Three levers X, Y and Z of equal lengths are shown in the diagram. (a) Which class of lever do these belong to? (b) Among these (X, Y or Z), which one will give the maximum mechanical advantage? Justify your answer.

Draw a block and tackle system of pulleys with velocity ratio equal to 3.

Which of the following is a class III lever? (a) Pair of scissors (b) Wheelbarrow (c) Crowbar (d) Human forearm

The velocity ratio of a block and tackle system having two pulleys, with effort applied upwards, is: (a) 1 (b) 2 (c) 3 (d) 4

A block and tackle system of pulleys has velocity ratio 4. (a) Draw a labelled diagram of the system indicating clearly, the direction of the load and the effort. (b) What is the value of the mechanical advantage of the given pulley system if it is an ideal pulley system?

(a) When does the nucleus of an atom tend to become radioactive? (b) Name a single pulley in which displacement of load and effort is not the same. (c) State one advantage of this pulley.

Meera chose to use a block and tackle system of ‘9’ pulleys instead of a single movable pulley to lift a heavy load. (a) What is the advantage of using a block and tackle system over a single movable pulley? (b) Why should she connect more number of pulleys in the upper fixed block?

Given are two pulleys. (a) Copy and complete the labelled diagram connecting the two pulleys with a tackle to obtain Velocity Ratio = 2. (b) If Load = 48 kgf and efficiency is 80% then calculate: (i) Mechanical Advantage. (ii) Effort needed to lift the load.

To lift a load of 30 kgf, Suhas uses a single fixed pulley while Radha uses a single movable pulley. The displacement of efforts in both cases is equal. In an ideal situation calculate the ratio of: (a) the efforts in the two cases. (b) the potential energy gained by the loads in the two cases. (c) the efficiencies in the two cases.

Case 1: Lata cuts a potato into two halves, using a cutter which belongs to a Class II lever. She needed effort E1. Case 2: Then she cuts one half of this potato again, but this time she needed effort E2. If E1 > E2 then: (a) In which case (1st or 2nd) was the potato closer to her hand applying the effort? (Assume normal reaction of the surface of the potato is same in both cases) (b) Give a reason for your answer in (a) above.

A metal piece of mass 5 g has thermal capacity 2.5 J K⁻¹. If the mass of the metal is tripled, then its specific heat capacity will be : (a) 7.5 J K⁻¹ (b) 2.5 J K⁻¹ (c) 1.5 J g⁻¹ K⁻¹ (d) 0.5 J g⁻¹ K⁻¹

The following figure shows a small bar magnet falling freely through a copper ring. For the observer at A, the direction of the induced current will be : (a) clockwise when magnet is above and below the ring (b) anticlockwise when magnet is above and below the ring (c) anticlockwise when magnet is above the ring and clockwise when the magnet is below the ring (d) clockwise when magnet is above the ring and anticlockwise when the magnet is below the ring