A man uses a single movable pulley to lift a heavy load with a frictionless rope.
Which of the following pulley systems have/has a greater mechanical advantage than the one shown above?
W.
X.
Y.
Z.
Pulleys at the top of the rope are fixed.
A.
Z only
B.
W and Y
C.
W only
D.
W and X
Answer-
W only
Explanation-
Fixed pulleys do not change the mechanical advantage of a system. Movable pulleys that increase the number of sections of rope that bear the weight of the load increase the mechanical advantage of the system. The top image has one movable pulley. Only system W has more than one movable pulley—it has two.
