Question

when the length of a simple pendulum is decrease by 20cm the period changes by 10% find the original length ​

Answer 1

Hi mate

We know that time period of pendulum : T= 2π( √l/√g). Then. T directly proportional to √l. (T1/T2)=√ ( L1/L2). ....(1) according to yr question L2 = L1-0.20 and T2 = T1- 10%T1= 0.09 T1 ,now subsitute these values in equation( 1) then square of it. Now, (1/0.81) =( L1/L1- 0.2) on solving you get L1= 0. 20/0.19

= 1 .053 m. I hope it help you......✌️✌️