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4 years ago

A conducting wire is quadrupled in length and tripled in diameter.

Physics

2 answers:

aivan3 [116]4 years ago

7 0

Answer:

Its resistance decreases

Explanation:

The resistance of a wire is directly proportional to the length of the wire and inversely proportional to the cross sectional area of the wire.

Mathematically,

R1 =¶L1/A1... (1)

R1= ¶L1/{Πd²/4}

R1= 4¶L1/Πd²

where;

¶ is the constant of proportionality which is the resistivity of the material

L is the length of the wire

A is the cross sectional area

A1 = Πd²/4

If the length is quadrupled and its diameter tripled

The new length L2 will be 4L1

New area A2 = Π(3d)²/4 = 9Πd²/4

The resistance will become

R2 = ¶(4L1)/{9Πd²/4}

R2 = 4¶L1×4/9Πd²

R2 = 16¶L1/9Πd²... (2)

R2/R1 = 16¶L1/9Πd²÷4¶L1/Πd²

R2/R1 = 16¶L1/9Πd²×Πd²/4¶L1

R2/R1 = 16/9×1/4

R2/R1 = 16/36

R2/R1 = 4/9

R2 = 4/9R1

This shows that the resistance of the wire decreases

Karo-lina-s [1.5K]4 years ago

4 0

Explanation:

Below is an attachment containing the solution.

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3 years ago

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1:-

$\\ \sf\longmapsto cos\Theta=\dfrac{B}{H}$

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3 years ago

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A hot air balloon of total mass M (including passengers and luggage) is moving with a downward acceleration of magnitude a. As i

frez [133]

Answer:

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when some of the mass m is dropped and balloon is moving in upward direction with acceleration a/2 then,

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Adding equation (i) and (ii)

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3 years ago

What happens to a light ray if it is incident on a reflective surface along the normal?

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Answer: The incident ray and the reflected ray and the normal will be parallel to each other.

Explanation:

The normal is perpendicular to the surface of the mirror or the reflective surface.

According to the law of reflection which state that:

The angle of incidence is always equal to the angle of reflection on a smooth surface.

If a light ray is incident on a reflective surface along the normal. The angle of incidence will be at 90 degrees which will be perpendicular to the surface of the mirror, the reflected ray will bounce back likewise at the same angle which will be perpendicular to the reflective surface.

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3 years ago

A freight car with a mass of 10 metric tons is rolling at 108 km/h along a level track when it collides with another freight car

Rufina [12.5K]

Answer:

20 metric tons

Explanation:

Using the Principle of Conservation of Linear Momentum which states that the total momentum of a system is constant in any direction in which no external force acts.

momentum before collision= momentum after collision

mathematically expressed as

m1u1 + m2u2 = m1v1+m2v2 =0

where:

m1= mass of rolling freight car = 10 metric tons = 10Mg

1 ton = 1000kg= 1Mg

u1 =initial velocity of freight car = 108km/h,

m2 = mass of stationary freight car = ?, this the unknown we are finding

u2 = initial velocity of

m2 = 0, because it is at rest,

v1= final velocity of m1,

v2= final velocity of m2

since they move together in the same direction they share a common final velocity as such

v1=v2= 36km/h

substituting valves in expression give

m1u1 + m2u2 = m1v1 + m2v2= 0

10Mgx 108km/hr + m2 x 0 = 10Mg x 36km/h + m2x36km/h

1080( Mg x km/hr) + 0 = 360 (Mg x Km/h) + 36m2 (km/h)

1080 (Mgx km/hr) - 360(Mg x km/h) = 36m2 (km/h)

720(Mg x km/h) = 36m2 (km/h)

divide both side by 36 (km/h) gives

m2 = 20Mg =20 metric tons

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