question_answer

The coordinates of centre of mass of a uniform Flag shaped lamina (thin flat plate) of mass 4 kg. (The coordinates of the same are shown in figure) are [JEE MAIN Held On 08-01-2020 Morning]

A) \[\left( 0.75\text{ }m,\text{ }1.75\text{ }m \right)\]

B) \[\left( 1.25\text{ }m,\text{ }1.50\text{ }m \right)\]

C) \[\left( 1\text{ }m,\text{ }1.75\text{ }m \right)\]

D) \[\left( 0.75\text{ }m,\text{ }0.75\text{ }m \right)\]

Correct Answer: A

Solution :

For given Lamina \[{{A}_{1}}=1,\text{ }{{C}_{1}}=\left( 1.5,\text{ }2.5 \right)\] \[{{A}_{2}}=3,\text{ }{{C}_{2}}=\left( 0.5,\text{ }1.5 \right)\] \[\therefore {{X}_{cm}}=\frac{1.5+1.5}{4}=0.75\] \[{{Y}_{cm}}=\frac{2.5+4.5}{4}=0.75\] \[\therefore \] Coordinate of centre of mass (0.75, 1.75)