Answer:
470 rad/s
Explanation:
The acceleration of the motor shaft is:
γ1 = 4*w1^(3/4)
When connected by a belt the pulleys have the same tangential speed
vt = w * r
vt1 = vt2
w1 * r1 = w2 * r2
w2 = w1 * r1/r2
Therefore:
γ2 = 4 * (w1 * r1/r2)^(3/4)
d(w1 * r1/r2)/dt = 4 * (w1 * r1/r2)^(3/4)
(r1/r2) * dw1/dt = 4 * (r1/r2)^(3/4) * (w1 * r1/r2)^(3/4)
dw1/dt = 4 * (r1/r2)^(-1/4) * (w1)^(3/4)
This is a differential equation.
Solving it through Wolfram Alpha:
w1(t) = (1 / 256) * (4 * (r1/r2)^(-1/4) * t - 4)^4
w1(4) = (1 / 256) * (4 * (0.25 / 1)^(-1/4) * 4 - 4)^4 = 470 rad/s