Answer:
The first law of thermodynamics, also known as Law of Conservation of Energy, states that energy can neither be created nor destroyed; energy can only be transferred or changed from one form to another. For example, turning on a light would seem to produce energy; however, it is electrical energy that is converted. Nothing happens to the energy. It does not change form, since energy has no form. ... If the energy was moving, it gets stored or re-transmitted elsewhere. Using energy means controlling its movement, rather than consuming it.
Answer:
A. velocity has a direction .. .
with magnitude too but speed has only magnitude
Answer:
M V R = constant angular momentum is constant because no forces act in the direction of V
Since M (mass) = constant
V R = constant
The force is directed along the gravitational force vector (towards the center of rotation)
First we gotta use an equation of motion:

Our vertical distance d= 100 m, initial vertical speed u = 0 m/s (because velocity is fully horizontal), and vertical acceleration a = 9.8 m/s2 because of gravity. Let's plug it all in!

Now we just need to solve for t:

Hit the calculators, and you'll get 4.5 seconds!
Whenever a net force acts on an object, it means object is under acceleration which implies that there is change in the object's velocity.