A force of - P k ^ acts on the origin of the coordinate system. The torque about the point ( 2 , - 3 ) is P…

A force of -Pk^ acts on the origin of the coordinate system. The torque about the point (2,-3) is P(ai^+bj^), The ratio of ab is x2. The value of x is

Solution

It is given that the force F=-Pk^

The coordinates of the origin is (0,0).

The coordinates of the point given is  (2,-3)

The displacement vector is 

r=(0-2)i^+(0+3)j^=-2i^+3j^

Hence, the torque is 

τ=r×F=(-2i^+3j^)×(-Pk^)

τ=-2Pj^-3Pi^=P(ai^+bj^)

So, it can be written

a=-3b=-2

  ab=32 so x=3

Asked in: JEE Main 2023 (10 Apr Shift 2)

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