?????? ????? ??????? ?? ??????? ?????? ??? ?????? ??????? ?????? ???? ?????? ????? ??????? ???????? ??? ???? ?????? ?????? ???? ?????? ???? ?? ???? ??? ??????? ????? ???? ????? ????? ????? ???: ???? ???? ???? ?? ??????? ?? ????? ?????? ????????. A lever is really a bar or board that rests on the aid called a fulcrum. A downward force exerted o