How long will it take a 2750-W motor to lift a 385-kgpiano to a sixth-story window 16.0 m above?

To solve this problem, we need to use the formula for work, which is work = force x distance.

1. First, we need to calculate the force. The force is equal to the weight of the piano, which is mass x gravity. The mass is 385 kg and gravity is approximately 9.8 m/s^2. So, the force is 385 kg x 9.8 m/s^2 = 3773 N.

2. Next, we calculate the work done. The work is equal to the force x distance. The force is 3773 N and the distance is 16.0 m. So, the work is 3773 N x 16.0 m = 60368 J (Joules).

3. Now, we can calculate the time. The power of the motor is work/time. So, time = work/power. The work is 60368 J and the power is 2750 W. So, the time is 60368 J / 2750 W = 21.95 s.

So, it will take approximately 22 seconds for the 2750-W motor to lift the 385-kg piano to a sixth-story window 16.0 m above.