A conveyor belt moves to the right with speed `upsilon = 300 m//s`. A very fast pieman puts pies on the belt at a rate of `20` per minute and they are recived at the other end by a pieeater.
(a) If the pieman is stationary find the spacing `x` betweenthe pies and the frequency with which they are recived by the stationary pieeater.
(b) the pieman now walks with speed `30 n//min` towards the reciver while continuing to put pies on the recived by the stationary pieeater.

Answer

A, B, C

Explanation

This problem is a Doppler's effect analogy.
(a) Here, `f = 20 min^(-1)`
`nu = 300 m//min`
`nu_(s) = 0` and `nu_(0) = 0`
Spacing between the pipe` = (300)/(20) = 15 m`
and `f' = f = 20 min^(-1)`
(b) `nu_(s) = 30 m//min`
Spacing between the pies will be
`= (300 - 30)/(20)` or `13.5 m`
and `f' = f ((nu)/(nu - nu_(s))) = (20) ((300)/(300 - 30))`
`= 22.22 min^(-1)`