Both objects A and D represent fixed, negatively-charged particles of equal magnitude and Object B represents a fixed, positively-charged particle (equal, but opposite charge from A and D). Object C shows a moving, positively-charged particle. Identify which arrow would correctly show the force of attraction or repulsion on object C caused by the other two objects?
A) 1
B) 2
C) 3
D) 4

Awelder using a tank of volume 7.50×10^-2 m^3 fills it with oxygen (with a molar mass of 32.0 g/mol ) at a gauge pressure of 3.30×10^5 pa and temperature of 37.1 ∘c. the tank has a small leak, and in time some of the oxygen leaks out. on a day when the temperature is 23.1 ∘c, the gauge pressure of the oxygen in the tank is 2.00×10^5 pa . a) find the initial mass of oxygen. b) find the mass of oxygen that has leaked out.