7
Holt Physics Chapter 7: Rotational Motion and the Law of Gravity I. Section 7-1: Measuring Rotational Motion
A. When something spins it undergoes “rotational motion”. When something spins around a single point it is called “circular motion”. B. We measure how fast something spins not in m/s (different points on the object are spinning at different velocities) but by measuring the angle described in a given time period. C. Angles can be measured in radians (rad)

1. The radian is the ratio of the arc length (s) to the radius (r) of a circle

(insert fig. 7-1 here)

2. The radian is a “pure number” with no units (the abbreviation “rad” is always used) 3. Conversions:
360o = 2π rad
360o = 6.28 rad
Θ(rad) = π/180o Θ(deg)
Θ(rad) = .0174533 Θ(deg)

(insert fig. 7-3)

D. Angular displacement describes how much an object has rotated relative to a reference line

(insert fig 7-4)

Angular Displacement

ΔΘ = Δs/r
angular displacement = change in arc length/radius

E. Watch your sign! Θ is considered positive when rotating COUNTERclockwise (when viewed from above). Therefore an angle of ½π rad = -1½π rad F. Angular Speed (ω = “omega”) describes the rate of rotation. Average angular speed is measured in radians per second.

Angular Speed

ωavg = ΔΘ/Δt
average angular speed = angular displacement/time

G. Angular Acceleration (α = “alpha”) occurs when angular speed changes. Remember acceleration? a = velocity/time ??

Angular Acceleration

αavg = ω2 – ω1/t2 – t1 = Δω/Δt

average angular acceleration = change in speed/time

H. “All points on a rotating rigid object have the same angular acceleration and angular speed.” P.250 II. Section 7-2: Tangential and...

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Free Fall
Rachel Shea
Physics 131 Lab, QL
Hasbrouck 210
Sept. 21, 2014
Abstract
This experiment measures the study of motion by observing the force of gravity acting solely upon an object, and also measures reaction time. If an object is in free fall, the only force acting upon it is gravity. The object used in this experiment was a golf ball that provided some acceleration when dropped. A sensor positioned underneath a table recorded the golf ball’s pattern of motion,...

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Experiment 7: Relative Density
Laboratory Report
Marella Dela Cruz, Janrho Dellosa, Arran Enriquez,
Alyssa Estrella, Zacharie Fuentes
Department of Math and Physics
College of Science, University of Santo Tomas
España, Manila Philippines
Abstract
The experiment was conducted to show the different methods on how to determine an object’s composition through its density and to determine an object’s density by displacement method and the Archimedes Principle....

...seatbelts, air bags, crumple zones, and etc. are introduced. Safety devices such as seatbelts, air bags, crumple zones and etc are designed to reduce the forces on the body if there is a collision. These safety devices are mostly made based on the physics principle of force and momentum, which is
This relationship says that if momentum is transferred over a longer period of time, the force involved is less. If the force of a collision can be reduced, then the chances that...

...AP Physics Summer Assignment with
Dr. Crymes
Welcome to AP Physics B! It is a college level
physics course that is fun, interesting, and challenging
on a level you’ve not yet experienced. This assignment
will review all of the prerequisite knowledge expected of
you. There are 7 parts to this assignment. By taking the
time to review and understand all parts of this
assignment, you will help yourself acclimate to the rigor
and...

...it is in motion. If the slope of the graph is increasing it means the object is moving away for the motion detector and if it is decreasing the person is moving towards the motion detector and if the slope is 0 the person is at rest
REFERENCE
Physic for engineers and scientist-serway and jewatt
...

...acid in the water bath to a minimum of 70 degrees Celsius or until liquefied.
5. Move the clamp/tube assembly out of the water.
6. Place the thermometer in the lauric acid. Stir gently with the thermometer until the temperature reaches 60 degrees.
7. As soon as the temperature of the lauric acid reaches 60 degrees Celsius, start recording the temperature every 30 seconds. Maintain a constant stirring motion with the thermometer to ensure that the rate of cooling remains...

...(don’t do it), how much work is need to move it along the line?
Potential is defined that it is equal to minus the work done, and it doesn't change if it's an equipotential.
The force and field are at right angles to an equipotential surface.
7) Move the meter closer to the charge at the center of the screen. What is the new electric potential? Turn on plot again
3.9V
8) Remember that electric potential is energy per charge (1 volt = 1 Joule/Coulomb). Is electric...

...Name Jonathan Durichek (RODP) Electric Fields
Go to http://phet.colorado.edu/simulations/sims.php?sim=Electric_Field_Hockey
and click on Run Now.
1. You rub balloons in your hair and then hang them like in the picture below. Explain why you think they move apart and what might affect how far apart they get.
As I rub the balloons in my hair, I am picking up positive charges from my hair, which are electrons. The static charge produced will remain active on the...