Question

please tell how to find

Answer 1

Let's call the period of the pendulum T. The pendulum moves from point A to point B in half of a period 12T. It then moves from point B to C in half of half of T, which is 12⋅12T or 14T. So it moves from point A to B then to C in 12T+14 which is equivalent to 34T.

The question says all this is done in 3 seconds. This means

34T=3

T=4  seconds

So, the period was 4 seconds. Period itself is defined as the ratio of the time taken t to the number of oscillations n in that time.

T=tn

Since the number of oscillations n is 3.5 cycles, and the period is 4 seconds, inputting these values;

4=t3.5

t=4×3.5=14 seconds

To convert this to minutes, divide by 60.

t=14/60=0.23 minutes