When a click beetle is upside down on its back, it jumps upward by suddenly arching its back, transferring energy stored in a muscle to mechanical energy. This launching mechanism produces an audible click, giving the beetle its name. Videotape of a certain click-beetle jump shows that a beetle of mass m = 4.0 x 10^-6 kg moved directly upward by 0.77 mm during the launch and then to a maximum height of h = 0.30 m. During the launch, what are the average magnitudes of 

(a) The external force on the beetle's back from the floor and 

(b) The acceleration of the beetle in terms of g?