# Separate multiple an swers by commas f has relative

• Homework Help
• zhrngx68
• 5
• 100% (1) 1 out of 1 people found this document helpful

This preview shows page 3 - 5 out of 5 pages.

(Separate multiple an-swers by commas.)f0has relative minima at:(Separate multiple an-swers by commas.)
16.(1 point)Two light sources of identical strength are placed 10 m apart.An object is to be placed at a point P on a line l parallel to theline joining the light sources and at a distance d meters from it(see the figure). We want to locate P on l so that the intensityof illumination is minimized. We need to use the fact that theintensity of illumination for a single source is directly propor-tional to the strength of the source and inversely proportional tothe square of the distance from the source.3
(a) Find an expression for the intensity I(x) at the point P.(Your answer may depend on x,d, and k where k is the productof the proportionality constant and the strength of the sources).
(c) If d = 10 m find the smallest value of x which minimizesthe intensity.
(d) Somewhere between d = 5 m and d = 10 m there is a tran-sitional value of d at which the point of minimal illuminationabruptly changes. Find this value for d.d =m
17.(1 point) A woman at a pointAon the shore of a circularlake with radiusr=2 wants to arrive at the pointCdiametricallyoppositeAon the other side of the lake in the shortest possibletime. She can walk at the rate of 8mph and row a boat at 4mph.What is the shortest amount of time it would take her to reachpointC?