Inertial Balance

This experiment was conducted with the intentions of showing that the measuring of inertia is separate from gravitational forces, as well as, to use inertia to measure the mass of the given objects. This lab was also to insure that the inertia mass of the objects is the same as the gravitational masses. IN this lab we will answer the question “what is the unknown mass?”Inertia is the resistance to change in its state of motion; an example could be a moving car. There are a couple of different ways of measuring mass, such as the triple beam balance. Although it is quick and pretty simple it has its drawbacks, one being that it is hard to understand how the answer you receive relates to the definition of mass. Triple beam balances also will not work if there is no gravity present. We use the mass of the object to identify the efforts of an object to change velocity. The inertia balance uses two strips of spring steel to vibrate the object back and forth. When the scale vibrates quickly that the mass of the object will be less compared to when is takes slower wider vibrations. Inertial balance is capable of being use in weightless situations, such as in space flights. I believe that after calculating all the known masses, we will be able to determine the unknown mass and be within 10 grams of the actual mass. This experiment required several materials, a C-clamp, inertial balance, a mass set, a stopwatch, and some duct tape. For this experiment we began as usual, we gathered the materials need on a lab table in the back of the room. With the teachers help we used the C-clamp to grasp the inertia balance to the edge of the table (as shown in figure 1). After it is secure, place a small piece of duct tape on the balance pan, make sure it is sticking to the balance as well as up to stick to the weights. You can start with 0 grams but we started with 20 grams, and worked our way up to around 200 grams, more could cause the scale to buckle. Change weight by approximately 20 grams after each trail for sufficient results. Using one finger, we pulled the balance pan to either the left or right and let go. Once the scale beings vibrating have one person start the stopwatch and that same person counts 20 oscillations. After 20 oscillations that individual will stop the stopwatch. Record the amount of time (seconds) that it took, and repeat 3 times for every weight. Once (Figure 1) you have your three trails take the average time for each weight, and find the time for one oscillation (time for 20 oscillations/ 20). Then, create a graph with you known masses and the time for one oscillation, including line of best fit. Your teacher will then give you an unknown mass. Follow the same instructions. Take the time for the unknowns one oscillation and place it on your graph. Then use a triple beam balance to find the actual weight and calculate the percent error. Mass (grams)
Trial 1 (sec)
Trial 2 (sec)
Trial 3 (sec)
Average (sec)
Period of one oscillation (seconds)
20
7.1
7.2
7.1
7.1
0.355
50
8.7
8.4
9.1
8.7
0.436
70
9.3
8.7
9.7
9.2
0.46
100
9.5
9.6
9.6
9.6
0.48
200
12
12.4
12
12.2
0.61
Unknown
14
14
14
14
0.7

By our calculations, before the triple beam balance, the unknown weight about 260 grams. Although, we then weighted it and realized that the actual is 294.3 grams with a 13.2% error. Even though our calculations were a little off, our procedures were correct. Before we started the experiment I didn’t understand how we could use inertia to calculate the inertial mass of an object. Now I see how the mass of an object slows down the scale because it is resisting more than an object with a smaller mass would. Our inertial balance was old and falling apart, so if we had newer ones they would be able to hold higher masses. Which would allow us to explore inertial masses of larger objects. Another cool experiment would be to take an inertial balance into space on the space shuttle and to do several testes up