Question

A big pendulum goes back and forth
once every 18.9 s. What is the
length of the pendulum?
(Unit = m)

Answer 1

T = 2π√(L/g)

For earth , g ~ 10

18.9 = 2×3.14 √(L/g)

9 = L/g

L = 90 metres

Answer 2

Answer:

88m

Explanation:

T=2π*$\sqrt{L/g}$-->Τ/2π=$\sqrt{L/g}$-->18.9/2π=$\sqrt{L/g}$-->3=$\sqrt{L/g}$-->3^2=L/g-->9=L/9.8

so L=9*9.8-->L≈88m