sir according to this theory answer should be option 2 but why answer is option1

Asked by ritibhrajvvrs3247 | 15th Sep, 2021, 10:27: PM

Expert Answer:

The theory you have shown in the figure is for modulus of difference between kinetic energy K
and potential energy U , i.e., | K - U |
Whereas  given question is related to actual difference between kinetic energy K and
potenial energy U , i.e., ( K - U )
Let us assume the mass oscillating SHM motion starts from equilibrium position at t = 0 . 
At t=0 , Kinetic energy is maximum and potential energy is zero , hence (K-U) is maximum positive.
When the mass reaches the amplitude position at t = T/4 , where T is period of SHM ,
kinetic energy is zero but potenital energy is maximum.
Hence we get (K-U) is maximum negative . When the mass again goes back to equilibrium position
at time t = T/2 , we get ( K-U) is maximum positive.
Hence time period of full cycle for (K-U) is T/2 .
Hence for given question , time period of SHM T = 4 s and time period of (K-U) = T/2 = 4/2 = 2 s

Answered by Thiyagarajan K | 16th Sep, 2021, 12:33: AM

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