Copernicus believed the planetary motions were due to: circular heliocentric orbits elliptical heliocentric orbits elliptical geocentric orbits circular geocentric orbits​

How many neutrons does element x if it’s atomic number is 28 and its mass number is 87

Global climatic patterns are changing because of the melting of polar ice caps. the melting of polar ice caps is an example of the interaction between the atmosphere and cryosphere cryosphere and geosphere hydrosphere and geosphere biosphere and cryosphere

1. explain how you calculate the net force in any direction on the box. 2. suppose an upward force of 15n is added to the box. what will be the net vertical force on the box? 3. what force could be applied to the box to make the net force in the horizontal direction zero? explain. 4. suppose a force of 25n to the right is added to the box. what will be the net force to the right?