Advertisements
Advertisements
प्रश्न
Answer the following in detail.
How does a pulley make work simpler?
Advertisements
उत्तर
A pulley is a wheel or a circular disc that can rotate freely about its axle. It is used to lift heavy objects. It is neither a force multiplier nor a speed multiplier. It only changes the direction of the applied force from upwards against gravity to downwards towards gravity. There are two types of pulley systems – Single fixed pulley and single movable pulley.
APPEARS IN
संबंधित प्रश्न
Draw a neat labelled diagram showing a pulley being used to lift a load. How are load and effort related in an ideal situation?
Answer the following in short.
Explain the various functions that a machine can perform.
Explain the working of a gear system.
What should be the gear ration of a car : equal to 1, less than 1 or greater than 1, while ascending a hill ?
Give reason for the following:
The lower block of a block and tackle pulley system must be of negligible weight
What is a block and tackle system of pulleys?
In the case of a block and tackle arrangement, the mechanical advantage increases with the number of pulleys. Explain.
State two reasons, why the efficiency of a pulley system is not 100 percent?
The alongside figure shows the combination of a movable pulley P1 with a fixed pulley P2 used for lifting up a load W.
(i) State the function of the fixed pulley P2.
(ii) If the free end of the string moves through a distance x, find the distance by which the load W is raised.
(iii) Calculate the force to be applied at C to just raise the load W = 20 kgf, neglecting the weight of the pulley P1 and friction.
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.
