How long does it take to use a 900 W crane to lift a 325 kg piano through a sixth floor window 16 m above the sidewalk?

The power of the crane can be calculated using the formula:
P = A / t, where P is the power of the crane (P = 900 W), A is the work when lifting the piano (A = Ft * h, where Ft is the acting gravity (Ft = m * g, where m is the mass of the piano) (m = 325 kg), g is the acceleration of gravity (g = 10 m / s ^ 2)), h is the height to which the piano was raised (h = 16 m)), t is the ascent time (s).
P = A / t = m * g * h / t.
Let’s express and calculate the rise time of the piano:
t = m * g * h / P = 325 * 10 * 16/900 ≈ 58 s.
Answer: The rise time of the piano is 58 seconds.