IIT JEE , AIEEE Forum - Physics , Mechanics

stavan110

see figure 3-Q3....
let the distance from point A to point of mass M block(say point is K), be Z.
now construct a perpendicular to the base where the pulleys are affixed....
name the point as R...
let the distance KR be X....
let the distance RA be Y...
In triangle ARK,
X^2 + Y^2 = Z^2;
differentiating with respect to time....
2Z dZ/dt = 0 + 2X dX/dt...
therefore...
dX/dt= Z/X*dZ/dt...this can be written as....
dZ/dt/X/Z (here / stands for "whole divided by" )
or... u/cos

..........

dZ/dt = u and X/Z= cos

.....

plz...rate me if u find my answer useful.....

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