Asmall sphere is hung by a string from the ceiling of a van. when the van is stationary, the sphere hangs vertically. however, when the van accelerates, the sphere swings backward so that thestring make an angle of θ with respect to the vertical.(a) derive an expression for the magnitude a of theacceleration of the van in terms of the angle θ and themagnitude g of the acceleration due to gravity.(b) find the acceleration of the van when θ =10.0 ο(c) what is the angle θ when the van moves with theconstant velocity ?