Posted by Amy on Wednesday, November 2, 2011 at 10:27pm.
A 20' ladder leans against a building. The bottom of the ladder is sliding away horizontally at a rate of 2 feet per second. How fast is the top of the ladder sliding down the building when it is 12' above the ground?

Calculus  Steve, Thursday, November 3, 2011 at 4:53pm
If you draw a diagram, let x be the distance of the base of the ladder from the wall, and h the height of the ladder against the wall:
x^2 + h^2 = 400
When h = 12,
x^2 = 400  144 = 256
x = 16
2x dx/dt + 2h dh/dt = 0
32 * 2 + 24 dh/dt = 0
dh/dt = 64/24 = 8/3
Answer This Question
Related Questions
 calculus  a ladder 6 feet long leans against a vertical building. the bottom of...
 Calculus  a 12 foot ladder is leaning against a building. If the bottom of the ...
 Calculus  a 14 foot ladder is leaning against a building. If the bottom of the ...
 Math  Suppose there is a 10 meter ladder leaning against the wall of a building...
 Math  A ladder leans against a vertical wall and the top of the ladder is ...
 Calculas  A 13ft ladder is placed against a verticle wall. Suppose the bottom ...
 Calculus Ab  A 26 foot step ladder is leaned up against a 30 foot building to ...
 Calculus  1a. 15 ft ladder is placed against a vertical wall. the bottom of the...
 Calculus  The top of a 24 foot ladder, leaning against a vertical wall, is ...
 Calculus  A 17 foot ladder is leaning against a wall. The bottom of the ladder ...
More Related Questions