A conical pendulum consists of a mass `M` suspended from a string of length `l`. The mass executes a circle of radius `R` in a horizontal plane with speed `v`. At time `t`, the mass is at position `Rhat i` and has velocity `v hat j`. At time `t`, the angular momentum vector of the mass `M` about the point from which the string suspended is

Options

A. `M upsilonRhatk`
B. `m upsilonlhatk`
C. `M upsilonl[(sqrt(l^(2)-R^(2))/lhati)+R/lhatk]`
D. `-M upsilonl[(sqrt(l^(2)-R^(2))/lhati)+R/lhatk]`

Answer

C

Explanation

`vec(r)=Rhati-sqrt(l^(2)-R^(2)hatk)`
`vec(P)=Mupsilonhatj`
`vec(L)=vec(r)xxvec(P)`