If a 1672 kg car, moving at 10 m/s north, hits and sticks to a 2542 kg truck, moving at 7 m/s east, find the magnitude of the final speed. Hint: here the masses are moving north and east (or in the x & y directions) - so it's a two dimensional problem. Just like all other two dimensional problems we need to separate the x and y motions, treat each separately, and the put the two directions back together. Use the "hit and stick" or inelastic formula use the inelastic collision formula in the x-dir, only using the x-components of the two velocities use the inelastic collision formula in the y-dir, only using the y-components of the two velocities use the Pythagorean Theorem to combine the x & y components so as to get the magnitude of the final velocity use arcTan(vy' / vx') to get the direction of the final velocity if the angle doesn't end up in the first quadrant, then fix the angle