A 193 kg curtain needs to be raised 7.5 m at a constant speed, in as close to 5 s as possible. The power ratings for 3 motors are listed as 1.0 kW, 3.5 kW and 5.5 kW. Which motor is best for the job?

molecules are free to separate from each other and will take on the shape of the container. molecules move completely at random and high speeds. they vibrate in a fixed position and do not move around much. molecules expand to the edge of their container.

answer: 31, 5556. 952 seconds

t = 1/400 h   ⇔ 0.0025 h ⇔ 9s ⇔ 0.15 m

any of the answers are correct.