Which of the following quantities are always negative in a simple harmonic motion?
For the motion to be simple Harmonic, Force must be linearly proportional to the displacement.
(a). = Cosθ
Direction of Force and acceleration is always same. Therefore, it will always be positive.
Direction of Velocity and displacement is always same; thus it is also coming positive.
Force is opposite to displacement.
Dot product will become negative as for >90° ,is negative
So, this expression is negative
Force is opposite to displacement so it will also be negative.
Therefore, Option (c). and (d) are correct.