Notice that we have the weight of the crane exerting a torque about the front wheels of the same crane. to create a torque, a force must be present, so it would seem that somehow the weight of the crane is exerting a force upon its front wheels. however, the crane is one object, and it follows from newton's laws that an object cannot exert a net force upon itself. this crane seems to be defying newton's laws. what's going on here?