The temperature of a pan of hot water varies according to newton's law of cooling: dt dt equals negative k times the quantity t minus a , where t is the water temperature, a is the room temperature, and k is a positive constant. if the water cools from 90°c to 85°c in 1 minute at a room temperature of 30°c, how long (to the nearest minute) will it take the water to cool to 60°c?

Four point charges each having charge q are located at the corners of a square having sides of length a. find symbolic expressions for the following. (a) the total electric potential at the center of the square due to the four charges (use any variable or symbol stated above along with the following as necessary: ke.) vtotal= (b) the work required to bring a fifth charge p from infinity to the center of the square (use any variable or symbol stated above along with the following as necessary: w=

Astep up transformer has 250 turns on its primary and 500 turns on it secondary. when the primary is connected to a 200 v and the secondary is connected to a floodlight that draws 5a, what is the power output? show all of your work.

The molecular mass of a gas is (select all that apply) a. independent of the type of gas b. the same number as the atomic (or molecular) mass, but measured in grams c. dependent on the temperature d. the mass of a mole of the gas