A 1000 kg car goes around a turn in the road that has a radius of curvature of 50 m. The car is traveling at a constant speed of 12 m/s. Is the car accelerating? Why or why not? What is the direction of the acceleration?

A body accelerates only when there is change in its magnitude or direction . and here

even if the magnitude is not changing ( remains constant ) the direction changes , hence the car is accelerating.

and since the car turns it's direction keep changing.

one person pulls 90n one way and the other has 100n pulling the other way.

so the net force = 90 - 100 = -10n,

or the ans can be 10n if the picture shows -90n and 100n instead.