In Case 1, a spring launches a cart toward an incline and the cart rises a height H = 4 m up an incline before coming momentarily to rest. In Case 2, the cart is launched exactly the same way, but collides and sticks with an identical cart before encountering the incline. How high does the two-cart system rise up the incline in Case 2? Justify your answer.

In Case 1, a spring launches a cart toward an incline and the cart rises a height H = 4 m up an incline before coming momentarily to rest. In Case 2, the cart is launched exactly the same way, but collides and sticks with an identical cart before encountering the incline. How high does the two-cart system rise up the incline in Case 2? Justify your answer.