uniformcircularmotion

# uniformcircularmotion - U niform Circular Motion James...

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Uniform Circular Motion James Poole ***-**-9001 Physics 211 L Monday 12:20 P.M. Project due Monday March 23, 2009. Abstract: In this lab I used the relationship between force and acceleration in uniform circular motion to determine the mass of an object. To do this I used a circular motion apparatus, a set of weights and weight holders, a stopwatch, a meter stick, a string, a paperclip, and a laboratory balance. I determined the mass to be 335 +/- 27.

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Introduction: A particle, or any mass for that matter, is said to be in uniform circular motion if it travels around a circle or a circular arc at constant (uniform) speed. Although the speed does not vary, the particle (the “bob” in our case) is accelerating because the velocity changes in direction. The following figure shows the relationship between the velocity and acceleration at different times. As you can see, the velocity is always directed tangent to the circle in the direction of motion, while the acceleration is directed radially inward. Therefore, the acceleration is called centripetal acceleration, meaning “center seeking”. 1 The magnitude of the acceleration can be defined as a=v 2 /r (where v is the speed of the particle and r is the radius of the circle.) By Newton’s second law (f=m*a), a force must cause this acceleration. Also, the force must be directed toward the center of the circle. Thus, it is called the centripetal force. A centripetal force accelerates a body by 1 http://cnx.org/content/m13871/latest/
changing the direction of the body’s velocity without changing the body’s speed. 2 From our acceleration and Newton’s second law we can define the centripetal force to be F=m*v 2 /r (m=mass, v=speed, r=radius). Also, the period, or the amount of time it takes a particle to complete one rotation, can be found by diving the number of rotations by total time. From the period, one can determine the angular frequency or angular speed using - ϖ = 2 π /T (T=period). My objective was to determine the mass of an object, or the “bob”; I used the previous equation (F=m*v 2 /r ) to find the mass. I had to manipulate the equation using the period and angular speed in order to accomplish this, and then apply it to a graph. I will later show this manipulation on page Procedure: I was equipped with a circular motion apparatus with a cross arm that could be adjusted to different radii, a set of weights and weight holders, a stopwatch, a meter stick, string, a paperclip, and laboratory balance. My first objective was to determine the theoretical mass (we will

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## This note was uploaded on 09/19/2011 for the course PHYS 212 taught by Professor Tedeschi during the Spring '08 term at South Carolina.

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uniformcircularmotion - U niform Circular Motion James...

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