Physics 101L
CENTRIPETAL FORCE- Report
A. Vary Radius (Constant Force and Mass)
The weight of the mass hanging over the pulley is equal to the centripetal force applied
by the spring.
Mass of the object:
m =___ __________________
Mass Hanging over the pulley: 𝑀 =____ __________________
Radius (cm)
𝑇2
Period 𝑇 (s)
Table A-1: Varying the Radius
a. On a graph paper, plot the radius versus the square of the period. Prove that the graph is
a straight line.
b. Draw the best-fit line through the data points.
c. Determine the slope of the line along with its error. Record this slope in table A-2.
c. Deduce the centripetal force along with its error and record it in table A-2.
d. Compare the two values found for the centripetal force.

Slope from graph:
Centripetal force = 𝑀g

Centripetal force from slope

Table A-2: Varying the Radius
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B. Varying the centripetal force
The weight of the mass hanging over the pulley is equal to the centripetal force applied
by the spring. Calculate this force for each trial and record the result in Table B-1.
Mass of the object:
____________________
Radius:
___________________
Slope from Graph:
____________________
Mass over pulley (g) Centripetal Force = 𝑀g
1
𝑇2
Period 𝑇 (s)
Table B-1: Varying the Centripetal Force
a. Calculate the inverse of the square of the period for each trial and record it in
table B-1.
b. On a graph paper, plot the centripetal force versus the inverse square of the period. Prove
that the obtained plot is a straight line.
c. Draw the best-fit line through the data points and measure the slope of the line. Record
the slope in Table B-1.
d. Calculate the mass of the object from the slope along with its error and record it in table
B-2.
e. Compare the two values found for the mass of the object.
Mass of the object (measured using balance)


Mass of the object (From slope)
Table II-1: Varying the Centripetal Force
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C. Vary Mass (Constant Force and Radius)
The weight of the mass hanging over the pulley is equal to the centripetal force applied
by the spring. Calculate this force for each trial and record the result in Table C.
Mass hanging over pulley:
Centripetal Force = 𝑀g:
Radius:
Mass of Object (g)
_______________________
__________________________
_______________________
Period 𝑇 (s)
Calculated centripetal Force % Difference
Table C: Varying the Mass
a. Calculate the centripetal force for each trial using:
𝐹=
4𝜋 2 𝑚𝑟
𝑇2
and record it in Table C.
b. Calculate the percentage difference between the calculated centripetal force for each trial
and 𝑚g. Record the result in Table C.
Questions:
1. Does increasing the radius cause an increase or decrease in the period of rotation?
2. When the radius and the mass of the rotating object are held constant, does
increasing the period cause an increase or decrease in the centripetal force?
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3. Does increasing the mass of the object cause an increase or decrease in the
centripetal force?
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