solve( 0 + 0 = 5 * 9.8 * (-1.25) + 3.5 * 9.8 * 1.25 + 1/2 * (5+3.5) * v^2 , v); float(%);
solve( 1/2 * 0.4 * v^2 = 0.4 * 9.8 * 20, v); float(%);