The amplitude of a particle executing SHM about `O` is `10 cm`. Then

Options

A. when the `KE` is `0.64` times of its maximum`KE`, its displacement is `6cm` from `O`
B. its speed is half the maximum speed when its displacement is half the maximum displacement
C. Both (a) and (b) are correct
D. Both (a) and (b) are wrong

Answer

A

Explanation

(a) Kinetic energy is `0.64` times, it means speed is `0.8` times
`0.8 omega A = omega sqrt(A^(2)) - (x^(2))`
`:. x = 0.6 A = 6cm`
(b) `(omegaA) /(2) = omega sqrt(A^(2) - x^(2))`
`:. x = sqrt(3)/(2) A`