Advertisements
Advertisements
Question
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.
Advertisements
Solution
This is because mechanical advantage is equal to the total number of pulleys in both the blocks.
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
A block and tackle system has V.R. = 5.
Draw a neat labeled diagram of a system indicating the direction of its load and effort
Fill in the blank:
A pulley is used to change ........................
What is the mechanical advantage of an ideal pulley?
Answer the following in short.
Explain the various functions that a machine can perform.
Define the following term in reference to a gear system for Gain in torque ?
State two reasons, why the efficiency of a pulley system is not 100 percent?
What is a block and tackle system of pulleys? What precautions would you observe while rounding the string so that the effort is applied in the downward direction?
If the weight of the movable pulley is W, obtain the expression for MA, VR, and efficiency.
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.
