If the string is inextensible, determine the velocity u of each block in terms of v and `theta`.

(a) fig a: u=…
(b) fig.(b): u=….

Explanation

(a) Length of the string: `l=x+2sqrt(h^(2)+y^(2))`
Differentiating, we get `(dl)/(dt)=(dx)/(dt)+2 (2y)/(2sqrt(h^(2)+y^(2))) (dy)/(dt)`

`implies 0=v+(2y)/(sqrt(h^(2)+y^(2)))(-u)`
`implies 0=v-2u cos theta implies u=v//cos theta`
(b) Length of string, `l=2x+2sqrt(h^(2)+y^(2))`
Again differentiate to get `u=v//cos theta`.