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← JEE Main 2022 · 28 Jul · Shift 2
PhysicsInteger+4 / -1Question 22 of 90

JEE Main 2022 · 28 Jul · Shift 2, Physics question 22

The distance of centre of mass from end A of a one dimensional rod (AB) having mass density ρ=ρ0(1−x2L2)\rho=\rho_0\left(1-\dfrac{x^2}{L^2}\right) kg/m and length L (in meter) is 3Lα\dfrac{3L}\alpha m. The value of α\alpha is ______. (where xx is the distance from end A)

Answer and worked solution

Official answer: 8

Centre of mass. ∫ρx dx=ρ0L24\int\rho x\,dx=\frac{\rho_0L^2}4 and ∫ρ dx=2ρ0L3\int\rho\,dx=\frac{2\rho_0L}3, so xcm=3L8x_{cm}=\frac{3L}8.

Answer: 8