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
A pulley system with VR = 4 is used to lift a load of 175 kgf through a vertical height of 15 m. The effort required is 50 kgf in the downward direction. (g = 10 N kg-1)
Calculate:
- Distance moved by the effort
- Work done by the effort
- M.A. of the pulley system
- Efficiency of the pulley system
What is the justification for using the pulley then ?
Answer the following in short.
Explain the various functions that a machine can perform.
What is a gear system ?
What should be the gear ration of a car : equal to 1, less than 1 or greater than 1, while gaining speed on the road ?
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
Fig shown a block and tackles system of pulleys used to lift a load.
(i) How many strands of tackle are supporting the load?
(ii) Draw arrows to represent tension in each stand.
(iii) What is the mechanical advantage of the system?
(iv) When load is pulled up by a distance 1 m how far does the effort end move?
In the case of a block and tackle arrangement, the mechanical advantage increases with the number of pulleys. Explain.
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?
Draw a diagram of a single fixed pulley and obtain expressions for its:
(i) Mechanical advantage,
(ii) Velocity ratio, and
(iii) Efficiency, in the ideal case.
