788 Work and Energy 2 Work done by several forces ifF=h+F2+}3+F4+ W=∫FdF=「FdF+dF+,dF+ =W+W,+W2+ The work done by several forces = algebraic sum of the work done by the individual force. ◆合力的功=分力的功的代数和7&8 Work and Energy if       F = F1 + F2 + F3 + F4 +           = + + + =  =  +  +  +     1 2 3 1 2 3 W W W W F d r F d r F dr F dr The work done by several forces = algebraic sum of the work done by the individual force. 2 Work done by several forces 合力的功 = 分力的功的代数和