Physics Core/AP 1 and 2

Physics Lab

# Physics Lab: Pendulum Motion 1

## Goal: To measure gravitational acceleration near the earth's surface

#### Materials:

• A single object to act as a weight for the pendulum.
• Strong string or nylon fishing line, able to support your weight without breaking.
• Hook on which to tie pendulum; should be fastened to make the pendulum as long as possible (I used the ceiling hook for a hanging plant).
• Stopwatch or watch with second hand.

#### Procedure

1. Determine the mass of your weight.
2. Tie the weight to the end of the string.
3. Tie the string to your hook.
4. Measure as accurately as possible the distance between the hook and the center of the masses; this is your pendulum length L.
5. Displace the pendulum (measure the horizontal distance x of the displacement of the pendulum from its rest position.)
6. Measure the length of time required for the pendulum to make 10 complete back-and-forth swings (10 periods). Determine the value of T.
7. Repeat at least twice.

#### Data Handling

1. Average your values for T.
2. Using the average value, determine the acceleration due to gravity for your test mass. [As we see in chapter 11, the formula for the period of a pendulum is T = 2π √(L/g).]