A. Nomenclature
1. Speed – magnitude of an objects rate of motion (no direction, scalar quantity) 2. Velocity – speed and direction of an objects motion (vector, mag & direction) 3. If a car’s speed is constant but direction is changing, velocity is changing. 4. 2 ways to change velocity (change speed or change direction). 5. acceleration – change in speed over time (vector quantity) TWO types; a. Linear acceleration – speed up or slow down

b. Centripetal acceleration – change direction

B. Centripetal acceleration (ac) – acceleration changes due to change in direction.
1. Centripetal means center seeking
2. ac is always directed toward the center of the curved path (circle) 3. If an object is moving in a circle it will always have a centripetal acceleration 4. ac = v2/rv=velocity tangent to the circle (m/s)r = radius of the circle (m)

C. Centripetal Force – the force that causes and maintains circular motion 1. Centripetal Force – Fc – psuedo-force (various forces act as center seeking force) 2. Fc – direction always toward the center.

3. Fc=mac (sub ac = v2/r)
4. Identify Fc
a. Rope over your head
b. Car rounds a corner
c. Earth – Moon
d. Gravitron machine (Fn)
e. Loop de loop (Fn Fg)
f. Swing set ride (Ftx)

D. Practice Problems in workbook p 57then regents practice 8 questions Additional Problems

7) A 13,500 N car traveling at 50.0 km/h rounds a curve of radius 2.00 x 10 2 m. find the following.
a) the ac
b) the fc
c) the minimum coefficient of static friction µ

a) 0.96 m/s2b)1322 Nc) µ=0.09

8) In the gravitron machine a cylinder with a diameter of 6 meters is set in rotation with a tangential velocity of 15 m/s. When the floor drops away, riders are suspended against the wall in a vertical position. Calculate the minimum...

...Exploration Guide: Uniform CircularMotion
Go to www.explorelearning.com and login. Please type or write your answers on a separate sheet of paper, not squished in the spaces on these pages. When relevant, data collected should be presented in a table.
Objective: To explore the acceleration and force of an object that travels a circular path at constant speed. Motion of this kind is called uniform circularmotion.
Part 1: Centripetal Acceleration
1. The Gizmotm shows both a top view and a side view of a puck constrained by a string, traveling a circular path on an air table. Be sure the Gizmo has these settings: radius 8 m, mass 5 kg, and velocity 8 m/s. Then click Play and observe the motion of the puck.
a. The puck in the Gizmo is traveling at a constant speed, but it is NOT traveling at a constant velocity. Explain why.
b. Because the velocity of the puck is changing (because its direction is changing), the puck must be experiencing an acceleration. Click BAR CHART and choose Acceleration from the dropdown menu. Check Show numerical values. The leftmost bar shows the magnitude of the acceleration, or |a|. (The other two bars show the x- and y-components of the acceleration, ax and ay.) What is the value of |a|? Jot this value down, along with radius = 8 m, so that you can refer to it later.
c. Keeping velocity set to 8 m/s, set radius to 4 m....

...CircularMotion and Gravitation
Circularmotion is everywhere, from atoms to galaxies, from flagella to Ferris wheels. Two terms are frequently used to describe such motion. In general, we say that an object rotates when the axis of rotation lies within the body, and that it revolves when the axis is outside it. Thus, the Earth rotates on its axis and revolves about the Sun.
When a body rotates on its axis, all the particles of the body revolve – that is, they move in circular paths about the body’s axis of rotation. For example, the particles that make up a compact disc all travel in circles about the hub of the CD player. In fact, as a “particle” on Earth, you are continually in circularmotion about the Earth’s rotational axis.
Gravity plays a large role in determining the motions of the planets, since it supplies the force necessary to maintain their nearly circular orbits. Newton’s Law of Gravity describes this fundamental force and will analyze the planetary motion in terms of this and other related basic laws. The same considerations will help you understand the motions of Earth satellites, of which there is one natural one and many artificial ones.
Angular Measure
Motion is described as a time rate of change of position. Angular velocity involves a time rate of...

...Uniform CircularMotion – a constant motion along a circle; the unfirom motion of a body along a circle
Frequency (f) – the number of cycles or revolutions completed by the same object in a given time; may be expressed as per second, per minute, per hour, per year, etc.; standard unit is revolutions per second (rev/s)
Period (T) – the time it takes for an object to make one complete revolution; may be expressed in seconds, minutes, hours, years, etc.; standard unit is seconds per revolution (s/rev)
Note: Period and frequency are reciprocals: T = 1/f; f = 1/T.
Sample Problems:
1. Suppose the rear wheel makes 5 revolutions in 1 minute. Find the wheel’s period and frequency.
2. As a bucket of water is tied to a string and spun in a circle, it made 85 revolutions in a minute. Find its period and frequency.
3. * An object orbits in a circularmotion 12.51 times in 10.41 seconds. What is the frequency of this motion?
Tangential Speed (v or vs) – average speed; rotational speed; speed of any particle in uniform circularmotion; standard unit is meters per second (m/s); v = Cf = C/T = 2πrf = 2πr/T = rω
Sample Problems:
3. What is the rotational speed of a person standing at the earth’s equator given that its radius is 6.38*106 m and that it takes 365 days for the earth to complete a revolution?
4. A ball that is whirled about on a...

