Question

Q5 Q19 Choose the correct formula for the displacement d from the rest position of the object attached to the spring at time t.

Answer 1

t=0, d=0 so ans B is wrong

t=0, dd/dt <0 as it is propelled downward so ans C is wrong

ang vel = 2$\pi$ / period

= 2$\pi$ / 4.5

= 4$\pi$ / 9

so D is the correct answer