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3 years ago

20 points come an get it ppl! :D

1 answer:

5 0

<span>In the sentence "Pretend you are an electron in a copper wire which is being used to connect a battery to a flashlight bulb. Because this circuit uses a (n) ___________________ current, you as the electron in the wire will" the phrase the completes the sentence is C, alternating, move only in one direction.</span>

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A 1.50x103-kilogram car is traveling east at 30 meters per second.

frez [133]

Answer:

$39000\ \text{kg m/s}$

West

Explanation:

m = Mass of car = $1.3\times 10^{3}\ \text{kg}$

t = Time = 9 seconds

u = Initial velocity = 30 m/s

v = Final velocity = 0

Impulse is given by

$J=m(v-u)\\\Rightarrow J=1.3\times 10^3(0-30)\\\Rightarrow J=-39000\ \text{kg m/s}$

The magnitude of the total impulse applied to the car to bring it to rest is $39000\ \text{kg m/s}$ .

The direction is towards west as the sign is negative.

7 0

3 years ago

Too much skepticism can

Artyom0805 [142]

What part of the bacterial cell helps it stick to surfaces

3 0

3 years ago

A rigid, insulated tank whose volume is 10 L is initially evacuated. A pinhole leak develops and air from the surroundings at 1

balandron [24]

Answer:

The answer is " $143.74^{\circ} \ C , 8.36\ g, and \ 2.77\ \frac{K}{J}$ "

Explanation:

For point a:

Energy balance equation:

$\frac{dU}{dt}= Q-Wm_ih_i-m_eh_e\\\\$

$W=0\\\\Q=0\\\\m_e=0$

From the above equation:

$\frac{dU}{dt}=0-0+m_ih_i-0\\\\\Delta U=\int^{2}_{1}m_ih_idt\\\\$

because the rate of air entering the tank that is $h_i$ constant.

$\Delta U = h_i \int^{2}_{1} m_i dt \\\\= h_i(m_2 -m_1)\\\\m_2u_2-m_1u_2=h_i(M_2-m_1)\\\\$

Since the tank was initially empty and the inlet is constant hence, $m_2u-0=h_1(m_2-0)\\\\m_2u_2=h_1m_2\\\\u_2=h_1\\\\$

Interpolate the enthalpy between $T = 300 \ K \ and\ T=295\ K$ . The surrounding air

temperature:

$T_1= 25^{\circ}\ C\ (298.15 \ K)\\\\\frac{h_{300 \ K}-h_{295\ K}}{300-295}= \frac{h_{300 \ K}-h_{1}}{300-295.15}$

Substituting the value from ideal gas:

$\frac{300.19-295.17}{300-295}=\frac{300.19-h_{i}}{300-298.15}\\\\h_i= 298.332 \ \frac{kJ}{kg}\\\\Now,\\\\h_i=u_2\\\\u_2=h_i=298.33\ \frac{kJ}{kg}$

Follow the ideal gas table.

The $u_2= 298.33\ \frac{kJ}{kg}$ and between temperature $T =410 \ K \ and\ T=240\ K.$

Interpolate

$\frac{420-410}{u_{240\ k} -u_{410\ k}}=\frac{420-T_2}{u_{420 k}-u_2}$

Substitute values from the table.

$\frac{420-410}{300.69-293.43}=\frac{420-T_2}{{u_{420 k}-u_2}}\\\\T_2=416.74\ K\\\\=143.74^{\circ} \ C\\\\$

For point b:

Consider the ideal gas equation. therefore, p is pressure, V is the volume, m is mass of gas. $\bar{R} \ is\ \frac{R}{M}$ (M is the molar mass of the gas that is $28.97 \ \frac{kg}{mol}$ and R is gas constant), and T is the temperature.

$n=\frac{pV}{TR}\\\\$

$=\frac{(1.01 \times 10^5 \ Pa) \times (10\ L) (\frac{10^{-3} \ m^3}{1\ L})}{(416.74 K) (\frac{8.314 \frac{J}{mol.k} }{2897\ \frac{kg}{mol})}}\\\\=8.36\ g\\\\$

For point c:

Entropy is given by the following formula:

$\Delta S = mC_v \In \frac{T_2}{T_1}\\\\=0.00836 \ kg \times 1.005 \times 10^{3} \In (\frac{416.74\ K}{298.15\ K})\\\\=2.77 \ \frac{J}{K}$

5 0

3 years ago

A driver's foot presses with a steady force of 20N on a pedal in a car as shown.

azamat

Answer:

160N

Explanation:

Moments must be conserved - so.

$20 * 0.4 = F * 0.05$

$F=\frac{20*0.4}{0.05} = 160$

6 0

4 years ago

The equivalence between gravitational and inertial mass is explained in : the set of all of the events that happened on Earth

xxTIMURxx [149]

Answer:

The correct answer is theory of general relativity.

Explanation:

According to the statement of equivalence the gravitational mass force on an object standing on the surface of earth is same as the pseudo force that acts on it if it accelerated at acceleration equal to acceleration due to gravity.

According to Einestine both the forces are indistinguishable as both the forces produce same effects. Thus both are equivalent and thus gravity is a phenomenon that can be analysed in a radically different way which gives some strange results such as bending of light, existence of black holes,e.t.c

6 0

3 years ago