...
Daily Use of Physics
Jason L. McDuffy
University of Memphis
Physics 1 (online)
Project 1
Daily Use of PhysicsPhysics is considered to be a powerful lens that helps people view the everyday world. Physics is reflected in the everyday phenomena, puzzles and toys that offer a variety of interesting challenges leading to deep and interesting problems that derive from science and mathematics. It provides us an understanding of energy, motion and explains these facts as a combination of fundamental particles interacting through fundamental forces. Hence, it is a study of natural phenomena (Oerter, 2006).
Physics is everywhere around us. It is the backbone for any daily life example including electricity, electric light, wristwatch, CD player, cell phone, radio, plasma TV set, computer, refrigerator, and others. Any technology that is used in our daily life is related to this science. In addition, it is believed that physics is a necessity in solving a number of future problems as all forward-looking developments are based on the insights of physics. These potential problems may be related to the development of fuel cells, nuclear fusion as an energy source, and others.
Once upon a time our eyes were the only way for us to see the world. But increasingly sophisticated instruments developed by...

...The Physics of Carousel
A Research Paper
Presented to
International program-physics
Global Prestasi School
In partial fullfilment
of the Requirements for the IGCSE-Physics
preparatory class
by
Nandira Kirana Thaib
January 2013
TABLE OF CONTENTS
Page
What is a carousel?....................................................................................................... 2
History…………………………………………………………………………………………. 3
ThePhysics of Carousel……………………………………………………………………. 4
Bibliography………………………………………………………………………………….. 6
What is a carousel?
A carousel, or merry-go-round, is an amusement ride consisting of a rotating circular platform with seats for riders. The "seats" are traditionally in the form of rows of wooden horses or other animals mounted on posts, many of which are moved up and down by gearwork to simulate galloping to the accompaniment of looped circus music.
Carousels are commonly populated with horses, each horse weighing roughly 100 lbs (45 kg), but may include diverse varieties of mounts, like pigs, zebras, tigers, or mythological creatures such as dragons or unicorns. Sometimes, chairlike or benchlike seats are used as well, and occasionally mounts can be shaped like airplanes or cars.
History
The carousel is based on a game called “carosella” that was played by Turkish and Arabian soldiers in the 1100s. The game involved soldiers on horseback, riding around in...

...INVESTIGATING CIRCULARMOTION 11/3/04
AIM
To examine some of the factors affecting the motion of an object undergoing uniform circularmotion, and then to determine the quantitative relationship between the variables of force, velocity and radius.
APPARATUS
Rubber bung Metre rule 50 gram slot masses
Glass tube 50-gram mass carrier 50-gram slot masses Metre rule
Stopwatch Sticky tape Metre rule String
THEORY
As in Jacaranda HSC Science Physics 2 p.54
In this experiment when the rubber bung is moving in a circularmotion and the string it is tied to moves neither up or down a constant radius is being maintained. For this to be true the centripetal force must equal the gravitational force hence
Mv"/r = mg from this
v"/r =mg/M and v" ∞ r therefore as v increases so does r and vice versa.
Where
m = Mass of mass carrier + masses (kg)
g = acceleration due to gravity 9.8 m/sec"
M = mass of object in motion (kg)
v = instantaneous velocity of mass (m/sec)
r = radius of circularmotion (m)
METHOD
As in Jacaranda HSC Science Physics 2 p.54
However instead of measuring the time for 10 revolutions, the time for 20 revolutions was measured, this allowed more accurate results to be obtained. Furthermore the lengths given in the book were used as merely guidelines and not followed precisely also 50 and...

...Physics 1 – Mechanics and Heat
Lecture Notes
Prepared by:
ENGR. HAROLD JAN R. TERANO, ECE
Lesson 5
ROTATIONAL KINEMATICS AND DYNAMICS
Uniform CircularMotion – an object moves at a constant speed along a circular path.
Velocity is always tangent to the path in circularmotion. Speed is constant, velocity is not.
Centripetal Acceleration, – acceleration that maintains the object along a circular path directed towards the center. Also called as radial acceleration.
In 1673, Christian Huygens, determined the following relationships.
Velocity,
Where, r = radius of curvature/path, t = time/period.
Frequency (f) – number of revolutions of cycle completed per unit time.
So,
Expressing centripetal acceleration in terms of frequency,
In terms of period,
Example(1)
It takes a merry-go-round moves 30 seconds to complete one revolution, what is the velocity of the child on top of a horse found 3 meters away from the center?
Given:
r = 3 meters
t = 30 seconds
Req’d:
v = ?
Solution:
Example(2)
A micro compact disc (CD) is 6 cm in diameter. If a drive spins uniformly at 300 revolutions per minute, what is the acceleration in m/s2 of a particle of dirt found along the edge?
Given:
d = 6 cm
f = 300 rev/min.
Req’d:
ac = ?
Solution:
Centripetal and...

...change and the speed (i.e. the magnitude of the velocity) will remain constant.
If a ball is attached to the end of string and swung at a constant speed (i.e. only the direction of the velocity is changing not the magnitude) then there must still be an acceleration. The acceleration is directed towards the center of the motion. This acceleration is call centripetal acceleration!
2.6.2 State the expression for centripetal acceleration.
The acceleration of any object moving in a circle at a constant speed is given by the equation:
(1)
a⃗ =v2r
It is important to note that centripetal acceleration is very special. It is the acceleration required for an object to move in a circle at a constant speed.
The reverse is also true if an object's acceleration is equal to v2r (and perpendicular to the velocity) then the object must be going in a circle.
If an object is moving in a circle at with a changing velocity, then the overall acceleration is not equation to the centripetal acceleration. However the acceleration perpendicular to the velocity (that is the part changing the direction) is still equal to v2r
2.6.3 Identify the force producing circularmotion in various situations
Sometimes people will make reference to the "centripetal force." This is not a real force, its a pseudo-force. In general the centripetal force is made up of many other forces and is the sum of those forces. This is not unlike the idea of a net force...