🌈 Simple Pendulum – Class 9 Mindmap for Easy Learning!

Rainbow Mind Map: Simple Pendulum

1. About Simple Pendulum

A simple pendulum is a small, heavy bob suspended from a fixed support by a light, inextensible string that swings to and fro under gravity.

2. Time Period (T)

• Time taken to complete one full oscillation.
• Unit: seconds (s)

3. Formula

T = 2π√(l/g)

• T = Time period
• l = Length of the pendulum
• g = Acceleration due to gravity (≈ 9.8 m/s²)

4. Factors Affecting Time Period

• Length of the pendulum – Directly affects T
• Acceleration due to gravity – Inversely affects T
• Mass of bob – No effect
• Amplitude – No effect (if small)

5. Second Pendulum

• A pendulum whose time period is exactly 2 seconds
• It takes 1 second for a half swing
• Length ≈ 1 meter

6. Graphs

• T² vs l → Straight line graph
• Shows: T² ∝ l
• Used to find acceleration due to gravity (g)

7. Real-Life Applications

• Used in clocks (Pendulum Clocks)
• Studying harmonic motion
• To determine 'g' experimentally

Challenge Time!
If the length of a pendulum is 1 m, what will be its time period?

Share your answer in the comments below – let's learn together!

🔍 Frequently Asked Questions (FAQ)

Q1: What is meant by the "time period" of a pendulum?

The time period (T) is the time it takes for the pendulum to complete one full back-and-forth swing (one oscillation). It's measured in seconds (s).

Q2: Does the weight of the bob affect the time period?

Nope! The mass of the bob doesn’t affect the time period. Only the length of the string and gravity matter.

Q3: What happens if the amplitude is large?

For very small amplitudes, the formula T = 2π√(l/g) holds true. But if the amplitude is large, the motion becomes more complex and the time period increases slightly.

Q4: Can I use a pendulum to calculate gravity?

Yes! By measuring the time period and length, you can rearrange the formula to find the value of g.

Q5: Why is it called a “Second Pendulum”?

Because it takes exactly 2 seconds for one full oscillation — 1 second in each direction. Great for timekeeping!