Answer: A) 
Explanation:
The equation for the moment of inertia 
of a sphere is:
(1)
Where:
is the moment of inertia of the planet (assumed with the shape of a sphere)
is the mass of the planet
is the radius of the planet
Isolating from (1):
(2)
Solving:
(3)
Finally:
Therefore, the correct option is A.
Answer:
20.2 seconds
Explanation:
The airplane (and therefore the crate) initially has no vertical velocity, so v₀ = 0 m/s.
The crate is in free fall, so a = -9.8 m/s².
The crate falls downward, so Δx = -2000 m.
Find: t, the time it takes for the crate to land.
Δx = v₀ t + ½ at²
-2000 m = (0 m/s) t + ½ (-9.8 m/s²) t²
t = 20.2 s
It takes 20.2 seconds for the crate to land.
The correct answer is
B It increases.
In fact, the kinetic energy of a moving object is given by
where m is the mass of the object and v is its speed. We see that the kinetic energy is proportional to the mass and proportional to the square of the speed: in this problem, the speed of the object remains the same, while its mass increases, therefore the kinetic energy will increase as well.
Answer:
2 miles
Explanation:
Jimmy walked forward 3 miles east (to the right)
Then, he backtracked and walked 1 mile west (to the left)
This can be written as:
3 - 1 = ?
3 - 1 = 2
Therefore, Jimmy traveled a total of 2 miles.
Answer:
129.2 C
0.33758239177 mm
Explanation:
n = Number density = 
i = Current = 170 A
t = Time taken = 0.76 s
d = Diameter = 6 mm
Charge is given by
The charge passing throught the motor is 129.2 C
Current density
Drift velocity is given by
Distance traveled
The electron traveled 0.33758239177 mm
