## Question:

A solid-fueled rocket can be made using a fuel grain with either a hole (a), or starred cavity (b), in the cross section. From experiment the engine thrust-time curves (T vs. t) for the same amount of propellant using these geometries are shown. Determine the total impulse in both cases. Given: ${ T }_{ 1a }$ = 4 lb , ${ t }_{ 1a }$ = 3 s , ${ T }_{ 1b }$ = 8 lb , ${ t }_{ 1b }$ = 6 s , ${ T }_{ 2a }$ = 6 lb , ${ t }_{ 1c }$ = 10 s , ${ t }_{ 2a }$ = 8 s , ${ t }_{ 2b }$ = 10 s