Answer:

Explanation:
As we know that there is no external torque on the system of platform, banana and the monkey
so the angular momentum of the system will remains conserved
so here we can say


here we know that





Now from above equation



The frequency of the wave is 
Explanation:
The frequency, the wavelength and the speed of a wave are related by the following equation:

where
c is the speed of the wave
f is the frequency
is the wavelength
For the radio wave in this problem,


Therefore, the frequency is:

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Answer:
Vernier calipers is used to measure the internal diameter of a beaker