Which of the following statements must be true if the net force on an object is zero? choose all that apply. a) the object must have zero acceleration. b) the object must be at the origin. c) the object must have constant velocity. d) the object must be at rest.

a & d

Explanation:

Given

Net force on object is zero i.e.

if net acceleration is zero therefore change in velocity is zero i.e. velocity is constant

It is not necessary that when an object is at rest acceleration on it is zero for example during Simple harmonic motion of spring mass system when mass is at maximum amplitude i.e. momentarily at rest then its acceleration is maximum.

this could be newton#'s law of cooling. the cooling curve is exponential

force required to detach it is given by

charges are taken to be fundamental charge

now we have

so above is the minimum distance at which it will detach