Thursday
February 26, 2015

Homework Help: Calculus

Posted by saud on Saturday, October 29, 2011 at 10:10pm.

A 15 ft ladder leans against a wall. The bottom of the ladder is 4 ft from the wall at time t=0 and slides away from the wall at a rate of 3ft/sec.

Find the velocity of the top of the ladder at time t=2.

The velocity of ladder at time t=2 is ........ft/sec.
• Calculus - Reiny, Sunday, October 30, 2011 at 12:03am

let foot of ladder be x ft from wall
let top of ladder by y ft above grouns
x^2 + y^2 = 15^2
2x dx/dt + 2y dy/dt = 0

so when t = 2, x = 4+6 = 10
y^2 = 225-100 = 125
y = √125 , and dx/dt = 3

2(10)(3) + 2(√125 dy/dt = 0
dy/dt = -60/(2√125)
= -30/√125
= appr. -.2.68 ft/sec

• ap wizardry - Maroneys School of wizardry, Monday, January 7, 2013 at 1:10pm

according to the ap wizardry handbook, using the demon spawn spell, the problem can be obliterated thorugh fire spitting dragons that originiate from the vave of JF.

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