The weight of a body on a planet is 100 N. If planet's radius is half and density same as Earth, weight becomes MCQ with Answer and Explanation

Explanation:
On a frictionless surface, no net external force is required to maintain uniform velocity (Newton's first law). Only to change velocity force is needed. Thus, force required is zero. If friction present, force would be needed to balance friction.

Explanation:
By definition, a force is conservative if the work done by it on an object moving between two points is completely independent of the path taken. A direct consequence of this is that the total work done by a conservative force (like gravity or electrostatic force) in moving an object around a closed loop (returning to the starting point) is exactly zero.

Explanation:
J.J. Thomson proposed plum-pudding: positive sphere with embedded electrons. Rutherford disproved by gold foil experiment, proposed nuclear model. Bohr added energy levels. Dalton solid sphere.