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प्रश्न
The diagram below shows an arrangement of three pulleys A, B, and C. The load is marked as L and the effort as E.
- Name the Pulleys A, B, and C.
- Mark in the diagram the directions of load (L), effort (E) and tension T1 and T2 in the two strings.
- How are the magnitudes of L and E related to the tension T1?
- Calculate the mechanical advantage and velocity ratio of the arrangement.
- What assumptions have you made in parts (c) and (d)?
उत्तर
(a) Pulleys A and B are movable pulleys. Pulley C is a fixed pulley.
(b)
(c) L = 4T1; E = T1
(d) M.A. = `L/E`
M.A. = `(4T_1)/T_1`
M.A. = 4
V.R. = `(4d)/d = 4`
(e)
- There is less weight on pulleys A and B.
- There's no friction at all between the axle and the pulleys.
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संबंधित प्रश्न
State whether the following statement is True or False.
A pulley changes the direction of force.
Define the following term in reference to a gear system for Gain in torque ?
What is a block and tackle system of pulleys?
The diagram below shows a pulley arrangement.
(i) In the diagram, mark the direction of the forces due to tension, acting on the pulley P.
(ii) What is the purpose of the pulley Q?
(iii) If the tension is T newton, deduce the relation between T and E.
(iv) Calculate the velocity ratio of the arrangement.
(v) Assuming that the efficiency of the system is 100%, what is the mechanical advantage?
(vi) Calculate the value of E
Name a machine which is used to:
change the direction of force applied.
There is no gain in mechanical advantage in the case of a single fixed pulley. Explain, why the pulley is then used?
In the case of a block and tackle arrangement, the mechanical advantage increases with the number of pulleys. Explain.
Draw a diagram showing a block and tackle system of 4 pulleys.
(i) State, how many strands of tackle support the load?
(ii) Draw arrows to represent tension in each strand.
(iii) Find the mechanical advantage of the system, stating the assumptions made.
(iv) If the load is pulled up by a distance 1m, how much does the effort end move?
A boy lifts a load of 40 kgf through a vertical height of 2m in 5s by using a single fixed pulley when he applies an effort of 48 kgf. Calculate:
(i) the mechanical advantage, and
(ii) the efficiency of the pulley. Why is the efficiency of the pulley is not 100%?
(iii) the energy gained by the load in 5s, and
(iv) the power developed by the boy in raising the load.
Name the type of single pulley that has an ideal mechanical advantage equal to 2. Draw a labelled diagram of the pulley mentioned by you.
