Krotov

110 Aptitude Test Problems in Physics while the second body moves towards it at a velocity vl + v2. Its acceleration is constant, equal in magnitude to al -|·· az, and is directed against the initial velocity. ‘The condition that the bodies meet indicates that the distance over which the velocity of the second body vanishes must belonger than the separation between the bodies at the beginning of motion; hence we obtain I I =___ (vi-!-v¤)“ ma 2 (*11+ ¤¤) ' 1.6. Since the balls move along the vertical, we direct the coordinate axis vertically upwards. We plot the time dependence of the projections of the velocities of the balls on this axis. Figures 122 D7 L°; up + ` lll M k\E `"2"r "vh · ·»l·i·· — wl-}- ·· ·+· Fig. 122 UZ tz fg - .._......

2 va _ if Fig. 123 and 123 show the dependences v1 (t) and v, (t) respectively (the moments of the beginning of motion are not matched so far). These graphs present infinite sets of straight line segments with e ual slopes (since the acceleration is the same). These