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3 years ago

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One of the most efficient heat engines ever built is a coal-fired steam turbine in the Ohio River valley, operating between 1 87

0°C and 430°C.
(a) What is its maximum theoretical efficiency? %

(b) The actual efficiency of the engine is 42.0%. How much mechanical power does the engine deliver if it absorbs 1.30 105 J of energy each second from its hot reservoir?

1 answer:

k0ka [10]3 years ago

5 0

Answer:The answer

Explanation:

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A diver is on a board 1.80 m above

Virty [35]

Answer:

v = 6.95 m/s

Explanation:

Given that,

A diver is on a board 1.80 m above the water, s = 1.8 m

The initial speed of the diver, u = 3.62 m/s

Let v is the speed with which she hit the water. It will move under the action of gravity. Using the equation of motion as follows :

$v^2-u^2=2gs\\\\v=\sqrt{u^2+2gs} \\\\v=\sqrt{(3.62)^2+2(9.8)(1.8)} \\\\v=6.95\ m/s$

So, she will hit the water with a speed of 6.95 m/s.

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3 years ago

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A block of ice at 0 degrees C, whose mass is initially 62 kg, slides along a horizontal surface, starting at a speed of 5.48 m/s

Kryger [21]

The mass of ice melted as a result of friction between the ice and the horizontal surface is 2.78g

<u>Explanation:</u>

Given,

Temperature, T = 0°C

Initial mass, Mi = 62kg

Speed, s = 5.48m/s

Distance, x = 26.8m

Friction is present.

Mass of ice melted = ?

We know,

The amount of energy required for the melting of ice is exactly equal to the initial kinetic energy of the block of ice

and

$Kinetic Energy, KE = \frac{1}{2} mv^2$

Therefore, $KE = \frac{62 X 5.48 X 5.48}{2}$

KE = 930.94 Joules

Ice melting lateral heat is 334 kJ/kg = 334000 J/kg.

Therefore, the melted mass of the ice = 930.94 / 334000 = 0.00278 kg = 2.78 g.

Thus, The mass of ice melted as a result of friction between the ice and the horizontal surface is 2.78g

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3 years ago

What kind of energy does a baseball use when travels thru the air?

notka56 [123]

Kinetic energy is what a baseball use while traveling in the air

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3 years ago

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True or false: Decreased output from the vasomotor center allows arterioles and veins to constrict.

wolverine [178]

<h3><u>Answer;</u></h3>

The above statement is False

<h3><u>Explanation;</u></h3>

Decreased output from the vasomotor center allows arterioles and veins to dilate.
The vasomotor center controls vessel tone or contraction of the smooth muscle in the tunica media.It is responsible for central regulation of cardiac electrical activity, myocardial performance, and peripheral vascular tone.
Changes in diameter affect peripheral resistance, pressure, and flow, which in turn affect cardiac output.

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2 years ago

A solid sphere is released from the top of a ramp that is at a height h1 = 2.30 m. It rolls down the ramp without slipping. The

Oksi-84 [34.3K]

Answer:

The horizontal distance d does the ball travel before landing is 1.72 m.

Explanation:

Given that,

Height of ramp $h_{1}=2.30\ m$

Height of bottom of ramp $h_{2}=1.69\ m$

Diameter = 0.17 m

Suppose we need to calculate the horizontal distance d does the ball travel before landing?

We need to calculate the time

Using equation of motion

$h_{2}=ut+\dfrac{1}{2}gt^2$

$t=\sqrt{\dfrac{2h_{2}}{g}}$

$t=\sqrt{\dfrac{2\times1.69}{9.8}}$

$t=0.587\ sec$

We need to calculate the velocity of the ball

Using formula of kinetic energy

$K.E=\dfrac{1}{2}mv^2+\dfrac{1}{2}I\omega^2$

$K.E=\dfrac{1}{2}mv^2+\dfrac{1}{2}\times(\dfrac{2}{5}mr^2)\times(\dfrac{v}{r})^2$

$K.E=\dfrac{7}{10}mv^2$

Using conservation of energy

$K.E=mg(h_{1}-h_{2})$

$\dfrac{7}{10}mv^2=mg(h_{1}-h_{2})$

$v^2=\dfrac{10}{7}\times g(h_{1}-h_{2})$

Put the value into the formula

$v=\sqrt{\dfrac{10\times9.8\times(2.30-1.69)}{7}}$

$v=2.922\ m/s$

We need to calculate the horizontal distance d does the ball travel before landing

Using formula of distance

$d =vt$

Where. d = distance

t = time

v = velocity

Put the value into the formula

$d=2.922\times 0.587$

$d=1.72\ m$

Hence, The horizontal distance d does the ball travel before landing is 1.72 m.

8 0

3 years ago