Which of the following quantities are always positive in a simple harmonic motion?

In a simple Harmonic motion, Force must be linearly proportional to the displacement.


Also, F = -kx


a = -ω2x



(a).


Direction of Force and acceleration is always same. So, the


dot product will become positive as for <90° ,is positive.


So this expression is positive.


(b).


Direction of velocity and displacement is same so the expression will also be positive.


(c).


Force is opposite to displacement.


Dot product will become negative as for >90° ,is negative


So, this expression is negative


Again,


(d)


Force is opposite to displacement so it will also be negative.


Therefore, the option a and b are correct.

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