List of top Physics Questions on Simple Machines

Case 1: Lata cuts a potato into two halves, using a cutter which belongs to a Class II lever. She needed effort E\(_1\).
Case 2: Then she cuts one half of this potato again, but this time she needed effort E\(_2\).
If E\(_1\) > E\(_2\) 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.
The reverse side of a three-pin plug with incorrect connection of wires is shown in the diagram below.
(a) Identify the fault in the above connection.
(b) Mention a risk factor involved, if the user operates the appliance with correcting it.
(c) Will the appliance function in the present situation? (Yes or No)
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 the cases are 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.
The energy transformation taking place during photosynthesis in plants is:
To which class of lever does a pair of scissors belong?