The 9 kg block is then released and accelerates

to the right, toward the 2 kg block. The

surface is rough and the coefficient of friction

between each block and the surface is 0.5. The

two blocks collide, stick together, and move

to the right. Remember that the spring is not

attached to the 9 kg block.

Find the speed of the 9 kg block just before

it collides with the 2 kg block.

Answer in units of m/s.