The ladder is placed against the wall with its upper end touching the wall. The ladder bottom rests on the ground and is 10ft away from the wall and also makes an angle 60° with the ground. After some time, ladder begins to slip and the angle of contact changes to 30° in a minute. Find the rate of slip in ft/sec?
1
0.85
2
0.63
3
0.12
4
0.26