# Florida Atlantic University – PHY 2048LExperiment 9 Lab Report: PHY2048L 007 Experiment 9: Buoyant Force

### Florida Atlantic University – PHY 2048LExperiment 9 Lab Report: PHY2048L 007 Experiment 9: Buoyant Force

Florida Atlantic University – PHY 2048LExperiment 9 Lab Report: PHY2048L 007 Experiment 9: Buoyant Force

Lab Report: Experiment 8.2 Moment of inertia Purpose Measure the moments of inertia of rigid bodies: disk, ring and sphere Compare the measured and the calculated moments of inertia to determine the c values of the moments of inertia of the rigid bodies Theory The theory behind this lab is to find the moment of inertia (I) of a rigid body experimentally,

In that matter, a know torque (T) is applied to the object and the resulting angular acceleration (a) is measure, then I=T/a, while the magnitude of a torque is given by T=|r x F|=rFsinΘ, where F is the applied force, r is the position vector of the acting point of the force measured from the rotating axis, Θ is the angle between r and F.

The torque is maximum when Θ = 90. In this experiment, the applied force is the tension (T) in a thread. One end of the thread is tied to a step pulley, which is a part of the rotational apparatus and the other end to a hanger. R is the radius of the step pulley and perpendicular to the applied force T. Therefore T = rT Applying Newton’s second Law for the hanging mass, m, results in: ma = mg – T  T = m(g – a); therefore, Torque= r m(g-a), where a is the linear acceleration of the hanging mass and equal to the tangential acceleration aT, of the rotating apparatus.

The angular acceleration is related to the tangential acceleration α= a_T/r-→ α= a_T+rα Therefore, the moment of inertia can be calculated by: Questions: This depends on the C value. The lowest speed has the highest C value, while the smallest c value has the highest speed. Therefore, I would expect that the disk arrive Because of the formula I = cMR2, the moment of inertia is directly proportional to the C value. The ring has the largest moment of inertia; therefore, it won’t arrive The largest value of C is the ring, and I wont reach the bottom first.