PASCO ME-8950A COMPLETE ROTATIONAL SYSTEM - Manual (Page 18)

Complete Rotational System 012-05293F
14
Measure the Radius
1. Using calipers, measure the diameter of the step pulley about which the thread is wrapped and
calculate the radius.
2. Record the radius in Table 1.4.
Analysis
1. Calculate the average of the angular speeds in Table 1.3 and record the result in Table 1.5.
2. Calculate the rotational inertia:
•
Subtract the “friction mass” from the hanging mass used to accelerate the apparatus to determine
the mass, m, to be used in the equations.
• Calculate the experimental value of the rotational inertia and record it in Table 1.5.
3. Using the average angular speed, the rotational inertia, and the distance, r, calculate the muzzle
velocity of the ball and record it in Table 1.5.
4. Calculate the percent difference between the muzzle velocities found in Parts I and II. Record in
Table 1.5.
Questions
1. What percentage of the kinetic energy is lost in the collision? Use the masses and velocities to
calculate this percentage.
%Lost
KE
before
KE
after
–
KE
before
----------------------------------------------x100% =
Average Angular Speed
Rotational Inertia
Calculated Initial Velocity, v
0
Measured Initial Velocity
% Difference
Table 1.5 Results