Question

1. When the length of a simple pendulum is decreased by 20 cm, the time period changes by 10%.
Find the original length of a pendulum. (Take g = 9.8 m/s 2 )

Answer 1

Answer:

= 1.053 m

Explanation:

L2 = L1 - 0.20

T2 = T1 - 10%T1

T ∞ √L

T1/T2 =√L1/L2

T1/0.9T1 = √L1/L1-0.2

Squaring both the sides

1/0.81 = L1/L1-0.2

L1-0.2 = 0.81L1

L1-0.81L1  = 0.2

0.19L1 = 0.2

L1 = 0.20/0.19

L1 = 1.053