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azamat
3 years ago
8

A 60-kg woman runs up a staircase 15 m high (vertically) in 20 s.

Physics
1 answer:
erma4kov [3.2K]3 years ago
4 0

Answer:

(a) 441 W (b) 0.59 hP

Explanation:

Given that,

Mass of a woman, m = 60 kg

Height of a staircase, h = 15 m

Time, t = 20 s

(a) We need to find the power she expend. Work done per unit time is called power. It is given by :

P=\dfrac{W}{t}\\\\P=\dfrac{mgh}{t}\\\\P=\dfrac{60\times 9.8\times 15}{20}\\\\P=441\ W

( b) Since, 1 hP = 745.7 W

P = 0.59 hP

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Answer:

F'=2F

Explanation:

The Coulomb's law states that the magnitude of the electrostatic force between two charges is directly proportional to the product of the magnitudes of charges and inversely proportional to the square of the distance between them:

F=\frac{kq_1q_2}{d^2}

In this case, we have q_1'=2q_1:

F'=\frac{kq'_1q_2}{d^2}\\F'=\frac{k(2q_1)q_2}{d^2}\\F'=2\frac{kq_1q_2}{d^2}\\F'=2F

3 0
3 years ago
You have a set of calipers that can measure thicknesses of a few inches with an uncertainty of ± 0.005 inches. You measure the t
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Answer:

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Explanation:

a) The thickness of the deck of cards (d) is measured and the thickness of a card (x) is calculated

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Let's look for uncertainty

       Δx = dx /dd Δd

       Δx = 1/52 Δd

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The result of the calculation is

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b) You want to reduce the error to Δx = 0.00002, the number of cards to be measured is

           #_cards = n 52

The formula for thickness is

           x = d / n 52

Uncertainty

          Δx = 1 / n 52  Δd

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         n = 1/52 0.005 / 0.00002

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Since the number of decks must be an integer the number of decks is 5

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4 years ago
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F = mg
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m = 4.00 kg

Hope this answers the question. Have a nice day.
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4 years ago
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The photon can be absorbed and the energy of the photon is exactly equal to the energy-level difference between the ground state and the level d.

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