What is the power usage of a device that uses 3.0 A of current at a voltage of 120 V? How much energy (in kilowatt-hours) does this device use if it is left on for 2.0 hr?

An object weighs 40n in air, weighs 20n when submerged in water and 30n when submerged in a liquid of unknown density. what is the density of the liquid?

In a heat engine if 1000 j of heat enters the system the piston does 500 j of work, what is the final internal energy of the system if the initial energy was 2000 j? 1. write the equation 2.list out your known variables 3.plug the numbers into the equations 4.solve 5.write your solution statement that includes initial energy and final

Which is the correct symbol for an isotope of iodine with 53 protons and 78 neutrons?