Question

When the length of a pendulum is decreased by 20 cm, the period changes by 10%.Find the original length and time period.​

Answer 1

Answer:

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✌️✌️

Explanation:

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