In which of the following cases, the centre of mass of a rod is certainly not at its centre?
a. The density increases from left to right up to the centre and then decrease
b. The density decreases from left to right up to the centre and then increase
c. The density continuously increases from left to right
d. The density continuously decreases from left to right
Choose the correct alternative:
(a) Acceleration due to gravity increases/decreases with increasing altitude.
(b) Acceleration due to gravity increases/decreases with increasing depth. (assume the earth to be a sphere of uniform density).
(c) Acceleration due to gravity is independent of mass of the earth/mass of the body.
(d) The formula āG Mm(1/r2ā 1/r1) is more/less accurate than the formula mg(r2ā r1) for the difference of potential energy between two points r2and r1distance away from the centre of the earth.