Wednesday

September 3, 2014

September 3, 2014

Posted by **Jeff** on Monday, October 26, 2009 at 3:22am.

- calculus -
**Reiny**, Monday, October 26, 2009 at 8:15amAt a time of t seconds,

let the height of the flag be h feet, then the distance to the top of the pole is 40-h feet and length of rope from the top of the pole to the car is 80+h feet.

let the car be x feet from the base of the pole.

given: dx/dt = 3 ft/s

fing: dh/dt , when h = 20

I see Pythagoras here,

x^2 + 40^2 = (80+h)^2

2xdx/dt = 2(80+h)dh/dt

dh/dt = xdx/dt/(80+h)

when h = 20

x^2 + 1600 = 10000

x = 8400

x = √8400

finally

dh/dt = √8400(3)/100

= 2.47 feet/second

**Answer this Question**

**Related Questions**

another math - At a distance of 34 feet from the base of a flag pole, the angle ...

Math - At a distance of 56 feet from the base of a flag pole, the angle of ...

geometry - A wire is attached to the top of a flag pole. The wire meets the ...

math - A 5-foot tall women is standing near a flag pole which casts a shadow of ...

Thinking Mathematically - solve A Flag Pole Has A Height Of 16 Yards. It Will Be...

physcis - a flag pole is 1ooft from an observer who sights the top of the flag ...

business math - a 4 foot post that is 8 feet from a flag pole is casting a ...

Grade 11 Math - From a window in apartment building the angle of evaluation from...

word problem - A 62 foot rope hangs from the top of a pole. When pulled taut to ...

Calculus - A boat is pulled into a dock by means of a rope attached to a pulley ...