Here are the missing questions:
(a) How fast is the skier moving when she gets to the bottom of the hill?
(b) How much internal energy was generated in crossing the rough patch?
Part A
The initial kinetic energy of the skier is:

Part of this energy is then used to do work against the force of friction. Force of friction on the horizontal surface can be calculated using following formula:

The work is simply the force times the length:

So when the skier passes over the rough patch its energy is:

When the skier is going down the skill gravitational potential energy is transformed into the kinetic energy:

So the final energy of the skier is:

This energy is the kinetic energy of the skier:
Part B
We know that skier lost some of its kinetic energy when crossing over the rough patch. This energy is equal to the work done by the skier against the force of friction.
Answer:
Kinetic Energy
Explanation:
The potential energy is being converted into kinetic energy. The hitter has struck the ball transferring the kinetic energy from the swinging bat to the ball.
Brass, Salt and water are examples of a Homogeneous Mixture.
Answer:
Circle or pie graph is used to show how a part of something relates to the whole.
Explanation:
Pie graphs are easy to read and can present a very clear picture of the relationships.
Answer:
40 m/s due north
Explanation:
Consider that the south direction a negative Y axis and north direction as + Y axis
v1 = 20 m/s South = 20 (-j) m/s
v2 = 20 m/s North = 20 j m/s
Change in velocity = v2 - v1 = 20 j - 20 (-j) = 40 j m/s
So, change in velocity is 40 m/s due north.