a) Find the force exerted by the rope on the car, when the angle theta is 3 degrees, and you are pulling with a force of 400, but the car does not move.
b) How strong must the rope be if it takes a force of 600N on your part to move the car when theta is 4 degrees?
See the attached figure for details.
a) r=g/(2*sin(theta)) = 400/(2*sin(3)) = 3821 ...
This solution provides the level of force needed to move a car, with a specified angle given. This is determined by using Newton's laws and by looking at angle properties.