Question

1. a metallic bar has a mass 200g at poles, does it change when taken to equator?
2. does its weight change when brought to equator? if yes, how?
3. where on earth will the weight be zero ?

Answer 1

1. no it will not change it mass
2. yes as earth is not perfectly round poles are flat at top so value of g will be change in equator and poles hence; weight = mass * g so the weight change
3. at the centre of earth

Answer 2

1. Mass remains same through out the universe.so at poles and equator mass 200g will not change.

2. Weight=mg
where as g depends on radius of earth
gα1/R
as Radius at equator is more, g value decreases  so weight at equator also decreases.

as Radius at poles is minimum, so g value increases . So weight at poles increases.

3.When the object is at the centre of earth , g will be zero. Hence weight of the object at the centre of earth will be zero.