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3 years ago

12. The resistivity of a given wire of cross-sectional

Physics

1 answer:

luda_lava [24]3 years ago

3 0

R = resistivity × (l/A), A = πr^2= πd^2/4

2 =( 4.9 × 10^ -4) * (l/π0.7^2/4)

make l the subject and calculate.

i assumed we are looking for the length if the wire.

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If the earth shrank until its radius were only one-quarter its present size without changing its mass what would a 20 n object w

Dahasolnce [82]

Basing on the information given, we can calculate the new weight of the object by the following given:current weight = 20 Ng = 10m/s2

20N/4 = 5N

Thank you for your question. Please don't hesitate to ask in Brainly your queries.

5 0

3 years ago

The Hubble Space Telescope orbits the Earth at approximately 612,000m altitude. Its mass is 11,100 kg and the mass of earth is 5

nexus9112 [7]

Answer:

7.55 km/s

Explanation:

The force of gravity between the Earth and the Hubble Telescope corresponds to the centripetal force that keeps the telescope in uniform circular motion around the Earth:

$G\frac{mM}{R^2}=m\frac{v^2}{R}$

where

$G=6.67\cdot 10^{-11} m^3 kg^{-1} s^{-2}$ is the gravitational constant

$m=11,100 kg$ is the mass of the telescope

$M=5.97\cdot 10^{24} kg$ is the mass of the Earth

$R=r+h=6.38\cdot 10^6 m+612,000 m=6.99\cdot 10^6 m$ is the distance between the telescope and the Earth's centre (given by the sum of the Earth's radius, r, and the telescope altitude, h)

v = ? is the orbital velocity of the Hubble telescope

Re-arranging the equation and substituting numbers, we find the orbital velocity:

$v=\sqrt{\frac{GM}{R}}=\sqrt{\frac{(6.67\cdot 10^{-11})(5.97\cdot 10^{24} kg)}{6.99\cdot 10^6 m}}=7548 m/s=7.55 km/s$

6 0

3 years ago

What makes a funnel appear black

fredd [130]

Answer:

Air

Explanation:

The mixing of cooler air in the lower troposphere with air flowing in a different direction in the middle troposphere causes the rotation on a horizontal axis, which, when deflected and tightened vertically by convective updrafts, forms a vertical rotation that can cause condensation to form a funnel cloud.

6 0

3 years ago

Define wheel and axle in science terms

topjm [15]

Answer:

A simple machine consisting of an axle to which a wheel is fastened so that torque applied to the wheel winds a rope or chain onto the axle, yielding a mechanical advantage equal to the ratio of the diameter of the wheel to that of the axle.

5 0

3 years ago

The musical tone a piano has a frequency of 346HZ and a wavelength of 1.3 M what is the speed of the sound

prohojiy [21]

Answer:

v= 449.8 m/s

Explanation:

Given data

Frequency= 346Hz

Wave length= 1.4m

The expression below is used to find the speed

$v= f \lambda\\\\$

substitute

$v= 346*1.3\\\\v= 449.8 m/s$

Hence the speed is v= 449.8 m/s

5 0

3 years ago