1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
rewona [7]
3 years ago
9

Two point charges of -7uC and 4uC are a distance of 20

Physics
2 answers:
aivan3 [116]3 years ago
8 0

Answer:

Approximately 0.979 J.

Explanation:

Assume that the two charges are in vacuum. Apply the coulomb's law to find their initial and final electrical potential energy \mathrm{EPE}.

\displaystyle \mathrm{EPE} = \frac{k \cdot q_1 \cdot q_2}{r},

where

  • The coulomb's constant k = 8.99\times 10^{9}\; \rm N\cdot m^{2} \cdot C^{-2},
  • q_1 and q_2 are the sizes of the two charges, and
  • r is the separation of (the center of) the two charges.

Note that there's no negative sign before the fraction.

Make sure that all values are in SI units:

  • q_1 = -7\rm \;\mu C = -7\times 10^{-6}\; C;
  • q_2 = 4\rm \;\mu C = 4\times 10^{-6}\; C;
  • Initial separation: \rm 20\; cm = 0.20\; cm;
  • Final separation: \rm 90\; cm = 0.90\; cm.

Apply Coulomb's law:

Initial potential energy:

\begin{aligned} \frac{k \cdot q_1 \cdot q_2}{r} &= \frac{8.99\times 10^{9}\times (-7\times 10^{-6})\times 4\times 10^{-6}}{0.20}\\&= \rm -1.2586\; J\end{aligned}.

Final potential energy:

\begin{aligned} \frac{k \cdot q_1 \cdot q_2}{r} &= \frac{8.99\times 10^{9}\times (-7\times 10^{-6})\times 4\times 10^{-6}}{0.90}\\&= \rm -0.279689\; J\end{aligned}.

The final potential energy is less negative than the initial one. In other words, the two particles gain energy in this process. The energy difference (final minus initial) will be equal to the work required to move them at a constant speed.

\begin{aligned}\text{Work required} &= \text{Final EPE} - \text{Initial EPE}\\&= \rm  -0.279689\; J - (-1.2586\; J)\\&\approx 0.979\; J\end{aligned}.

olga2289 [7]3 years ago
3 0

Answer:

Answer is c

Explanation:

trust me.

You might be interested in
The band gab of semi conductor?
Lerok [7]

Answer:

Properties of semiconductors are determined by the energy gap between valence and conduction bands. To understand, what is semiconductor, we have to define these terms. In solid-state physics, the energy gap or the band gap is an energy range between valence band and conduction band where electron states are forbidden.

8 0
3 years ago
Two scientists interpret the same set of data differently. How would the scientific community deal with this problem?
alexdok [17]
The correct answer would be D. A new experiment would be needed to be done in order to test the conclusions. In science there is no authority, data is the only thing that matters. So if we have two different conclusions from the same date the only solution is to perform more tests and more experiments to see what is correct.
7 0
3 years ago
Two tuning forks of frequency 480 hz and 484 hz are struck simultaneously. what is the beat frequency resulting from the two sou
umka21 [38]
Ans: Beat frequency = f_b = 4Hz

Explanation: 
The beat frequency is equal to the absolute value of the difference in frequency of the two waves. In other words, the number of beats per second is equal to the difference in frequency. It is due to the destructive and constructive interference. <span>According to this interference, sound will be soft or loud.

Hence. the formula is:
</span>Beat frequency = f_b = |f_2 - f_1|
<span>
Since,
</span>f_1 = 480Hz
f_2 = 484Hz

Therefore,
Beat frequency = f_b = |484 - 480|

=> Beat frequency = f_b = 4Hz
-i
7 0
3 years ago
How much force is required to raise a 0.2 kg mass?
Firlakuza [10]

Answer:

1.96 N

Explanation:

6 0
2 years ago
Read 2 more answers
Please help only have a short amount of time left!
VARVARA [1.3K]

Answer:

I think all will display the same value

Explanation:

Sorry if this is wrong

6 0
2 years ago
Read 2 more answers
Other questions:
  • Fill in the blanks with the terms that complete the sentences about nuclear power plants. Without a critical of fissionable mate
    11·2 answers
  • An electron that has a velocity with x component 1.6 × 106 m/s and y component 2.4 × 106 m/s moves through a uniform magnetic fi
    7·1 answer
  • Electromagnetic induction is the production of a voltage across a conductor when it is exposed to a varying magnetic field. This
    13·2 answers
  • Need asap !
    5·2 answers
  • you read about a rope and pulley machine that was able to produce equal amounts of output work and input work.was this a realist
    15·2 answers
  • When a piano tuner strikes both the A on the piano and a 440 Hz tuning fork, he hears a beat every 2 seconds. The frequency of t
    7·1 answer
  • Would an astronauts mass change as she traveled from planet to planet? Explain.
    15·1 answer
  • ___________is the tendency of an object to resist change in its state of motion
    8·1 answer
  • Which of the following is true of an adiabatic process?
    15·2 answers
  • Which tricks do you use to reduce pressure in everyday activities? Which tricks do you use to reduce pressure in everyday activi
    8·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!