If a person bends at the waist with a straight back making an angle of o degrees with the horizontal, then the foroe Fexerted on the back musdes can be modeled by the equation 0.6W sin(a- 30") sin12" where W is the weight of the person. a) Calculate force Ffor W= soband @- 45 b) Use an identy to show that Fis approximately equal to 29 Wcose c) For what value of a is F maximum?