Question

Take a ping pong ball and tie it with a string of length 98 cm. Suspend it from a point such that it can swing. Swing the ball. Find the time for 20 oscillations, 40 oscillations and 60 oscillations. Hence calculate the time period in each case. What inference can you draw from your observations ? Support your answer.

Answer 1

Explanation ⇒

Let us first calculate the time period of the pendulum,

Using the formula,

  $T = 2\pi \sqrt{\frac{l}{g}}$

T = 2 × 22/7 × √(98/980)

∴ T = 44/7 × 1/√10

∴ T = 1.99 seconds ≈ 2 seconds.

It is the time taken by the ping ball to complete one oscillations.

∴ Time required by the pendulum to complete the 20 oscillations = 2 × 20 = 40 seconds.

∴ Time required by the pendulum to complete the 40 oscillations = 2 × 40 = 80 seconds.

∴ Time required by the pendulum to complete the 60 oscillations = 2 × 60 = 120 seconds.

Now, The reference which we can draw is that time period is just double of the no. of oscillation. This means, in oscillations, time taken is 2 seconds.

Hope it helps.

Answer 2

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