Centripetal Force Lab Report

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Objective:

The purpose of this experiment is to study the nature of Centripetal force by measuring it acting on a mass undergoing angular motion and centripetal acceleration. In this experiment we will evaluate relationship between Centripetal Force, mass, and velocity. Centripetal force is a force that acts on a body moving in a circular path which is directed toward the center around which the body is moving. The apparatus used for this experiment contains a vertical shaft fit into a bearing with a horizontal cross arm attached to the top of the vertical shaft (see Figure A). On one end of the horizontal cross arm there is a counterweight fixed in place and on the other end there is a mass (m), which is slung from a string and is attached …show more content…

Used a Vernier Calipers and measured the diameter of the vertical shaft and record this value.
Placed the mass on the horizontal shaft. Moved the pin and mass 14 cm from the vertical shaft, and then fixed the pin in place below the mass using the setscrew. The distance was recorded.
Secured the mass to the spring the vertical shaft. Practiced spinning the shaft in order for the mass to travel in a circular path directly above the pin.
Once comfortable, timed how long it took for the mass to complete 25 full rotations for three separate trials. For each trial calculated the angular speed of the cross took the average of the three trials.
Removed the spring from the mass. Measure the centripetal force (Fc) on the mass by attaching it to a Newton’s scale and pulled the mass to the 14 cm mark above the pin. Read and recorded the value.
Repeated steps 2-5 above using the radii of 14.3 cm, 14.6 cm, 14.9 cm, and 15.2cm respectively.

Observations
Mass of Block: m=455.6g±.05g
Diameter of Shaft: d=1.13cm±.005cm
Trial r±.05 (m) R=r+½d (m) T25 (Time per 25 Cycles) ±.005 (s) T (s) w=2π/T (rad/s) ac …show more content…

Conclusions
Percent error of the slope:
The slope of the line was supposed to be 1/m= 1/.4556=2.19 however the slope that was obtained was .8539.
%error= (theoretical value-measured value)/(accepted value)*100= (2.19-.8539)/2.19*100=61.0% error
The value that was obtained through the lab was much larger than the value of the slope that it was supposed to be.
There is a lot of human error that is not accounted for in this experiment as when the object is rotating the start time and end time must be manually started and stopped. Due to this the reaction time to start and stop may have been to slow or it may have been started or stopped too early. Furthermore for this experiment when the object is spinning the tangential velocity of the object may be changing because of the frictional force caused by the air and the friction of the shaft rotating on its axle. When the speed is reduced a little more force may be added causing overall variation on the velocity of the object thus affecting the time the object takes to do a revolution. Lastly when getting the object to begin the rotation, the alignment of the rotation of the object to the pin may have been

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