A straight rod of length L extends from x = a to x = L+ a. If the linear density of rod is μ = A + Bx², then the gravitational force exerted by rod on a particle of mass m at x = 0 is:

Q: A straight rod of length L extends from x = a to x = L+ a. If the linear density of rod is μ = A + Bx², then the gravitational force exerted by rod on a particle of mass m at x = 0 is:

(a) $G m (B L – \frac{A}{a})$

(b) $G m (B L + \frac{A}{a})$

(c) $G m [B L + A(1- \frac{1}{a+L})]$

(d) $G m [B L + A(\frac{1}{a} – \frac{1}{a+L})]$

Ans: (d)