The law<span> of conservation of </span><span>energy.</span>
Answer:
Since F = G * m1 * m2 / r^2
F = 6.67 * 19E-11 * 2.79 * 9.47 * 10E23 / (1.2 * 10^7)^2
F = 126 * 10E-2 N = 1.22 N
Answer:
The correct answer is option 'c': 30 AUs
Explanation:
For a spherical wave front emitted by sun with total energy 'E' the energy density over the surface when it is at a distance 'r' from the sun is given by
This energy per unit area is sensed by observer as intensity of the sun.
Let the initial intensity of sun at a distance 
be 
Thus if the sun becomes 900 times dimmer we have
Thus the distance increases 30 times.
Answer:
This is because below 4°c, water unlike other materials becomes less dense when it's temperature is further lowered.
Explanation:
Due to the unusual nature of water; at about 4°c, the behavior of the density of water in relation to its temperature reverses. This means that water becomes less dense as it becomes colder below 4°c. The colder parts therefore floats to the top of the water body while the warmer part sinks allowing the top to freeze and the remaining body below to remain in its liquid state.
The freezing of the top of the lake alone protects the remaining depth of water from freezing by acting as an insulator and preventing further heat loss from the water to the ambient space. If this had not been the case, and water froze all through, marine lives will freeze to death and it will be more difficult to melt the ice come the next summer.
This behavior is due to the hydrogen bonding of the water molecules.
