1. The problem statement, all variables and given/known data Ball A is dropped from the top of a building of height h at the same instant that ball B is thrown vertically upward from the ground. At what height will the balls collide if the collision occurs when the balls are moving in the same direction and the speed of A is 4 times that of B. VA0 = 0 - the internal speed of ball A. h=h; a=g; tc - the time when the balls collide. VA(tc)=4*VB(tc) 2. Relevant equations v = v(initial) +at x = x(initial) + v(initial)t + (at^2)/2 3. The attempt at a solution XA(tc)=XB(tc)=hc (height whenn the balls collide) XA(tc)= h-(g*(tc)2)/2 XB(tc)= XB(tb) - XB(tb→tc)= =VBO - (g*(tb)2)/2 - (g*(tc-tb)2)/2= =VBO - (g*(tb)2) - (g*(tc)2)/2 + g*tc*tb V(tb)=0 ⇒VB0=g*tb⇒ ⇒XB(tc)=g*tc*tb - (g*(tc)2)/2 XA(tc)=XB(tc)= h=g*tc*tb VA(tc)=4*VB(tc) ⇒ -g*tc = -g*(tc-tb) ⇒ 3tc= 4tb →witch is impossible!