Waves and sound
Pendulum timer
Time several swings and compare the period with the formula.
T = 2π√(L/g)
Apparatus
- Pendulum
- Metre rule for the length
- Stopwatch
- g = 10 m/s²
Method
- Set the length from the support to the centre of the bob.
- Start the swing and tap the centre button each time the bob passes the mark, going the same way.
- After five taps, divide the time by five.
- Compare that period with 2π√(L/g). Then change the length and repeat.
Keep a real pendulum clear of faces. Small angles only — the formula is not for full circles.
Length
1m
Formula T
1.99s
Swings timed
0/ 5
Your T
—s
Press Start as it passes the dashed centre line. Then tap Centre at the next five passes in the same direction.
A longer pendulum has a longer period. The mass of the bob is not in the formula.
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