PLEASE help with this question!

Sam moves a box with a with a force of 400N a distance of 5 meters. How long did it take him to move the box if 20 Watts of powe

Vlad1618 [11]

Answer:

100s

Explanation:

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4 0

2 years ago

Read 2 more answers

A power plant running at 39 % efficiency generates 330 MW of electric power. Part A At what rate (in MW) is heat energy exhauste

marusya05 [52]

516.154 megawatts of heat are exhausted to the river that cools the plant.

By definition of energy efficiency, we derive an expression for the energy rate exhausted to the river ( $Q_{out}$ ), in megawatts:

$Q_{out} = Q_{in} - W$

$Q_{out} = \left(\frac{1}{\eta}-1 \right)\cdot W$ (1)

Where:

$\eta$ - Efficiency.
$W$ - Electric power, in megawatts.

If we know that $\eta = 0.39$ and $W = 330\,MW$ , then the energy rate exhausted to the river is:

$Q_{out} = \left(\frac{1}{0.39}-1 \right)\cdot (330\,MW)$

$Q_{out} = 516.154\,MW$

516.154 megawatts of heat are exhausted to the river that cools the plant.

We kindly to check this question on first law of thermodynamics: brainly.com/question/3808473

7 0

2 years ago

A wheel is rotating freely at angular speed 420 rev/min on a shaft whose rotational inertia is negligible. A second wheel, initi

Mashcka [7]

Answer:60 rev/min

Explanation:

Given

angular speed of first shaft $\omega _1=420\ rev/min$

Moment of inertia of second shaft is seven times times the rotational speed of the first i.e. If I is the moment of inertia of first wheel so moment of inertia of second is 7 I

As there is no external torque therefore angular momentum is conserved

$L_1=L_2$

$I_1\omega _1=I_2\omega _2$

$I\times (420)=7 I\times (\omega _2)$

$\omega _2=\frac{420}{7}$

$\omega _2=60\ rev/min$

8 0

3 years ago

1 give reason

Anastaziya [24]

Answer:

A. The melting of ice is both a desirable and undesirable change because, ice is needed to melt so as to make liquid water available for animal and plant use and consumption and also to release the energy used in the fusion process of ice formation. Melting of ice is undesirable because melting ice liberate water slowly, and the water liberated can erode surface soil. Melting ice reduces the available heat sink on earth and also reduces the available stored up fresh water supply on earth.

B. The appearance of hailey comet once every 72 year is a periodic change because it's motion around the solar system is repeated with time. The reason for this highly elliptical and eccentric path of motion is largely due to the gravitational effect of the sun and the planets on the comet.

4 0

3 years ago

A Bugatti Chiron travels 116 m/s for 10 seconds. How far did it travel? A. 116 m B. 11.6m C. 0.086m D. 1.160m

Sunny_sXe [5.5K]

Answer:

V= 1,160 m

Explanation:

formula:

V= V* T

remplazamos:

V= 116m /s * 10s

V= 1,160 m

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3 0

2 years ago