Please help me. I need both questions

What is the magnitude of the resultant vector round your answer to the nearest tenth

According to newton’s first law of motion, which force is expected to cause a body to accelerate?

Agas initially at p1 = 1 bar and occupying a volume of 0.5 liter is compressed within a piston–cylinder assembly to a final pressure p2 = 4 bar. (a) if the relationship between pressure and volume during the compression is pv = constant, determine the volume, in liters, at a pressure of 3 bar. (b) repeat for a linear pressure–volume relationship between the same end states. reference