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Assoli18 [71]
2 years ago
6

Suppose an electrical wire is replaced with one having every linear dimension doubled (i.e., the length and radius have twice th

eir original values). How is the resistance of the wire affected?
Physics
1 answer:
Flauer [41]2 years ago
4 0

Answer:

The new resistance becomes half of the initial resistance.

Explanation:

The resistance of a wire is given by :

R=\dfrac{\rho L}{A}

\rho = resistivity of material

L and A are linear dimension

If the electrical wire is replaced with one having every linear dimension doubled i.e. l' = 2l and r' = 2r

New resistance of wire is given by :

R'=\dfrac{\rho L'}{A'}

R'=\dfrac{\rho (2L)}{\pi (2r)^2}

R'=\dfrac{1}{2}\dfrac{\rho L}{A}

R'=\dfrac{1}{2}R

The new resistance becomes half of the initial resistance. Hence, this is the required solution.

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A climatograph for a tropical grassland or savanna would look different from the climatograph shown for a temperate grassland. D
Savatey [412]

Answer:

Savannas have a fairly constant temperature all year; temperate grasslands have a greater seasonal temperature variation.

Explanation:

For example, the African Savanna has an almost constant temperature all year (see the first figure below).

The difference between summer and winter temperatures is only about 5 °C, and the rate of temperature change is quite slow.

The temperature of a temperate grassland (see the second figure below) has a much greater seasonal variation.  

The summers are hot, and the winters are cold. The difference between summer and winter temperatures is about 30 °C, with a rapid rate of temperature change from one season to the next.

5 0
2 years ago
In a jump spike, a volleyball player slams the ball from overhead and toward the opposite floor. controlling the angle of the sp
8090 [49]
V ( initial ) = 20 m/s
h = 2.30 m
h = v y * t + g t ² / 2
d = v x * t
1 ) At α = 18°:
v y = 20 * sin 18° = 6.18 m/s
v x = 20 * cos 18° = 19.02 m/ s
2.30 = 6.18 t + 4.9 t²
4.9 t² + 6.18 t - 2.30 = 0
After solving the quadratic equation ( a = 4.9, b = 6.18, c = - 2.3 ):
t 1/2 = (- 6.18 +/- √( 6.18² - 4 * 4.9 * (-2.3)) ) / ( 2 * 4.9 )  
t = 0.3 s
d 1 = 19.02 m/s * 0.3 s = 5.706 m
2 ) At  α = 8°:
v y = 20* sin 8° = 2.78 m/s
v x = 20* cos 8° = 19.81 m/s
2.3 = 2.78 t + 4.9 t² 
4.9 t² + 2.78 t - 2.3 = 0
t = 0.46 s
d 2 = 19.81 * 0.46 = 9.113 m
The distance is:
d 2 - d 1 = 9.113 m - 5.706 m = 3.407 m

GOOD LUCK AND HOPE IT HELPS U
6 0
2 years ago
An ideal monatomic gas initially has a temperature of T and a pressure of p. It is to expand from volume V1 to volume V2. If the
yawa3891 [41]

Answer:

Isothermal :   P2 = ( P1V1 / V2 ) ,  work-done pdv = nRT * In( \frac{V2}{v1} )

Adiabatic : : P2 = \frac{P1V1^{\frac{5}{3} } }{V2^{\frac{5}{3} } }  , work-done =

W = (3/2)nR(T1V1^(2/3)/(V2^(2/3)) - T1)

Explanation:

initial temperature : T

Pressure : P

initial volume : V1

Final volume : V2

A) If expansion was isothermal calculate final pressure and work-done

we use the gas laws

= PIVI = P2V2

Hence : P2 = ( P1V1 / V2 )

work-done :

pdv = nRT * In( \frac{V2}{v1} )

B) If the expansion was Adiabatic show the Final pressure and work-done

final pressure

P1V1^y = P2V2^y

where y = 5/3

hence : P2 = \frac{P1V1^{\frac{5}{3} } }{V2^{\frac{5}{3} } }

Work-done

W = (3/2)nR(T1V1^(2/3)/(V2^(2/3)) - T1)

Where    T2 = T1V1^(2/3)/V2^(2/3)

3 0
2 years ago
A car is pulled with a force of 10,000 N. The car's mass is 1267 kg. But, the car covers 394.6 m in 15 seconds
solong [7]

A. Formula: F=ma or F/m=a

10,000N/1,267kg≈7.9m/s^{2}

B. Formula: a=\frac{V-V_{0} }{t} and s=d/t

speed= 394.6/15

s=26.3m/s

a=\frac{26.3-0}{15}

a=1.75m/s^{2}

C. 7.9-1.75=difference of 6.15m/s^{2}

D. The force that most likely caused this difference is friction forces

3 0
2 years ago
Read 2 more answers
A highway curve with radius R = 274 m is to be banked so that a car traveling v = 25.0 m/s will not skid sideways even in the ab
belka [17]

Answer:

A)   θ = 13.1º  , B)  E

Explanation:

A) For this exercise, let's use Newton's second law, let's set a reference frame where the axis ax is in the radial direction and is horizontal, the axis y is vertical.

In this reference system the only force that we must decompose is the Normal one, let's use trigonometry

        sin θ = Nₓ / N

        cos θ = N_{y} / N

        Nₓ = N sin θ

       Ny = N cos θ

x-axis (radial)

        Nₓ = m a

where the acceleration is centripetal

         a = v² / R

we substitute

        -N sin θ = -m v² / R                   (1)

the negative sign indicates that the force and acceleration towards the center of the circle

y-axis (Vertical)

          Ny - W = 0

           N cos θ = mg

           N = mg / cos θ

we substitute in 1

          mg / cos θ  sin θ = m v² / R

          g tan θ = v² / R

          θ = tan⁻¹ (v² / gR)

we calculate

        θ = tan⁻¹ (25² / 9.8 274)

        θ = 13.1º

B) when comparing the equations the correct one is E

6 0
2 years ago
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