The answer would be:
C. An unbalanced force has acted on the vehicle.
The presence of an unbalanced force will accelerate an object, the second law of motion dictates this (Although not explicitly). Lets knock out the rest of the choices.
If a balance force acted on the vehicle, then the vehicle would be at rest. The mass of the vehicle did not change (Unless it falls apart, which I doubt). The direction of the vehicle does not change and it will only do so if another force and a stronger one at that will counteract the current net force acting on the vehicle.
Hope you got your answer here, although you did not ask for an explanation, maybe this will help you figure some of the other questions you have on your own.
Well first of all, you must realize that it depends on how the jumpers are distributed on the earth's surface. If,say, one billion of them are in the eastern hemisphere and the other billion are in the western one, then the sum of all of their momenta could easily be zero, and have no effect at all on the planet. I'm pretty sure what you must have in mind is to consider the Earth to be a block, with a flat upper surface, and all the people jump in the same direction.
average mass per person = 60 kg.
jump velocity = 7 m/s straight up and away from the block, all in the same direction
one person's worth of momentum = (m) (v) = 420 kg.m/s
sum of two billion of them = 8.4 x 10¹¹ kg-m/s all in the same direction
Earth's "recoil" momentum = 8.4 x 10¹¹ in the opposite direction = (m) (v)
Divide each side by 'm' : v = (momentum) / (mass) =
The Earth's "recoil" velocity is (8.4 x 10¹¹) / (5.98 x 10²⁴) =
1.405 x 10⁻¹³ m/s =
<em> 0.00000000014 millimeter per second
</em>I have no intuitive feeling for this kind of thing, so can't judge whether
the answer is reasonable. But my math and physics felt OK on the
way to the solution, so that's my answer and I'm sticking to it.
Answer:
Very hot during the day and very cold at night.
Explanation:
Due to the thin atmosphere, they have very hot climate during the day time and very cold climate at night. This happens because they contain very low amounts of greenhouse gases. These gases retain the heat at night. The atmosphere also prevents excessive light and UV rays from entering. The thin atmosphere leads to many asteroids and comets hitting the surface of the planet. On earth, these asteroids usually, burn up in the mesosphere layer of the atmosphere. These asteroid collisions cause massive fires. This in turn, causes the temperature to increase during the day. During the night time, massive fires cannot burn due to the low temperature because of the lack of greenhouse gases.
