If friction is acting along the plane upwards
then in this case we will have
For equilibrium of 100 kg box on inclined plane we have

also for other side of hanging mass we have

now we have




In other case we can assume that friction will act along the plane downwards
so now in that case we will have

also we have

now we have





<em>So the range of angle will be 23.45 degree to 37 degree</em>
Answer:
3Q / 4 pi (R^3 - r^3)
Explanation:
Charge density = charge / volume
volume of a spherical shell = 
Oil leakage in aquatic areas. (fish)
Burning fuel. (Air/global warming)
Toxic waste burried in dirt (living Creatures)
Lights/Electricity (destroyes Birds migration)
Noise (migration on dolphines and other sea mammals)