A 250 g blob of clay moves with a speed of 15 m/s towards a 400 g cart that is initially at rest. a). What is the momentum of the system before the blob of clay strikes the cart? b). What must be the momentum of the system after they come together? ( Please note, a response of "the same " is insufficient and will result in minimal credit). c. If the blob of clay sticks to the cart, with what speed will the clay and cart move after they come together?