In figure shown on the right, the mass of the trolley is 100 kg, and it can move without friction on the horizontal floor. Its length is 12m. The mass of the girl is 50 kg. Friction exists between the shoes of the girl and the trolley’s upper surface, with $\mu =1/3.$ The girl can run with a maximum speed = 9 m/s on the surface of the trolley, with respect to the surface. At t = 0 the girl starts running from rest to the right. The trolley was initially stationary. ( $g=10m/s^2$ )