Question

Take a hollow plastic ball (dia 3cm to 5cm) using a needle. Pass a thread of about 105 cm along a diameter of the ball.Tie a knot at one end. Hang the ball from a rigid support so that the ball is free to oscillate.Make a small hole (5mm dia) in the ball near the top.Fill it with sand and find its time period of oscillation. Empty the ball and fill it with steel balls/iron filings and repeat the experiment.Similarly carry out the experiment with common salt.compare the time periods obtained in the above three cases.What do you find? Explain your finding.