Q.

Time period of a particle executing SHM is 16 s. At time t=2s, it crosses the mean position its amplitude of motion is 322πm. Its velocity at t=4s is

1 1 ms-1  
2 2 ms-1  
3 4 ms-1  
4 8 ms-1  

Ans.

(3)

For SHM,  x=Asinωt=Asin(2πtT),    v=ωA2-x2

When t=4 s, time taken by the particle to travel from the mean position to the given position=4-2=2 s

x=Asin(2πtT)=Asin(2π×216)=A2

v=ωA2-x2

v=ωA2-A22=ωA2

ω=2πT=2π16=π8

∴  v=πA82