Advertisements
Advertisements
Question
Draw a neat labelled diagram showing a pulley being used to lift a load. How are load and effort related in an ideal situation?
Advertisements
Solution
To raise a load, the load is attached to one end of the string and the effort is applied at the other end by pulling it is a downward direction . as shown in fig.
APPEARS IN
RELATED QUESTIONS
Is the above pulley system an ideal machine or not?
Fill in the blank:
A pulley is used to change ........................
What is a single movable pulley? What is its mechanical advantage in the ideal case?
Give two reasons why the efficiency of a single movable pulley system is not 100%.
The diagram below shows a pulley arrangement :
(i) Copy the diagram and mark the direction of tension on each strand of the string.
(ii) What is the velocity ratio of the arrangement ?
(iii) If the tension acting on the string is T, then what is the relationship between T and effort E ?
(iv) If the free end of the string moves through distance x, find the distance by which the load is raised.
(a) Fig represents an incomplete diagram of a simple string pulley system. Copy this diagram on a new page and complete it and mark where the effort must be applied to lift the load.
(b) What is the velocity ratio of this system?
(c) If the pulley system is 80% efficient and the load is 720 N, then
(i) What effort must be applied to lift the load?
(ii) What work must be done must be done in lifting the load through a distance of 2 m using this machine?
What is the relation between the mechanical advantage and the number of strands of string used to support the load, in a ‘block and tackle’ set-up?
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.
| Meera chose to use a block and tackle system of '9' pulleys instead of a single movable pulley to lift a heavy load. |
Why should she connect more number of pulleys in the upper fixed block?
