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vagabundo [1.1K]

3 years ago

3

High-voltage power lines are a familiar sight throughout the country. The aluminum wire used for some of these lines has a cross

-sectional area of 5.00 10-4 m2. What is the resistance of ten kilometers of this wire?

1 answer:

ale4655 [162]3 years ago

6 0

Answer:

Resistance, R = 0.564 ohms

Explanation:

Area of cross section of the aluminium wire, $A=5\times 10^{-4}\ m^2$

Length of the wire, L = 10 km

Resistivity of the aluminium wire is, $\rho=2.82\times 10^{-8}\ \Omega-m$

The resistivity of a wire is given by the relation as follows :

$R=\rho\dfrac{L}{A}\\\\R=2.82\times 10^{-8}\times \dfrac{10\times 10^3}{5\times 10^{-4}}\\\\R=0.564\ \Omega$

So, the resistance of the wire is 0.564 ohms.

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In a game of pool, a cue ball rolls without slipping toward the stationary eight ball with a momentum of 0.23 kg. After the two

IrinaVladis [17]

This question involves the concepts of the law of conservation of momentum.

The magnitude of the final momentum of the eight ball is "0.22 N.s".

According to the law of conservation of momentum:

$P_{i1}+P_{i2}=P_{f1}+P_{f2}$

where,

$P_{i1}$ = initial momentum of the cue ball = 0.23 N.s

$P_{i2}$ = initial momentum of the eight ball = 0 N.s (since ball is initially at rest)

$P_{f1}$ = final momentum of the cue ball = 0.01 N.s

$P_{f2}$ = final momentum of the eight ball = ?

Therefore,

$0.23\ N.s + 0\N.s = 0.01\ N.s+P_{f2}\\\\P_{f2} = 0.22\ N.s$

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3 years ago

A constant electric field with magnitude 1.50 ✕ 103 N/C is pointing in the positive x-direction. An electron is fired from x = −

romanna [79]

Answer:

The speed of electron is $1.5\times10^{7}\ m/s$

Explanation:

Given that,

Electric field $E=1.50\times10^{3}\ N/C$

Distance = -0.0200

The electron's speed has fallen by half when it reaches x = 0.190 m.

Potential energy $P.E=5.04\times10^{-17}\ J$

Change in potential energy $\Delta P.E=-9.60\times10^{-17}\ J$ as it goes x = 0.190 m to x = -0.210 m

We need to calculate the work done by the electric field

Using formula of work done

$W=-eE\Delta x$

Put the value into the formula

$W=-1.6\times10^{-19}\times1.50\times10^{3}\times(0.190-(-0.0200))$

$W=-5.04\times10^{-17}\ J$

We need to calculate the initial velocity

Using change in kinetic energy,

$\Delta K.E = \dfrac{1}{2}m(\dfrac{v}{2})^2+\dfrac{1}{2}mv^2$

$\Delta K.E=\dfrac{-3mv^2}{8}$

Now, using work energy theorem

$\Delta K.E=W$

$\Delta K.E=\Delta U$

So, $\Delta U=W$

Put the value in the equation

$\dfrac{-3mv^2}{8}=-5.04\times10^{-17}$

$v^2=\dfrac{8\times(5.04\times10^{-17})}{3m}$

Put the value of m

$v=\sqrt{\dfrac{8\times(5.04\times10^{-17})}{3\times9.1\times10^{-31}}}$

$v=1.21\times10^{7}\ m/s$

We need to calculate the change in potential energy

Using given potential energy

$\Delta U=-9.60\times10^{-17}-(-5.04\times10^{-17})$

$\Delta U=-4.56\times10^{-17}\ J$

We need to calculate the speed of electron

Using change in energy

$\Delta U=-W=-\Delta K.E$

$\Delta K.E=\Delta U$

$\dfrac{1}{2}m(v_{f}^2-v_{i}^2)=4.56\times10^{-17}$

Put the value into the formula

$v_{f}=\sqrt{\dfrac{2\times4.56\times10^{-17}}{9.1\times10^{-31}}+(1.21\times10^{7})^2}$

$v_{f}=1.5\times10^{7}\ m/s$

Hence, The speed of electron is $1.5\times10^{7}\ m/s$

4 0

3 years ago

consider a charged parallel-plate capacitor. which combination of changes would quadruple its capacitance?

kogti [31]

Its capacitance Double the charge and double the plate area.

Doubling the distance between the plates of a capacitor double the capacitance. Doubling the distance between the plates of a capacitor quadruples the capacitance. As the distance between the plates decreases, the capacitance increases because the potential difference decreases.

Halving the distance between the plates of a parallel plate capacitor doubles the capacitance of the capacitor from its initial capacitance. When two or more capacitors are connected in parallel, the overall effect is that of a single equivalent capacitor with the sum of the plate areas of the individual capacitors. As we saw earlier all other factors being equal, more disk space equals more capacity.

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What is the first step a scientist usually take to solve a problem?

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Make prediction about what will happen certain circumstances

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4 years ago

Please help me do this. Study the scenario.

dem82 [27]

The mechanical advantage of the lever is 3 and the right option is A.) 3.

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Mechanical advantage can be defined as the ratio of load to effort in a machine.

To calculate the mechanical advantage of the lever, we use the formula below.

Formula

M.A = y/x................ Equation 1

Where:

M.A = mechanical advantage of the lever
y = distance moved by effort (input arm)
x = distance moved by load (output arm)

From the question,

Given:

y = 3 m
x = 1 m

Substitute these values into equation 1

M.A = 3/1
M.A = 3.

Hence, The mechanical advantage of the lever is 3 and the right option is A.) 3.

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8 0

3 years ago