Figure shows a system of four pulleys. The upper two pulleys are fixed and the lower two are movable.

(a) Draw a string around the pulleys. Also show the point of application and direction in which the effort E is applied.

(b) What is the velocity ratio of the system?

(c) How are load and effort of the pulley system related?

(d) What assumption do you make in arriving at your answer in part (c)?

Figure shows a block and tackle system of pulleys used to lift a load.

(a) How many strands of tackle are supporting the load?

(b) Draw arrows to represent tension T in each strand.

(c) What is the mechanical advantage of the system?

(d) When load is pulled up by a distance 1 m, how far does the effort end move?

(e) How much effort is needed to lift a load of 100 N?

(f) What will be its V.R. if the weight of the movable block is doubled?

A block and tackle system has 5 pulleys. If an effort of 1000 N is needed in the downward direction to raise a load of 4500 N,

Calculate —

(a)The mechanical advantage,

(b)The velocity ratio and,

(c)The efficiency of the system.

In figure draw a tackle to lift the load by applying the force in the downward direction.

(a) Mark in the diagram the direction of load L and effort E.

(b) If the load is raised by 1 m, through what distance will the effort move?

(c) State the number of strands of tackle supporting the load.

(d) What is the mechanical advantage of the system?