Question

Which of the following quantities are always negative in a SHM?​

Answer 1

Answer:

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

Alos, F = -kx

a = -ω²x

v = ± ω√(A² - x²)

(a). F.a = |F||a|Cosθ

Direction of Force and acceleration is always same. Therefore, it will always be positive.

(b). v.r = |v||r|cosθ

Direction of Velocity and displacement is always same, thus it is also not the answer.

(c). and (d).  Direction of Force and acceleration is always opposite to Displacement.

∴ Dot product of Displacement with Force and displacement with acceleration will always be negative.

Hence, Option (c). and (d) are correct.

Hope it helps.