The electrostatic force between two positive point charges is f when the charges are 0.1 meter apart. when these point charges are placed 0.05 meter apart, the electrostatic force between them
a) a f and repelling
b) 1/4f and repelling
c) 4f and attracting
d) 1/4f and attracting

*if you could tell me how you got this answer that would be great as i'm very lost on this one

Acommercial refrigerator with refrigerant-134a as the working fluid is used to keep the refrigerated space at -35°c by rejecting waste heat to cooling water that enters the condenser at 18°c at a rate of 0.25 kg/s and leaves at 26°c. the refrigerant enters the condenser at 1.2 mpa and 50°c. if the compressor consumes 3.3 kw of power, determine (a) the mass flow rate of the refrigerant, (b) the refrigeration load, (c) the cop, and (d) the minimum power input to the compressor for the same refrigeration load.