(English Medium) ICSE Class 10 - CISCE Question Bank Solutions for Physics

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?

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.

A type of single pulley is very often used as a machine even though it does not give any gain in mechanical advantage. For what purpose is such a pulley used?

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?

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?

In the alongside the figure of two pulleys shown a system in which one pulley is fixed and the other is movable. What is the velocity ratio of the system?
An effort of 600 N is needed to lift a weight of 1000 N. What are the mechanical advantage and efficiency of the pulley system?

What is a pulley?

Draw the diagram of a single movable pulley and obtain its mechanical advantage, velocity ratio, and efficiency.

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.

The pulley system shown in the figure is to be used to lift a load W. If the man applying the effort cannot apply a force exceeding 1000 N, what is the maximum load that can be lifted?
The actual load that the man is finally able to lift turns out to be 2700 N. What are the values of the actual M.A., obtained, and the efficiency of the actual set-up?

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.

Draw a diagram showing a block and tackle system of 4 pulleys.

(i) State, how many strands of tackle support the load?
(ii) Draw arrows to represent tension in each strand.
(iii) Find the mechanical advantage of the system, stating the assumptions made.
(iv) If the load is pulled up by a distance 1m, how much does the effort end move?

A block and tackle system of pulleys has a velocity ratio of 4.

1. Draw a labelled diagram of the system indicating clearly the points of application and directions of load and effort.
2. What is the value of the mechanical advantage of the given pulley system if it is an ideal pulley system?

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.

In a single movable pulley system, a load of 125 kgf is lifted by an effort of 75 kgf. Find the percentage efficiency of system.

A man raises a load of 360 kgf using a block and tackle system of 3 pulleys. If the efficiency of the pulley system is 60%, what effort is applied by the man?

If the weight of the movable pulley is W, obtain the expression for MA, VR, and efficiency.

A pulley system has a velocity ratio of 4 and an efficiency of 90%. Calculate:
(i) the mechanical advantage of the system.
(ii) the effort required to raise a load of 300 N by the system.

A ‘block and tackle’ system used 3 pulleys in the lower block and 4 pulleys in the upper block. What is the ‘velocity ratio’ of this system? If the load is to be lifted by a person capable of applying a maximum effort of 1000 N, what is the maximum load than can be lifted under ideal conditions?
The actual maximum load that gets lifted turns out to be 6300 N. What are the values of the actual M.A. and efficiency of the set-up?