These two cubes represent a small cell and large cell .
1 answer:
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Answer:
k = 104.5 N/m
Explanation:
When she reaches the lowest point the velocity of the jumper is 0. This means all her kinetic energy has been absorbed by the cord.
The energy absorbed by a spring (a cord can be treated as a spring when it's being stretched) is:
Where:
Ee = elastic potential energy
k = elastic constant
Δx = lenght the spring was stretched
When a body falls, it's potential gravitational energy is converted to kinetic energy. So the kinetic energy of a body can be calculated as the gravitational potential energy it lost.
The gravitational potential energy is:
Where:
Ep: potential gravitational energy
m: mass
g: acceleration of gravity
Δh: change of height (final - initial)
When she has fallen 31 m she has lost
62 kg * 9.81 m/s^2 * 31 m = 18854 J
Since her velocity at the bottom is 0, her kinetic energy is 0 J.
All her kinetic energy has been absorbed by the cord and transformed into elastic potential energy. So we can equate these two energies.
Ep = Ee
Then:
Δx = 31 m - 12 m = 19 m
From here the only unknown is k:
To develop the problem it is necessary to take into account the concepts related to Torque and sum of moments.
By torque it is understood that
Where,
F= Force
d = Distance
The value of the given Torque acts from the center of mass causing it to rotate clockwise.
The Force must then be located at the other end down to make a movement opposite the Torque in the center of mass.
I enclose a graph that allows us to understand the problem in a more didactic way.
The correct answer is D.
