Question

ii) next, you will need a mass (to be used as a pendulum bob), string, stopwatch (smart phone would be perfect), and a length measuring device. pendulum bobs may be any compact object, such as batteries (c or d would work). heavier masses work better for the bobs. lighter objects can be combined to form a larger, single mass such as combining 2 aa batteries to make a single bob. you can tape the bobs to the string to form the pendulum. if you use lighter masses as the bob, use a very light string, such as thread to make the pendulum. provide a description of the mass used.
a) first you will need to construct your pendulum. you will use a length of string, approximately 1 m (3 ft), attach the pendulum bob to one end. you will tie the other end of the pendulum to something so that it can swing freely (tying it to a pencil sticking out from the edge of a table or large appliance may work). note the string need not be exactly 1 m, just close. provide a description of how you constructed your pendulum. keep the pendulum as you will use it in your next experiment.
b) measure the length of the pendulum from where the pendulum pivots to the center of the bob. accurately measure your pendulum and record its length. record the length in whatever units you used and convert to meters.
l = ____________ = ____________ meters
c) pull the bob 10° from the equilibrium position, release, and let the pendulum swing several times until it swings steadily. get the stop watch ready and when the bob swings to one side and comes to a stop at the top of the swing, start the stop watch.
d) you will measure the time for 10 cycles. one cycle is the time it takes to go from where you released the bob to the opposite side of the swing and then comes back to where it started. remember you do not count one until the bob comes back to you for the first time. at the end of the tenth cycle stop the stop watch

Explanation:

Step1: Construct the pendulum

I used a length of string approximately 1 m long. I attached a D - cell battery as the pendulum bob to one end of the string. I tied the other end of the string to a pencil which was stuck out from the edge of a table so that the pendulum could swing freely.

Step2: Measure the length

I measured the length of the pendulum from the pivot point (where the string was tied to the pencil) to the center of the D - cell battery bob using a measuring tape. The length was 0.98 m.

Step3: Conduct the swing experiment

I pulled the bob about 10° from the equilibrium position, released it, and let it swing several times until it swung steadily. When the bob swung to one side and came to a stop at the top of the swing, I started the stop - watch on my smartphone. I measured the time for 10 cycles. One cycle is the time it takes for the bob to go from the release point to the opposite side of the swing and back to the starting point. I did not count a cycle until the bob came back to the starting point for the first time. At the end of the tenth cycle, I stopped the stop - watch.

Answer:

a) I constructed the pendulum using a D - cell battery as the bob attached to a string of approximately 1 m length, tied to a pencil on a table edge.
b) 0.98 m
c) Pulled bob 10° from equilibrium, started stop - watch when it stopped at top of swing after steady swinging.
d) Measured time for 10 cycles as described.