Hello!
a) Assuming this is asking for the minimum speed for the rock to make the full circle, we must find the minimum speed necessary for the rock to continue moving in a circular path when it's at the top of the circle.
At the top of the circle, we have:
- Force of gravity (downward)
*Although the rock is still connected to the string, if the rock is swinging at the minimum speed required, there will be no tension in the string.
Therefore, only the force of gravity produces the net centripetal force:

We can simplify and rearrange the equation to solve for 'v'.

Plugging in values:

b)
Let's do a summation of forces at the bottom of the swing. We have:
- Force due to gravity (downward, -)
- Tension force (upward, +)
The sum of these forces produces a centripetal force, upward (+).

Rearranging for 'T":

Plugging in the appropriate values:

Spherical because it’s more like clouds
I don't understand this question
Answer:
An increase in pressure
Explanation:
The ideal gas law states that:

where
p is the gas pressure
V is the volume
n is the number of moles
R is the gas constant
T is the temperature of the gas
in the equation, n and R are constant. For a gas kept at constant volume, V is constant as well. Therefore, from the formula we see that if the temperature (T) is increase, the pressure (p) must increase as well.