Wednesday

July 30, 2014

July 30, 2014

Posted by **Connie** on Sunday, December 9, 2012 at 6:21pm.

constant rate of 1/2 ft/sec. At the moment when the top of the ladder is 16 feet above the

ground, the bottom of the ladder is sliding away from the wall (horizontally) at the rate of

2/3 ft/sec. At what rate will the bottom of the ladder be sliding away from the wall when the

top of the ladder is 12 feet above the ground?

- Math -
**Steve**, Sunday, December 9, 2012 at 7:52pmif the ladder base is x feet from the wall and reaches y feet high and the ladder length is a,

x^2+y^2 = a^2

2x dx/dt + 2y dy/dt = 0

we are told that dy/dt = -1/2

so, when y=16,

2x (2/3) + 2(16)(-1/2) = 0

x=12

so, x^2+y^2 = 12^2+16^2 = 20^2

when y=12, x=16, and we have

2(16) dx/dt + 2(12)(-1/2) = 0

dx/dt = 3/8

**Related Questions**

Calculus - 1a. 15 ft ladder is placed against a vertical wall. the bottom of the...

Calculus - A 15 ft ladder is placed against a vertical wall. the bottom of the ...

math - A ladder 10 m long rests on horizontal ground and leans against a ...

Calculus! - A 16 ft. ladder leans against a wall, with the top being 12 ft. from...

CALCULUS - A 25 ft ladder is leaning against a vertical wall. At what rate (with...

Calculus - a 5m ladder rests against a vertical wall. The top of the ladder ...

calculus - : A 20m ladder is placed against a wall. The bottom of the ladder is ...

math - A ladder , 5 meter long , standing on a horizontal floor , leans against ...

Math - A 15 ft ladder leans against a wall. The bottom of the ladder is 3 ft ...

maths - a 4m ladder is leaning against a wall when its base starts to slide ...