The following MCQ which appeared in the IIT-JEE question paper is interesting:

(a) Fa/2m

**√(a**

^{2}**–x**

^{2})^{}(b) Fx/2m√(a^{2}–x^{2})^{}(c)

**Fx/2ma (d) F√(a**

^{2}**–x**

^{2}) /2mx^{}The horizontal force on each particle is T cosθ = Fcosθ/2sinθ = F/2tanθ.

Therefore, the magnitude of acceleration of each particle is given by

acceleration = force/mass = F/(2m tanθ) = F/[2m√(a^{2}–x^{2})/x] = Fx/2m√(a^{2}–x^{2})** **^{}

The following Assertion-Reason Type Multiple Choice Question also appeared in the IIT-JEE 2007 question paper:

**STATEMENT-1**

**A cloth covers a table. Some dishes are kept on it. The cloth can be pulled out without dislodging the dishes from the table**

*because *

**STATEMENT-2**

**For every action there is an equal and opposite reaction.**

**(a) Statement-1 is True, Statement-2 is True; Statement-2 is a correct ****explanation for Statement-1**

**(b) Statement-1 is True, Statement-2 is True; Statement-2 is NOT a correct ****explanation for Statement-1**

**(c) Statement-1 is True, Statement-2 is False**

**(d) ****Statement-1 is False, Statement-2 is True**** **

This is a simple question which you can answer in no time if you have understood the property of inertia. In fact, by repetition this question has become a ‘knowledge’ type even though it is supposed to be an ‘understanding and application’ type.

If you pull the cloth out abruptly in the horizontal direction, the dishes will remain intact on the table. Because of inertia, the dishes cannot move sideways immediately and will touch the bare surface of the table where they will rest as before.

Statement-2 is Newton’s third law which is not the reason for statement-1.

So, the correct option is (b).

thank u so much...

ReplyDeleteThank you sir for sharing such illustration.

ReplyDelete