**"g" by Pendulum**

Objective: Measure "g" using the period (T) of a pendulum.

**Equipment:** pendulum, pressure
clamps, meter stick, stopwatch, vernier caliper

**Methods:**

1. Sketch and label the set up.

2. Determine the length (L) of
the pendulum to the *center* of the ball (string + 2 diameter of ball).

3. Swing the pendulum with an arc
**<**10^{o}
from the vertical. Countdown “3-2-1-0”
before starting the stopwatch

4. Record the total time for 50
complete swings.

5. Repeat for 5 other lengths of
the pendulum between 0.2 m and 2 m.

**Analysis:**

1. Calculate the period (T) for *one*
swing to the nearest 0.01 second for
each pendulum length, then T^{2}.

2. Plot the data of L vs T^{2}
(L on the y-axis). Calculate the slope
with units. What does the slope represent? Calculate g *using your slope* and the
equation derived in class.

3. Calculate a percent error
using 9.804m/s^{2} for Brockport.

4. Using your graph,
predict L by interpolation when T = 1.0s; 2.0s (remember: your x-axis is T^{2}).

5. Why did we use 50 swings to
determine T rather than 1or 2 swings?

6. How would a 1 second period (T)
on earth be different for your pendulum on the moon? (g_{m} = 1.67 m/s^{2}).

7. What length pendulum on
the moon would produce a 2.0 s clock?

8. Grandfather clocks have a 2.0
second swing. If a 3.0 second clock
(great grandfather) could be made, how tall would a room have to be?

9. How would a pendulum bob of different
mass affect your results?

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