How much heat is required to raise the temperature of an empty 20kg object made of iron from 10^°C to 90^°C

Balloon a has charge q, and identical mass balloon b has charge 10q. you hang them from threads near each other. choose all of the statements with which you agree. check all that apply. a. a and b exert the same magnitude forces on each other. b. the force that a exerts on b is 10 times the force that b exerts on a. c. the angle between the thread supporting a and the vertical is < the angle between the thread supporting b and the vertical. d. the force that a exerts on b is 1/10 the force that b exerts on a.

What are the necessary conditions for fusion?

Ryan is examining the energy of the particles in a bar of gold. what is ryan most likely studying?