which formula would you use for question 4.2 and why?Do the cat and skate board count as one object ?

QUESTION 4 (Start on a new page.) The diagram below shows two skateboards, A and B. initially at rest, with a cat standing on skateboard A. The skateboards are in a straight line, one in front of the other and a short distance apart. The surface is flat, frictionless and horizontal. cat A B O O surface 4.1 State the principle of conservation of linear momentum in words. (2) EACH skateboard has a mass of 3,5 kg. The cat, of mass 2,6 kg, jumps from skateboard A with a horizontal velocity of 3 m.s" and lands on skateboard B with the same velocity of 3 m.s. Refer to the diagram below. 3 m.5-1 cat B A surface O O O 4.2 Calculate the velocity of skateboard A just after the cat has jumped from it. (5) Immediately after the cat has landed, the cat and skateboard B move horizontally to the right at 1,28 m.s. 4.3 Calculate the magnitude of the impulse on skateboard B as a result of the (3) cat's landing. [10]