A. Double if only one block moves. Quadruple if both move.
Q. Describe the gun-tackle.
A. A rope passed through two single blocks and made fast to one. (See Fig. 49.)
Q. What is the power gained?
A. Double. Treble if block to which rope is made fast moves.
Q. Describe the luff-tackle.
A. A rope hove through a single and a double block and made fast to the single block. (See Fig. 49.)
Q. What is the power gained?
A. Treble. Quadruple if the block moves.
Q. What is a luff upon luff?