The power expended is 500 W
Explanation:
First of all, we start by calculating the work done by the man in order to ascend: this is equal to the gravitational potential energy gained by the man, which is

where
m = 50 kg is the mass of the man
is the acceleration of gravity
is the change in height
Substituting,

Now we can calculate the power expended, which is given by

where
W = 2500 J is the work done
t = 5 s is the time elapsed
Substituting, we find

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Answer:
Friction or tension
Explanation:
Friction stops an object from moving in the presence of force
Answer:
A: T = 120 N
B: T = 88.42 N
C: T = 70 N
Explanation:
Part A:
Since, the lighter bucket is supported by my had. So, the only unbalanced force in the system is the weight of heavier bucket. Hence, the tension in rope will be equal to the weight of heavier bucket.
<u>T = 120 N</u>
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Part B:
This is the case where, two masses hang vertically on both sides of the pulley. To find the tension in such case we have the formula:
T = (2 m₁m₂g)/(m₁+m₂)
where,
m₁ = mass of heavier object = W₁/g = (120 N)/(9.8 m/s²) = 12.24 kg
m₁ = mass of lighter object = W₂/g = (70 N)/(9.8 m/s²) = 7.14 kg
g = 9.8 m/s²
Therefore,
T = [(2)(12.24 kg)(7.14 kg)(9.8 m/s²)]/(12.24kg + 7.14 kg)
T = 1713.6 N.kg/19.38 kg
<u>T = 88.42 N</u>
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Part C:
Since, the heavier bucket is on ground. So, its weight is balanced by the normal reaction of the ground. The only unbalanced force in the system is the weight of lighter bucket. Hence, the tension in rope will be equal to the weight of lighter bucket.
<u>T = 70 N</u>
Atomic structure applies to just that, atoms in isolation. Witness looking at atomic spectra using laboratory discharge tubes to ionise low pressure gases of atoms of the elements you want to examine for energy level structure (sodium and the yellow D line "doublet").Crystal structure applies to vast collections of atoms/molecules/ions in complicated geometrical arrays which form lattices. Simple cubic, body centred cubic, face centred cubic being a few "simple" examples.