Omar wrote a hypothesis about batteries called dry cells. If more dry cells are connected end to end, a light bulb will work longer because there is more energy available. What are the variables in his hypothesis? The independent variable is the number of dry cells, and the dependent variable is the length of time the bulb works. The independent variable is the length of time the bulb works, and the dependent variable is the number of dry cells. The independent variable is the number of dry cells, and the dependent variable is the amount of energy available. The independent variable is the amount of energy available, and the dependent variable is the number of dry cells.

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?

How does the kinetic energy of a charge change as the charge moves under the effect of an electric field from higher potential to lower potential? a.the kinetic energy increases.b.the kinetic energy decreases.c.the kinetic energy remains the same.d.the kinetic energy is always zero.

An object's buoyant force and weight mean the same thing.a. trueb. false