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

Define the following term in reference to a gear system for Gain in speed ?

Define the following term in reference to a gear system for Gain in torque ?

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 ?

What should be the gear ration of a car : equal to 1, less than 1 or greater than 1, while ascending a hill ?

In a gear system, the gear ration of the driving wheel A and driven wheel B is 10:1. To rotate the driven wheel B in the direction of driving wheel A, the driving wheel A is engaged with other wheel C. what should be the gear ratio of the wheels A and C?

What is a single movable pulley? What is its mechanical advantage in the ideal case?

Name the type of single pulley that can act as a force multiplier. Draw a labelled diagram of the pulley mentioned by you.

Give two reasons why the efficiency of a single movable pulley system is not 100%.

In which direction does the force need to applied, when a single pulley is used with a mechanical advantage greater than one? How can you change the direction of force applied without altering its mechanical advantage? Draw a labelled diagram of the system.

The diagram below shows a pulley arrangement.

1. Name the pulleys A and B.
2. In the diagram, mark the direction of tension on each strand of string.
3. What is the purpose of the pulley B?
4. If the tension is T, deduce the relation between
   1. T and E, and
   2. E and L.
5. What is the velocity ratio of the arrangement?
6. Assuming that the efficiency of the system is 100%, what is the mechanical advantage?

Differentiate between a single fixed pulley and a single movable pulley.

The diagram below shows an arrangement of three pulleys A, B, and C. The load is marked as L and the effort as E.

1. Name the Pulleys A, B, and C.
2. Mark in the diagram the directions of load (L), effort (E) and tension T₁ and T₂ in the two strings.
3. How are the magnitudes of L and E related to the tension T₁?
4. Calculate the mechanical advantage and velocity ratio of the arrangement.
5. What assumptions have you made in parts (c) and (d)?

Draw a diagram of a combination of three movable pulleys and one fixed pulley to lift up a load. In the diagram, show the directions of load, effort and tension in each strand. Find:

1. mechanical advantage,
2. Velocity ratio and
3. efficiency of the combination in ideal situation.

What is a block and tackle system of pulleys?

A block and tackle pulley system has a velocity ratio 5. Draw a labelled diagram of this system.  In your diagram, indicate clearly the points of application and the directions of the load and effort.

Give reason for the following:
 In a single fixed pulley, the velocity ratio is always more than the mechanical advantage.

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.

What is the purpose of a switch in a circuit?

Give reason for the following:

The lower block of a block and tackle pulley system must be of negligible weight

A switch is not touched with wet hands while putting it on or off. Give a reason for your answer.