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2 years ago

Marvin lifts a box over his head. The work done on the box is- -Negative work -No work -Positive work

Physics

1 answer:

NemiM [27]2 years ago

6 0

Answer:

Positive work

Explanation:

When work and the exerted force are in the same direction, then the work done is positive.

In the question, we understand that Marvin lifts a box up (i.e. over his head). The force to lift the box acts in the upward direction and the work done itself is also in the upward direction (from the floor to Marvin's head).

Since these two are in the same direction, then we can conclude that the work done is positive.

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Shah did not trust the results of an experiment that she had read about, so she is conducting the experiment herself. She goes t

Hitman42 [59]

The question is incomplete, the complete question is;

Shah did not trust the results of an experiment that she had read about, so she is conducting the experiment herself. She goes through the same set of steps and measures the effect of the amount of sugar on a single organism.

Which best describes what Shah is doing?

replication

repetition

both repetition and replication

neither repetition nor replication

Answer:

replication

Explanation:

Replication in scientific experiments refer to the process of going through all the steps in an experiment in order to obtain the same set of results initially obtained.

All scientific experiments is expected to be replicated under identical experimental conditions. If the results obtained by a scientific investigation cannot be replicated under identical circumstances by other scientists, then the scientific data must be taken with a pinch of salt.

Shah is expected to obtain almost exactly the same data as the original researchers who first published the data.

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3 years ago

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What is the relationship between karst development and topography?

mylen [45]

The karst topography is typically defined as a geographic location characterized by a rugged terrain containing landscapes like underground rivers, fissures, and cracks. It is mainly due to the dissolution of the bedrock due to a much heavier precipitation taking place in the geographic location.

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3 years ago

Tp-18 what should you do when operating a boat in large waves and high wind?

deff fn [24]

1) Try to head into the waves at some slight angle and the speed of the boat should be reduced.

2) In order to ride up and over the waves, the speed of the boat should be slow.

3) The less the speed of the boat, and the less strain will be put on the hull and superstructure.

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3 years ago

How many photons will be required to raise the temperature of 1.8 g of water by 2.5 k ?'?

tatyana61 [14]

Missing part in the text of the problem:
"<span>Water is exposed to infrared radiation of wavelength 3.0×10^−6 m"</span>

First we can calculate the amount of energy needed to raise the temperature of the water, which is given by
$Q=m C_s \Delta T$
where
m=1.8 g is the mass of the water
$C_s = 4.18 J/(g K)$ is the specific heat capacity of the water
$\Delta T=2.5 K$ is the increase in temperature.

Substituting the data, we find
$Q=(1.8 g)(4.18 J/(gK))(2.5 K)=18.8 J=E$

We know that each photon carries an energy of
$E_1 = hf$
where h is the Planck constant and f the frequency of the photon. Using the wavelength, we can find the photon frequency:
$\lambda = \frac{c}{f}= \frac{3 \cdot 10^8 m/s}{3 \cdot 10^{-6} m}=1 \cdot 10^{14}Hz$

So, the energy of a single photon of this frequency is
$E_1 = hf =(6.6 \cdot 10^{-34} J)(1 \cdot 10^{14} Hz)=6.6 \cdot 10^{-20} J$

and the number of photons needed is the total energy needed divided by the energy of a single photon:
$N= \frac{E}{E_1}= \frac{18.8 J}{6.6 \cdot 10^{-20} J} =2.84 \cdot 10^{20} photons$

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3 years ago

Which option describes the direction of thermal energy transfer in Earth's

Montano1993 [528]

.........

Explanation:

Option B..... ...

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3 years ago

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