Thursday

August 21, 2014

August 21, 2014

Posted by **AH** on Friday, November 2, 2012 at 1:07pm.

- Math -
**Reiny**, Friday, November 2, 2012 at 5:16pmLet the time passes since the woman started walking be t seconds

So the an has walked for t+300 seconds, let his position be A on a NS-EW grid

let the woman's position after t seconds be B

Draw AB, the distance between them.

Complete a right-angled triangle by extending AP downwards to a point C, so that PC is the woman's distance and CB= 500

AP = 5(t+300) = 5t + 1500

PC = 4t

AC = 9t+1500

AB^2 = (9t+1500)^2 + 500^2

when t = 15 min = 900 sec

2AB d(AB)/dt = 2(9t+1500)(9) + 0

d(AB)/dt = 9(9t+1500)/AB

so when t=15 min = 900sec

AB^2 = 92160000 + 250000

AB = 9613.01 ft

d(AB)/dt = 9(9600)/9613.01

= 8.99 ft/sec

- Math -
**AH**, Saturday, November 3, 2012 at 12:50amThank you very much!

**Related Questions**

calculus - A man starts walking north at 4ft/s from a point P. Five minutes ...

calculus - A man starts walking north at 3ft/s from a point P. Five minutes ...

calculus - A man starts walking north at 2ft/s from a point P. Twenty-five ...

Calculus - A man starts walking north at 4 ft/sec from point P. Five minutes ...

Calculus 1 - Francis starts walking north at 4 ft/s from an intersection I. At ...

maths - After walking due west,turning and walking due south a man is 900 metres...

Math Calculus - Hi, can anyone please help me solving these problems? any help ...

Math - a boat starts at point A, moves 3km due north, then 2 km due east, then 1...

Physics - A man at point A directs his rowboat due north toward point B, ...

math - A boat starts at point A, moves 3 km due north, then 2 km due east, then ...