5
2 answers:
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Answer:
Explanation:
The energy lost due to air friction is equal to the mechanical energy lost by the parachutist during the fall.
The initial mechanical energy of the parachutist (at the top) is equal to his gravitational potential energy:
where
m = 20.1 kg is his mass
is the acceleration due to gravity
h = 662 m is the initial heigth
The final mechanical energy (at the bottom) is equal to his kinetic energy:
where
v = 7.12 m/s is the final speed of the parachutist
Therefore, the energy lost due to air friction is:
Answer:
B) approaches infinity
Explanation:
The capacitive reactance of an AC capacitor is given by;
Where;
C is the capacitance
f is the frequency of the ac voltage
Therefore, as the frequency of the ac voltage across a capacitor approaches zero, the capacitive reactance of that capacitor approaches infinity.
The correct option is (B) approaches infinity
Answer:
AB = 29
Explanation:
For a better understanding, we must work this problem in a graphic way. In the attached image we can see the solution.
First, we draw a vertical dotted lines from the point J & K to the line ML, then we can see two new portions with the same length. Then with this simple analysis:
2x = 39 - 19
x = 10
Then we know that x = 10, another important data to find the answer is that the AB line is located in the midpoints of the legs. We also can see the right triangle MJ and the dotted line.
Now for every single right triangle, no matter its size and relationship between the vertical and the horizontal lengths, if some point is located in the hypotenuse (leg) at the middle of its length. This will be proportional to the vertical and the horizontal cathetus, therefore we will have the middle point on those two lines.
So, the AB line will be the sum of JK plus two times 5
AB = 19 + 5 + 5 = 29
