Cart A is traveling south when it collides with cart B, which is traveling west. Cart A has a mass of 4 kg, and cart B has a mass of 2 kg. The two carts travel together as a single object on a horizontal surface at an angle of 30 relative to the south, as shown above. In one trial, the initial speed of cart B is 6 m/s. The speed of the carts when they move together is most nearly A. 2 m/s
B. 4 m/s
C. 6 m/s
D. 8 m/s
E. There is not enough information to find the speed