A computer monitor has a power rating of 0.240 kw?

a. A rectangular pen is built with one side against a barn. 1900 m of fencing are used for the other three sides of the pen. Wha

Natalka [10]

Answer:

475 m , 950 m

Explanation:

Let l be the length of the side perpendicular to the barn.

1900-2l = length of the side parallel to the barn

Area A= l( 1900-2l)

A= 1900l-2l^2

now, the maximum value of l ( the equation being quadratic)

l_max= -b/2a

a= 2

b=1900

l_max= -1900/4= 475 m

then 1900-2l= 1900-2×(475) = 950 m

So, the dimensions that maximize area are

950 and 475

Now. A_max = -2( l_max)^2+1900×l_max

A_max= -2(475)^2+1900×475

A_max= 451250 m^2

or, 475×950 = 451250 m^2

6 0

4 years ago

How much work was done to accelerate a 2.2 kg object from rest to 26m/s?

Makovka662 [10]

Answer:

Explanation:

work done = change in kinetic energy, assuming there are no energy losses.

work done = 1/2 × m × change in v^2

= 1/2 × 2.2 × ( 26^2 - 0^2)

= 1/2 × 2.2 × 676

= 743.6 joules

4 0

2 years ago

A girl swings on a playground swing in such a way that at her highest point she is 4.1 m from the ground, while at her lowest po

Umnica [9.8K]

Answer:

V1 =8.1 m/s

Explanation:

height at highest point (h2) = 4.1 m

height at lowest point (h1) = 0.8 m

acceleration due to gravity (g) = 9.8 m/s^{2}

from conservation of energy, the total energy at the lowest point will be the same as the total energy at the highest point. therefore

mgh1 + $0.5mV1^{2}$ = mgh2 + $0.5mV2^{2}$

where

speed at highest point = V2

speed at lowest point = V1

mass of the girl and swing = m

at the highest point, the speed is minimum (V1 = 0)

at the lowest point the speed is maximum (V2 is the maximum speed)

therefore the equation becomes mgh1 + $0.5mV1^{2}$ = mgh2

m(gh1 + $0.5V1^{2}$ ) = m(gh2)

gh1 + $0.5V1^{2}$ = gh2

V1 = $\sqrt{\frac{gh2 - gh1}{0.5}}$

now we can substitute all required values into the equation above.

V1 = $\sqrt{\frac{(9.8x4.1) - (9.8x0.8)}{0.5}}$

V1 = $\sqrt{\frac{32.34}{0.5}}$

V1 =8.1 m/s

8 0

4 years ago

As a bicycle pump inflates a tyre, it pressure rises from 30 kPa to 40 kPa at constant temperature of 30 °C. By assuming the air

MArishka [77]

This question involves the concepts of work done, pressure, and temperature.

The work done per mol of the air is "-724.71 J/mol".

Using the given formula for work done:

$W=RTln\frac{P_1}{P_2}$

where,

W = work done per mol = ?

R = universal gas constant = 8.314 J/mol.k

T = absolute temperature = 30°C + 273 = 303 k

P₁ = initial pressure = 30 KPa

P₂ = final pressure = 40 KPa

Therefore,

$W= (8.314\ J/mol.k)(303\ k)ln\frac{30\ KPa}{40\ KPa}\\$

W = -724.71 J/mol

Learn more about pressure here:

brainly.com/question/23358029?referrer=searchResults

7 0

3 years ago

n this experiment, you will measure mass and volume of various sport balls, both regularly shaped ball and irregularly shaped. W

pentagon [3]

Explanation :

Density of an object can determine using mass and volume. We can measure mass and volume of various sports ball, both regular shaped ball and irregular shaped ball.

Density for regularly shaped ball and that of irregularly shaped ball is different.

Suppose that mass of an object is 100g and the volume is $2000\ cm^3$ . So, using this data we can find density of that object as

$density=\frac{mass}{volume}$

$\rho =\frac{100}{2000}$

$\rho =0.05\ g/cm^3$

5 0

3 years ago

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A computer monitor has a power rating of 0.240 kw?​

A computer monitor has a power rating of 0.240 kw?