Answer:
The moon has no atmosphere
Explanation:
The temperatures on the surface of the Moon vary much more than those on Earth because the moon has no atmosphere (third answer in the list), and therefore there are no molecules that could retain residual heat and make the change from day to night a softer transition.
Answer:
h = 4.04 m
Explanation:
Given that,
Mass of a child, m = 25 kg
The speed of the child at the bottom of the swing is 8.9 m/s
We need to find the height in the air is the child is able to swing. Let the height is h. Using the conservation of energy such that,

Put all the values,

So, the child is able to go at a height of 4.04 m.
When light travels from a medium with higher refractive index into a medium with lower refractive index, there is a maximum angle (called critical angle) for which all the light is reflected, so there is no refraction.
The value of the critical angle is given by:

when n1 is the refractive index of the first medium, while n2 is the refractive index of the second medium. In our case, n1=1.33 (the water) and n1=1.00 (the air). Putting numbers in, we get