a) many people think that no energy or matter exists outside the universe.
An isolated system is defined as a system that does not interact with its surroundings. This is the reason that its total energy and mass remains constant. Moreover, t<span>otal</span><span> momentum in a system is conserved for collisions occurring in </span><span>isolated systems.</span>
The Earth's atmosphere is kept close to Earth by gravity. Just as the Earth's gravity keeps you firmly on the ground, it also acts on the gases of the Earth's atmosphere, holding it in place and allowing us to breathe.
According to the formula
Where a is work, f is force and d is the distance that box was moved over. And from that formula, you can get that f = a/d and that is 54.83N of force
Such system is called RADAR (<span>RAdio </span>Detection<span> And Ranging).
The Radar emits radio waves, that are reflected back by the object. Since the speed of the radio waves is known (their speed is equal to the speed of light), by measuring the time the waves take to come back to the source it is possible to infer the distance they covered, and so the distance of the object.</span>
Distance= speed (multiplied by) time
