Answer: 8 * 10⁻⁸ cm² .
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Explanation:
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(2 * 10⁴ cm) * (4 * 10⁻¹² cm) =
2 *4 * 10⁴ * 10⁻¹² = 8 * 10⁽⁴⁺⁽⁻¹²⁾⁾ = 8 * 10⁻⁸ cm² .
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Note the follow property of exponents:
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xᵃ * xᵇ = x⁽ᵃ ⁺ ᵇ⁾ ; as such: " 10⁴ * 10⁻¹² = 10⁽⁴⁺⁽⁻¹²⁾⁾ = 10⁻⁸ " .
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<h2>Hello!</h2>
The answer is: Coulomb's law equation.
<h2>Why?</h2>
The Coulomb's law states that the strength of an electric field (between two charges) can be calculated by multiplying their charges and dividing it into the square of the distance between their centers.

Where:
E = Electric Field Strenght


d = separation between charges (m)
Have a nice day!
Answer:
Work done by the little rocket engine = 19.6 Joules.
Explanation:
We know that work = force x displacement.
Force = weight of rocket = 4.9 N
Displacement = 5 meter.
So work done by the little rocket engine = Weight of rocket x displacement.
Work done by the little rocket engine = 4.9 x 4 = 19.6 J
Work done by the little rocket engine = 19.6 Joules.