Being made mostly of gas is NOT a
characteristic of an inner planet. The correct answer between all the choices
given is the last choice or letter D. I am hoping that this answer has
satisfied your query and it will be able to help you in your endeavor, and if
you would like, feel free to ask another question.
Answers:
a) 30 m/s
b) 480 N
Explanation:
The rest of the question is written below:
a. What is the final speed of the falcon and pigeon?
b. What is the average force on the pigeon during the impact?
<h3>a) Final speed</h3>
This part can be solved by the Conservation of linear momentum principle, which establishes the initial momentum 
before the collision must be equal to the final momentum 
after the collision:
(1)
Being:
Where:
the mas of the peregrine falcon
the initial speed of the falcon
is the mass of the pigeon
the initial speed of the pigeon (at rest)
the final speed of the system falcon-pigeon
Then:
(2)
Finding :
(3)
(4)
(5) This is the final speed
<h3>b) Force on the pigeon</h3>
In this part we will use the following equation:
(6)
Where:
is the force exerted on the pigeon
is the time
is the pigeon's change in momentum
Then:
(7)
(8) Since 
Substituting (8) in (6):
(9)
(10)
Finally:
In order to completely describe a velocity,
you need a speed and a direction.
<span>Let F be the force of gravity, G be the gravitational constant, M be the mass of the earth, m your mass and r the radius of the earth, then:
F = G(Mm / (4(pi)*r^2))
The above expression gives the force that you feel on the earth's surface, as it is today!
Let us now double the mass of the earth and decrease its diameter to half its original size.
This is the same as replacing M with 2M and r with r/2.
Now the gravitational force (F' ) on the new earth's surface is given by:
F' = G(2Mm / (4(pi)(r/2)^2)) = 2G(Mm / ((1/4)*4(pi)*r^2)) = 8G(Mm / (4(pi)*r^2)) = 8F
So:
F' = 8F
This implies that the force that you would feel pulling you down (your weight) would increase by 800%!
You would be 8 times heavier on this "new" earth!</span>
