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frez [133]
2 years ago
14

Water is being heated in a closed pan on top of a range while being stirred by a paddle wheel. During the process, 30 kJ of heat

is transferred to the water, and 5 kJ of heat is lost to the surrounding air. The paddle-wheel work amounts to 500 N ∙ m. Determine the final energy of the system if its initial energy is 10 kJ. [
Physics
1 answer:
schepotkina [342]2 years ago
3 0

Answer:

35.5KJ

Explanation:

Heat transferred (Q) = change in internal energy (∆U) + work done (W)

Q = 30KJ, W = 500Nm = 500J = 500/1000KJ = 0.5KJ

∆U = Q - W = 30 - 0.5 = 25.5KJ

∆U = final energy (U2) - initial energy (U1)

U2 = ∆U + U1 = 25.5 + 10 = 35.5KJ

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Answer:

  0.00325 moles/liter/second

Explanation:

The tangent line has a slope of (y2 -y1)/(x2 -x1) = (0.35-0.48)/(40-0) = -0.00325.

The rate of the reaction is about 0.00325 moles/liter/second.

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5 0
2 years ago
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A river flows with a uniform velocity vr. A person in a motorboat travels 1.22 km upstream, at which time she passes a log float
storchak [24]

Answer:

 t ’= \frac{1450}{0.6499 + 2 v_r},  v_r = 1 m/s       t ’= 547.19 s

Explanation:

This is a relative velocity exercise in a dimesion, since the river and the boat are going in the same direction.

By the time the boat goes up the river

        v_b - v_r = d / t

By the time the boat goes down the river

        v_b + v_r = d '/ t'

let's subtract the equations

       2 v_r = d ’/ t’ - d / t

       d ’/ t’ = 2v_r + d / t

       t' = \frac{d'}{ \frac{d}{t}+ 2 v_r }

In the exercise they tell us

         d = 1.22 +1.45 = 2.67 km= 2.67 10³ m

         d ’= 1.45 km= 1.45 1.³ m

at time t = 69.1 min (60 s / 1min) = 4146 s

the speed of river is v_r

      t ’= \frac{1.45 \ 10^3}{ \frac{ 2670}{4146} \  + 2 \ v_r}

      t ’= \frac{1450}{0.6499 + 2 v_r}

In order to complete the calculation, we must assume a river speed

          v_r = 1 m / s

       

let's calculate

      t ’= \frac{ 1450}{ 0.6499 + 2 \ 1}

      t ’= 547.19 s

8 0
2 years ago
Which of these shows unbalanced forces at work on an object? A. an ice skater turning as he skates around an ice rink B. a bicyc
rosijanka [135]
I’m pretty sure the answer is a
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2 years ago
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a small bar magnet is suspended horizontally by a string. When placed in a uniform horizontal magnetic field, it will
Reil [10]

Answer:

It will neither translate in the opposite direction nor .rotate so as to be at right angles, it will also neither rotate so as to be vertical direction

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The 8 kg block is then released and accelerates to the right, toward the 2 kg block. The surface is rough and the coefficient of
natita [175]

Answer:

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x = Displacement of spring = 0.7 m (Assumed, as it is not given)

\mu = Coefficient of friction = 0.4

Energy stored in spring is given by

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The speed of the 8 kg block just before collision is 3.258 m/s

7 0
2 years ago
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