A 4 gram piece of Zinc, with a specific heat of .388J/gC, is heated in a Bunsen Flame for 20 seconds. The zinc is then placed in a 45 ml water calorimeter. The calorimeter increased its temperature from 22.0 degrees Celsius to 23.2 degrees Celsius. What was the initial temperature of the metal after heating?

Rohit is trying to tune an instrument

The electric field between square plates of a parallel-plate capacitor has magnitude e. the potential across the plates is maintained with constant voltage by a battery as they are pulled apart to twice their original separation, which is small compared to the dimensions of the plates. the magnitude of the electric field between the plates is now equal to a)e b)e/4 c)e/2 d)4e e)2e

Two identical stars with mass m orbit around their center of mass. each orbit is circular and has radius r, so that the two stars are always on opposite sides of the circle. (a) find the gravitational force of one star on the other. (b) find the orbital speed of each star and the period of the orbit. (c) how much energy would be required to separate the two stars to infinity?