How far must you stretch a spring with k = 1600 n/m to store 260 j of energy?

Describe how the fermi level changes with donor level, temperature and contact with p and n type semiconductors

Africtionless piston-cylinder contains 50 l of saturated liquid r-134a. the piston has a mass and an area resulting in an applied pressure of 500 kpa on the refrigerant. the refrigerant is now heated until its temperature rises to 70∘c. calculate the work (in kj) done during this process.

How do you tell if someone actually cares about you? and just say they do?