Splung.com Physics Forum

[pnwokolo]

A solid disk of unknown mass ad known radius R is used as a pulley in a lab experiment,
as shown. A small block of mass m is attached to a string, the other end of
which is attached to the pulley and wrapped around it several times. The block of
mass m is released from rest and takes a time t to fall the distance D to the floor.



(a) Calculate the linear acceleration a of the falling block in terms of the given
quantities.
(b) The time t is measured for various heights D and the data are recorded in the
following table.
D(m) t(s)
0.5 0.68
1 1.02
1.5 1.19
2 1.38
i. What quantities should be graphed in order to best determine the acceleration
of the block? Explain your reasoning.
ii. On a sheet of graph paper (or using a graphing utility), plot the quantities
determined in (b), label the axes, and draw the best fit line to the data.
iii. Use your graph to calculate the magnitude of the acceleration.
(c) Calculate the rotational inertial of the pulley in terms of m, R, a, and fundamental
constants (g, etc.).
(d) The value of the acceleration found in (b)iii, along with numerical values for the
given quantities and your answer to (c) can be used to determine the rotational
inertia of the pulley. The pulley is removed from its support and its rotational
inertia is found to be greater than this value. Give one explanation for this
discrepancy.

[hepcj]

See the post above.