1. Two charges are 15.0 cm apart. The charges are moved so that the force between them becomes 7.0 times the original value. What is the distance between them (in cm)?
2. A person scuffs his feet on a carpet on a dry winter day, and acquires -45 microcoulombs of charge. How many extra electrons has he acquired?
3. If a person gains electrons so that the extra charge is -45 microcoulomb, how much extra mass (in kg) does he have?
4. A proton is released at a point of space containing a uniform electric field. The magnitude of the force experienced by the charge was 3.5 x 10¯¹⁴ Newtons. What is the magnitude of the electric field?
5. Two point charges, Q1 = -28 microcoulomb and Q2 = 50 microcoulomb, are separated by a distance d = 20 cm. At point P, the net electric field is 0. How far is P (in cm) from Q1 (see picture)?

x Q1 d Q2
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p

6. A capacitor has a charge of 3.0 microcoulomb and an electric field between the plates of 3.0 kV/mm. What is the area of the plates in square meters of the capacitor? (Assume that there is vacuum between the plates.)
7.How much mass (in kg) could this energy raise to a height of 75 m above the Earth's surface with the energy released from the conversion of 3.0 nanograms of mass? (Use g = 10 m/s²)

1. Two charges are 15.0 cm apart. The charges are moved so that the...