Answer:
Kepler's first law means that planets move around the Sun in elliptical orbits. An ellipse is a shape that resembles a flattened circle. ... It is zero for a perfect circle.
Since you already gave us the weight of the 2.5-kg box,
we don't even need to know what the distance is, just
as long as it doesn't change.
Look at the formula for the gravitational force:
F = G m₁ m₂ / R² .
If 'G', 'm₁' (mass of the Earth), and 'R' (distance from the Earth's center)
don't change, then the Force is proportional to m₂ ... mass of the box,
and you can write a simple proportion:
(6.1 N) / (2.5 kg) = (F) / (1 kg)
Cross-multiply: (6.1 N) (1 kg) = (F) (2.5 kg)
Divide each side by (2.5 kg): F = (6.1N) x (1 kg) / (2.5 kg) = 2.44 N .
Physics- damon, Monday, December 1, 2014 at 3:27 pm force =change in momentum\ change in time or m a if m is constant
change in momentum/3=200
change in momentum =3*200 kg m/s
Answer:

Explanation:
The charge on one object, 
The distance between the charges, r = 0.22 m
The force between the charges, F = 4,550 N
Let q₂ is the charge on the other sphere. The electrostatic force between two charges is given by the formula as follows :

So, the charge on the other sphere is
.
I beleive she isnt doing any work due to holding the box motionless, you must be exerting a force in the direction of the box motion. If she is just standing there holding the box their isn't no work becuase no distance has been covered. work = force = distance.