Answer:
The velocity of the blades is 88.185 m/s.
Explanation:
Given;
length of the blade, r = 80 m
angular speed, ω = 1 rev per 5.7 seconds
The velocity of the blades is calculated by applying the following circular motion equation that relates linear velocity (V) and angular speed (ω);

Therefore, the velocity of the blades is 88.185 m/s.
1) The mass of the continent is 
2) The kinetic energy of the continent is 1683 J
3) The speed of the jogger must be 6.57 m/s
Explanation:
1)
The continent can be represented as a slab of size

and depth

So its volume is

We also know that the density of the continent is

Therefore, we can calculate its mass as:

2)
The kinetic energy of the continent is given by

where
m is its mass
v is its speed
We have already calculate its mass, while the speed is
v = 3.2 cm/year
We have to convert into SI units first, as follows:

The mass is

So, the kinetic energy of the continent is

3)
Here we have a jogger having the same kinetic energy of the continent, so

And the kinetic energy of the jogger can be expressed as

where
m = 78 kg is the mass of the jogger
v is his speed
We can therefore re-arrange the equation to find the speed of the man, and we get:

Learn more about kinetic energy:
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Answer:
d) 0 V
Explanation:
It can be showed that the potential due to a point charge q, to a distance d from the charge, can be expressed as follows:

where k = 
As the potential is an scalar, and is linear with the charge, we can apply the superposition principle, which means that we can find the potential due to one of the charges, as if the other were not present.
By symmetry, all four charges are at the same distance from the center, so we can write the total potential, as follows:

where d, is the semi-diagonal of the square, that we can find applying Pythagorean theorem, as follows:

Replacing by the values in (1) we have:

which is equal to the option d).
Answer:
10.45m/s^2
Explanation:
Cause acceleration is the force divided by the mass
Answer:
4.825 N
Explanation:
mass of earth. Me = 6 x 10^24 kg
mass of moon, Mm = 7.34 x 10^22 kg
Mass of satellite, Ms = 1250 kg
length of side of triangle, a = 3.84 x 10^5 km = 3.84 x 10^8 m
A.
force on space craft by the earth

By substituting the values

F1 = 3.39 N
force on space craft by the moon

By substituting the values

F2 = 0.042 N
These two forces act at 60° with each other


F = 4.825 N