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2 years ago

An adiabatic closed system is accelerated from 0 m/s to 30 m/s. Determine the specific energy change of this system, in kJ/kg.

Physics

1 answer:

snow_tiger [21]2 years ago

6 0

Answer:

Explanation:

initial velocity, u = 0 m/s

final velocity, v = 30 m/s

Let the mass is m .

Initial kinetic energy, Ki = 1/2 mu² = 0

Final kinetic energy, Kf = 1/2 mv² = 0.5 m x 30 x 30 = 450 m

Specific energy change = change in kinetic energy per unit mass

= 450 m / m = 450 J/kg = 0.45 kJ/kg

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A baseball of mass m = 0.49 kg is dropped from a height h1 = 2.25 m. It bounces from the concrete below and returns to a final h

Brilliant_brown [7]

Answer:

Explanation:

Impulse = change in momentum

mv - mu , v and u are final and initial velocity during impact at surface

For downward motion of baseball

v² = u² + 2gh₁

= 2 x 9.8 x 2.25

v = 6.64 m / s

It becomes initial velocity during impact .

For body going upwards

v² = u² - 2gh₂

u² = 2 x 9.8 x 1.38

u = 5.2 m / s

This becomes final velocity after impact

change in momentum

m ( final velocity - initial velocity )

.49 ( 5.2 - 6.64 )

= .7056 N.s.

Impulse by floor in upward direction

= .7056 N.s

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1 year ago

Two loudspeakers 42.0 m apart and facing each other emit identical 115 Hz sinusoidal sound waves in a room where the sound speed

Tems11 [23]

Answer:

She passes through a loud spot at x = 19.5m from the first speaker. Constructive interference occurs here.

At the quiet spot destructive interference occurs. The minimum distance for this to occur is 20.25 from the first speaker.

Explanation:

3 0

1 year ago

A truck pulled a car of 2,350 kg a distance of 25 meters. If the car accelerates from 3 m/s to 6 m/s, whats the average force ex

faust18 [17]

Answer:

1,269 N

Explanation:

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1 year ago

An electron in a vacuum chamber is fired with a speed of 9800 km/s toward a large, uniformly charged plate 75 cm away. The elect

melisa1 [442]

Answer:

The plate's surface charge density is $-8.056\times10^{-9}\ C/m^2$

Explanation:

Given that,

Speed = 9800 km/s

Distance d= 75 cm

Distance d' =15 cm

Suppose we determine the plate's surface charge density?

We need to calculate the surface charge density

Using work energy theorem

$W=\Delta K.E$

$W=\dfrac{1}{2}mv_{f}^2-\dfrac{1}{2}mv_{i}^2$

Here, final velocity is zero

$W=0-\dfrac{1}{2}mv_{i}^2$ ...(I)

We know that,

$W=-Fd$

$W=-E\times e\times d$

$W=-\dfrac{\lambda}{2\epsilon_{0}}\times e\times d$ ...(II)

From equation (I) and (II)

$-\dfrac{1}{2}mv_{i}^2=-\dfrac{\lambda}{2\epsilon_{0}}\times e\times d$

Charge is negative for electron

$\lambda=\dfrac{mv^2\epsilon_{0}}{(-e)d}$

Put the value into the formula

$\lambda=-\dfrac{9.1\times10^{-31}\times(9800\times10^{3})^2\times8.85\times10^{-12}}{1.6\times10^{-19}\times(75-15)\times10^{-2}}$

$\lambda=-8.056\times10^{-9}\ C/m^2$

Hence, The plate's surface charge density is $-8.056\times10^{-9}\ C/m^2$

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2 years ago

The power ratings of several motors are listed in the table.

storchak [24]

<span>The power ratings of several motors are listed in the table.
Motor Power
Brandy X 7,460
Brandy Y 7,650
Brandy Z 7,580

An advertising agency writes marketing material for a new motor (Brand W) that has a power rating of 7,640 W. Which statement comparing the motors can they truthfully use?

I believe the answer is </span><span>Brand W motor does more work each second than Brand X or Brand Z.</span>

4 0

2 years ago

Read 2 more answers