Answer:
Part a)

Part b)

Part c)

Part d)

Part e)

Part f)

Explanation:
As we know that initial velocity of the ball is given as


Now final velocity of the system is given as

Part a)
now magnitude of initial momentum is given as



Part b)
Change in momentum is given as



Part c)
As we know that average force is defined as the rate of change in momentum
so here we have



Part d)
Magnitude of change in momentum is given as



Part e)
As we know that in 2nd case the force is same as the initial force
so we will have



Part f)
Since this is elastic collision so change in kinetic energy must be ZERO

Answer:
1. Nitrogen
2. Oxygen
3. Carbon dioxide
4. Water vapor
5. Ozone
Explanation:
The atmosphere composes of 78% nitrogen which occupies the largest percentage followed by oxygen which takes up 21%, Argon takes up 1% then other components such as water vapor occupy between 0-7% and ozone takes 0.0-0.01. Moreover, 0.01-0.1 is occupied by carbon dioxide. Therefore, the answers for 1-5 are as follows.
1. Nitrogen
2. Oxygen
3. Carbon dioxide
4. Water vapor
5. Ozone
Answer:
I assume they want answer A, but it's a silly question.
Explanation:
Well, if we assume that the girls are applying equal force, as they are the same size and strength (apparently also the same resolve etc.).
Equal force in opposite directions means the composite force is null. An object that no force is applied to continues moving in the same direction, so if the doll was moving somewhere, it would keep doing so, except all of this makes no sense the doll is not in gravityless vacuum what are we even talking about.
The answer A is the least ridiculous.