The magnitude of the second charge needed to propel the first charge is 6,250 C.
The magnitude of the second charge is calculated by applying Coulomb's law as follows;
F = kq₁q₂/r²
where;
Fr² = kq₁q₂
q₂ = Fr²/kq₁
q₂ = (100 x 750,000²)/(9 x 10⁹ x 1)
q₂ = 6,250 C
Thus, the magnitude of the second charge needed to propel the first charge is 6,250 C.
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