1. Two objects moving with a speed 1: travel in opposite directions in a straight line. The objects stick together when they collied, and move with a speed of vl- after collision a. What is the ratio of the final kinetic energy of the system to the initial kinetic energy? b. What is the ratio of the mass of the more massive object to the less massive object? 2. A child sits in a wagon with a pile of 0.65kg rocks. If she can throw each rock with a speed of limits relative to the ground, causing the wagon to move, how many rocks must she throw per minute to maintain a constant average speed against a 3,4N force of friction?r 3. A semi-circular wire is formed with the help of a wire oflength 1. Find the position of the center of mass of the semicircular wire from the point \"0\" as shown in the figure 4. Find the center of mass (XCMJCM) of the pile of bricks stacked as shown in the gure below. The dimensions of the bricks (length, width) is given as (l, w)