Tutor profile: Pankaj K.
Subject: Physics (Newtonian Mechanics)
Does your weight read by an weighing machine get changed when you are in a lift going up or down with some acceleration? What is pseudo force and where it is used?
Yes, weight read by machine get changed and the reading can be guessed if you have clear idea of solving such problems in accelerating frame (i.e. non-inertial frame). Pseudo force is a fake force which is used to apply Newton’s laws of motion in non-inertial frame of reference. There are many interesting problems which get simplified when we approach them from non inertial frame of reference.
Subject: Physics (Electricity and Magnetism)
Can you charge two conducting body by rubbing each other?
No. By rubbing we generate frictional electricity, which is possible only when there is at least one non-conducting body. In frictional electricity there is transfer of electrons from one body to another which causes a potential difference between the two bodies. If both bodies are conducting (i.e. having free electrons and motion of charges throughout the body) then before leaving the contact electrons will move back to its original body because of potential of potential difference and feasibility of movement of charges. If one is non-conducting then in that charges just get embedded, there is no scope of motion of charges so that can store charge.
What will the effect on duration of day&night when number of high rise buildings increases? (Based of Newtonian Classical Physics- Mechanics)
It is going to increase. With the concept of Rotational Mechanics, when more high rise building are made, the Moment of Inertia of the Earth ( considering it a solid sphere) will increase. And by conservation of angular momentum ( moment of inertia* angular velocity=constant) angular velocity will decrease, and since angular velocity is inversely related to time period thus time period will increase.
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