Given data
*The given 4th harmonic frequency is 31.5 Hz
The fundamental frequency is calculated as

Hence, the fundamental frequency is 7.875 Hz
Answer:
A
Explanation:
this because
gravitational potential energy = mass x height x gravitational field strength
so let's assume mass is 2 kg and gravitational field strength is 10 N /kg
so when height is very low, take it as 3 m
gravitational potential energy= 2 x 3 x 10 = 60 j
but when height is 6m
gravitational potential energy = 2 x 6 x 10 = 120 j
so when the height is the greatest, the gravitational potential energy is the highest
so A is the heighest so it has the highest gravitational potential energy.
hope this helps
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