A cup of hot coffee sits on your desk. Assume that the thermal energy in the coffee can be converted with an efficiency of 100%% to gravitational potential energy of the coffee-Earth system-enough so that the coffee rises up above the rim of the cup. Let the height of the coffee rise by 4.2 cmcm .Find the magnitude of the drop in temperature needed to accomplish this energy conversion. Use c = 4180 J/kg⋅∘C for coffee.

Achlorine atom has 17 protons and 18 neutrons. what is its mass number? what is its atomic number?

Two conductors, a and b, are each in the shape of a tetrahedron. but of different sizes. they are charged in the following manner: 1. tetrahedron a is charged from an electrostatic generator to charge q. 2. tetrahedron a is briefly touched to tetrahedron b. 3. steps 1 and 2 are repeated until the charge on tetrahedron b reaches a maximum value. if the charge on tetrahedron b was q/4 after the first time it touched tetrahedron a. what is the final charge qbmax on tetrahedron b?

Aball is thrown from the top of a building with an initial velocity of 21.9 m/s straight upward, at an initial height of 51.6 m above the ground. the ball just misses the edge of the roof on its way down, as shown in the figure. (a) determine the time needed for the ball to reach its maximum height. (b) determine the maximum height. (c) determine the time needed for the ball to return to the height from which it was thrown, and the velocity of the ball at that instant. (d) determine the time needed for the ball to reach the ground. (e) determine the velocity and position of the ball at t = 5.35 s.