A man weighs 90 N on the surface of earth of radius R at what height above the surface of earth is weight will be 40 N.

3/2 R

Explanation:

Let the Mass of man be m, Mass of earth be M.

By Newtons, law of gravitation,

F = GMm/R^2, Where G is gravitational constant

90 = GMm/R^2

When man weighs 40N,

GMm/(New R)^2 = 40

= 4/9 (90)

GMm/(New R)^2 = 4/9 (GMm/R^2)

(New R)^2 = 9/4 R^2

New R = 3/2 R

Therefore, height is 3/2 R

need to see circuit to get time constant

hi there!

out of the two, (b) precision would be more reasonable.   however, both a and b could be pretty reasonable.

-awesomerepublic   : )