Creative work

Our last experiment in physics 101.1 is an experiment designed by our own. We designed an experiment on conservation of energy. By using the set up below, we can verify that indeed the energy is conserved throughout the path of the ball. Energies included here are rotational and translational kinetic energy and potential energy.

The following data are obtained from the set up:

x1	x2	x3	<x>	sqrth	<x>
40.5	40.9	41.1	40.83333	5.932959	40.83333
36.7	36.9	36.4	36.66667	5.403702	36.66667
33.8	33.7	34.2	33.9	4.959839	33.9
29.9	30	30.3	30.06667	4.516636	30.06667
26	25.9	26.1	26	4.09878	26
20.9	20.7	21	20.86667	3.405877	20.86667
13.1	14	12.5	13.2	2.539685	13.2

And the graph obtained by plotting the distance versus the square of the height.

We can see that the fit of this graph is nearly linear as predicted by the equation of conservation of momentum where, the change in total mechanical energy is constant since friction does not do any work on the system.

Activity 7

Last week we did experiments on simple harmonic motion. We did experiments on a simple pendulum, a physical pendulum and a spring and mass system. All of these tree follows the equations for the simple harmonic motion: Simple harmonic motion is the simplest kind of oscillation. That is when the restoring force is directly proportional to the displacement from the equilibrium. Most oscillations that we observe are not just as simple as  simple harmonic motion but we can do approximate it as one. The picture on the right represents the setup.

By timing the period or the time it takes for one oscillation to occur, we can get some of the physical properties of the object like the moment of inertia of a physical pendulum. Errors in the data obtain may be caused by the large amplitude. Simple harmonic motion is only true for these cases for small amplitude oscillations. Here are the data obtained:

Simple Pendulum
Trial	Period		Length of string
1	0.947		22 cm
2	0.998
3	0.987
4	0.97
5	0.977

Spring and mass system
Trial	Period	mass
1	0.363	1000 g
2	0.356
3	0.377
4	0.353
5	0.361

Physical pendulum
Trial	Period	mass	length
1	0.927	43.3 g	33.9 cm
2	0.936
3	0.946
4	0.92
5	0.94