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for the first one you use f=ma, where a=v squared/r. so you want to find the angle where that will push inward just as hard as the car is accelerating outward. so sin(theta)*m=m(v squared/r). The ms cancel out, so sin(theta)=v sqaured/r. On your calcuator you can do inverse sin of v squared/r.
I think you use the force eqn f=gm/r or something like that.
Sorry if these arent right, im a little rusty.