Advertisements
Advertisements
प्रश्न
The diagram below shows a pulley arrangement.
- Name the pulleys A and B.
- In the diagram, mark the direction of tension on each strand of string.
- What is the purpose of the pulley B?
- If the tension is T, deduce the relation between
- T and E, and
- E and L.
- What is the velocity ratio of the arrangement?
- Assuming that the efficiency of the system is 100%, what is the mechanical advantage?
Advertisements
उत्तर
- Pulley A is a movable pulley.
Pulley B is a fixed pulley. - Tension T is marked in (f)
-
Pulley B's function is to reverse the direction of effort applied, moving it from upward to downward.
- Relation between:
- T and E are E = T.
- Between E and L, is E = `L/2`
- V.R. = `("Distance moved by effort" d_E)/("Distance moved by load" d_L)`
V.R. = `(2d)/d = 2` - M.A. = Efficiency × V.R.
= `100/100 xx 2 = 2`
APPEARS IN
संबंधित प्रश्न
Select the correct alternative:
A pulley is used because of it
The mechanical advantage of an actual pulley is less than one. Give a reason. What is the justification for using the pulley then?
What is a gear system ?
A block and tackle pulley system has a velocity ratio 5. Draw a labelled diagram of this system. In your diagram, indicate clearly the points of application and the directions of the load and effort.
Give reason for the following:
In case of a block and tackle arrangement, the mechanical advantage increases with the increase in the number of pulleys.
Give reason for the following:
The efficiency of a pulley is always less than 100%
A type of single pulley is very often used as a machine even though it does not give any gain in mechanical advantage. Name the type of pulley used.
Diagram given below shows an arrangement of four pulleys. A load L is attached to the movable lower block and effort E is applied at the free end of the string.
Copy the diagram; and
(i) Draw arrows to indicate tension in each part of the string; and
(ii) Calculate the mechanical advantage of the system.
Complete the table.
| S. No | Types of Simple Machine | Example |
| 1. | Pulley | |
| 2. | Wheel and axle | |
| 3. | Wedge | |
| 4. | Inclined plan | |
| 5. | Lever | |
| 6. | Screw |
A block and tackle system of pulleys has a velocity ratio of 4.
- Draw a labelled diagram of the system indicating clearly the direction of the load and effort.
- Calculate the potential energy of the load 100 kgf lifted by this pulley to a height 5 m. (g = 10 ms−2)
