PHY 215 Lab 4 - Centripetal Force.docx - Laboratory#4 Centripetal Force Title Page Format(10 pt max Purpose Introduction(10 pt max Experimental

# PHY 215 Lab 4 - Centripetal Force.docx - Laboratory#4...

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Laboratory #4: Centripetal Force Title Page & Format __ (10 pt. max) Purpose & Introduction __ (10 pt. max) Experimental Details __ (10 pt. max) Results and Discussion __ (50 pt. max) Conclusions __ (15 pt. max) References __ (5 pt. max) Total Grade ___ Purpose and Introduction The purpose of this experiment was for students to observe centripetal force through the utilization of the Pasco rotational system. When an object moves at a constant speed, it is said to be in a uniform circular motion and it experiences centripetal acceleration and centripetal force. Centripetal force is a force that acts on a mass moving in a circular path and is directed toward the center around which the mass is moving. (1) *The centripetal force always points toward the center of the circle and continually changes direction as the object moves . The speed v of the rotating object is related to the period and the radius of the circle by: (1) According to Newton’s second law, whenever an object accelerates, there must be a net force to create the acceleration . The second law gives this net force as the product of the object’s mass m , and its acceleration v 2 /r . Newton’s Second Law: = ∑? m * a (2) Experimental Details The equipment needed for this lab are the PASCO super pulley (1), PASCO mass and hanger set (1), and lastly, a stopping watch (1). The PASCO centripetal force apparatus was setup in order to calculate the speed (v) of an object moving in a circle. The mass of the bob was weighed on the electronic mass scale, which came out to be 210g. The side post assembly was set to 16.00 cm. The weight hanger was then attached at the end of the hanging bob. The horizontal strings were leveled by pivoting the pulley. Weights were added until the vertical string was aligned with the vertical indicator. The indicator was aligned with the indicator bracket which was done every time the radius changed. The platform was then rotated until the indicator disk was realigned with the indicator bracket. A digital timer was used to measure the time it took for 15 full rotations which were recorded in Table 1. These steps were repeated when the radius was changed to 17.00cm, 18.00, and lastly, 19.00cm. Centripetal Force Apparatus #: 2 Mass of Bob:_m bob =210g > .210kg Table 1: Measured Load and Measured Time for Fifteen Complete Rotations Radius of Path (cm) Mass of Load (g) Trial #1 (s) Trial #2 (s) Trial #3 (s) Trial #4 (s) Trial #5 (s) 16 47 25.00 24.67 26.09 24.97 23.76 17 68 20.54 20.87 20.99 19.70 19.96 18 87 17.94 18.27 18.20 18.32 18.39 19 100 17.40 17.36 17.33 17.55 17.67 Table 2: Period of Rotation for each Trial  • • • 