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Elenna [48]
3 years ago
6

Electromagnets can be used to lock doors. How could an engineer increase the strength of an electromagnetic lock? Check all that

apply
A. by increasing the current through the wire

B. by reversing the current through the electromagnet

C. by adding more coils to the electromagnet

D. by increasing the space between the coils in the electromagnet
Physics
1 answer:
ddd [48]3 years ago
3 0

The answer should be A

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Two neutron stars are separated by a distance of 1.0 x 1012 m. They each have a mass of 1.0 x 1028 kg and a radius of 1.0 x 103
son4ous [18]

To develop this problem it is necessary to apply the concepts related to Gravitational Potential Energy.

Gravitational potential energy can be defined as

PE = -\frac{GMm}{R}

As M=m, then

PE = -\frac{Gm^2}{R}

Where,

m = Mass

G =Gravitational Universal Constant

R = Distance /Radius

PART A) As half its initial value is u'=2u, then

U = -\frac{2Gm^2}{R}

dU = -\frac{2Gm^2}{R}

dKE = -dU

Therefore replacing we have that,

\frac{1}{2}mv^2 =\frac{Gm^2}{2R}

Re-arrange to find v,

v= \sqrt{\frac{Gm}{R}}

v = \sqrt{\frac{6.67*10^{-11}*1*10^{28}}{1*10^{12}}}

v = 816.7m/s

Therefore the  velocity when the separation has decreased to one-half its initial value is 816m/s

PART B) With a final separation distance of 2r, we have that

2r = 2*10^3m

Therefore

dU = Gm^2(\frac{1}{R}-\frac{1}{2r})

v = \sqrt{Gm(\frac{1}{2r}-\frac{1}{R})}

v = \sqrt{6.67*10^{-11}*10^{28}(\frac{1}{2*10^3}-\frac{1}{10^{12}})}

v = 1.83*10^7m/s

Therefore the velocity when they are about to collide is 1.83*10^7m/s

7 0
3 years ago
If a positive test charge is placed in an electric field, what is the direction of the force on the test charge?
svetlana [45]

Explanation:

If a positive test charge is placed in an electric field, it will exert the force in the test charge in the direction of electric field vector. We know that the direction of electric field is given by electric field lines. The field lines for a positive charge is outwards. The electric force acting on the charge is given by :

F = q E

Hence, this is the required solution.

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Finger [1]
The specific heat of water is 4.186.
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Một chất điểm chuyển động tròn đều trên một cung tròn bán kính 40 cm. Biết chất điểm đi được 5 vòng trong thời gian là 2 s. Tính
Reika [66]

Nerozumím Tvůj Otázky

Explanation:

Im sorry

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3 years ago
If an object is thrown in an upward direction from the top of a building 1.6 x 10^2 ft. high at an initial velocity of 21.82 mi/
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If an object is thrown in an upward direction from the top of a building 1.60 x 102 ft. high at an initial velocity of 21.82 mi/h, what is its final velocity when it hits the ground? (Disregard wind resistance. Round answer to nearest whole number and do not reflect negative direction in your answer.)


this question is troubling me i guessed 96 ft/s

can someone help me out and explain it thanks so much!!!!!!



7 0
3 years ago
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