2.The solid steel shaft AB is to be used as a torsion bar. Bar BC is a rigid horizontal member. Specifications require that a 2500 pound force P at C is to cause no more than a 0.9 inch vertical deflection of point C as shown in Figure 2-1, Find the minimum required diameter of the bar AB. Bearing will ensure that the bar AB will be in pure torsion. Use 12 xl06 Ib/in2 for the modulus of rigidity. Hint: As shown in Figure 2-2, what is φ? ( 20%)