The net force exerted by a woodpecker's head when its beak strikes a tree can be as large as 4.90 N, assuming that the bird's head has a mass of 50.0 g. If the forces exerted by the muscles are at right angles to each other and the muscle that pulls the woodpecker's head downward exerts a force of 1.70 N, what is the magnitude of the force exerted by the other muscle?