R mv 2 =
r mg sin 3o = cos 3o R
Tsin3
A daredevil drives a motorcycle on a loop-the-loop track. What is the slowest he can go and still make it? (R = 4.0m) 4m
r r v = Rg tan 3o r v = 5(9.8) tan 3o = 1.6 m / s
Remember, that mg is constant, but the normal force varies with the speed.
Of course the tricky part is at the top.
Radius = 4.0 m
"F = ma
c r r mg + N = mac
0
N
mg
N
mg
!
!
r mv 2 mg = R r 2 v = gR
r v = gR = (9.8)(4) = 6.26 m / s
HIDDEN
So why aren’t real loop-theloop tracks circular?
A ball moves at a constant speed along a horizontal circle inside a friction-free cone. The weight of the ball is mg. What other significant force(s) act on the ball? What is the direction of the net force on the ball?
N
mg This is the unbalanced force that is the centripetal force.
5
A rider in a amusement park ride finds herself stuck with her back to the carpeted wall. Which diagram correctly shows the forces acting on her?
Lift
1
2
mg
3
4
5
Floor Q
A rider in a amusement park ride finds herself stuck with her back to the carpeted wall. Which diagram correctly shows the forces acting on her?
