Answer: Physical changes in nature could then be erosion in a mountain, the melting of snow, and a river freezing over from the cold. Since none of these changes affect the chemical composition of the mountain, the snow, or the river, they are physical changes.
Explanation:
Yes, it is <span>accurate to describe the physical universe as composed of only matter and energy. Some people might argue about the dark matter, but it is not yet defined properly. Different universes can be made up of different compositions but it is a fact that our universe is made of matter and energy. </span>
Answer:
v = √2G 
/ R
Explanation:
For this problem we use energy conservation, the energy initiated is potential and kinetic and the final energy is only potential (infinite r)
Eo = K + U = ½ m1 v² - G m1 m2 / r1
Ef = - G m1 m2 / r2
When the body is at a distance R> Re, for the furthest point (r2) let's call it Rinf
Eo = Ef
½ m1v² - G m1 / R = - G m1 / R
v² = 2G (1 / R - 1 / Rinf)
If we do Rinf = infinity 1 / Rinf = 0
v = √2G / R
Ef = = - G m1 m2 / R
The mechanical energy is conserved
Em = -G m1 / R
Em = - G m1 / R
R = int ⇒ Em = 0
Answer:
Convection occurs when thermal energy is transferred by the movement of fluid particles.
Explanation:
Transfer of heat energy by the movement of fluid particles is called convection. Convection takes place in liquids and gases due to kinetic energy. When heat is provided to liquids and gases they expand and move faster.
Molecules with higher kinetic energy become less dense and rise up to the surface of liquid, whereas molecules with lower energy move towards the bottom. This up and down movement of molecules causes convection currents in fluids.
Two atoms of the element bind to form dinitrogen and it’s a colourless and odorless diatomic gas with the formula N2. Also Dinitrogen forms up about 78% of earths atmosphere
