Question

.

Answer 1

we know
50^2 = x^2 + y^2 ....(1)
differentiate both sides w.r.t t
0 = 2x dx/dt + 2y dy/dt
0 = 2x(v_x) +2y ( -v_y)

here, v_x means x is in the subscript,same with v_y

and its -v_y since y is decreasing..

thus you have

v_x / v_y = y/x
for v_x = v_y
we have y=x

now you know this and also from eqn(1) , you can calculate x and y..