Pendulum A with mass m and length l has a period of T. If pendulum B has a mass of 2m and a length of 2l, how does the period of pendulum B compare to the period of pendulum A?

Question

A. The period of pendulum B is 2 times that of pendulum A.
B. The period of pendulum B is half of that of pendulum A.
C. The period of pendulum B is 1.4 times that of pendulum A.
D. The period of pendulum B is 0.71 times that of pendulum A.
E. The period of pendulum B is the same as that of pendulum A.

Answer 1

T^2 is proportional to L/g. The mass has no effect.

So, if A^2 = L/g
B^2 = 2L/g

B^2/A^2 = 2
B/A = √2 ≈ 1.4
answer C

Answer 2

Good Question