(II) A mass at the end of a spring vibrates with a frequency of . When an additional 680 -g mass is added to , the frequency is . What is the value of

Solution 8Q

A tyre swing hangs from a branch close to the ground.

We need to estimate the height of the branch using only a stop watch.

The tyre is pulled to one side and then let go. This will act like a pendulum.

The time taken for 10 to and fro motions is noted.

From this the time for 1 oscillation is calculated.

We know that

Where T is the time period, h is the length of the pendulum, which in this case is the height of the tree.

Knowing all other quantities, the value of h can be calculated