Diego is trying to lift a piano to the second floor of his house. Diego uses a pulley system and gives a big lift to the piano. The piano moves upward, then stops, and then it starts to fall to the ground.

Which list best describes the forces on the piano in the proper order?

A. positive force → balanced force → negative force
B. negative force → balanced force → positive force
C. positive force → unbalanced force → negative force
D. negative force → unbalanced force → positive force

Clothing made of several thin layers of fabric with trapped air in between, often called ski clothing, is commonly used in cold climates because it is light, fashionable, and a very effective thermal insulator. so it is no surprise that such clothing has largely replaced thickand heavy old-fashioned coats. (a) consider a jacket made of five layers of 0.1-mm-thick synthetic fabric (k = 0.13 w/m·°c) with 1.5-mm-thick air space (k = 0.026 w/m·°c) between the layers. assuming the inner surface temperature of the jacket to be 28°c and the surface area to be 1.25 m2, determine the rate of heat loss through the jacket when the temperature of the outdoors is 0°c and the heat transfer coefficient at the outer surface is 25 w/m2·°c. (b) what would your response be if the jacket is made of a single layer of 0.5-mm-thick synthetic fabric? what should be the thickness of a wool fabric (k = 0.035 w/m·°c) if the person is to achieve the same level of thermal comfort wearing a thick wool coat instead of a five-layer ski jacket?

What happens when the number of protons in an atom changes

What is a possible explanation for a set of facts that can be tested by further investigations called