A particle of charge `+7.5 mu C` is released from rest at the point `x=60 cm` on an `x` axis. The particle begins to move due to the presence of a charge `Q` that remains fixed at the origin. What is the kinetic energy of the particle at the instant it has moved 50 cm if (a) `Q= 20 mu C and (b) Q=-2 mu C?`

Explanation

To solve the problem, we will use the principle of conservation of energy. The kinetic energy gained by the particle will be equal to the change in electric potential energy as it moves from the initial position to the final position.

### Given:
- Charge of the particle, \( q = +7.5 \, \mu C = 7.5 \times 10^{-6} \, C \)
- Initial position, \( x_i = 60 \, cm = 0.6 \, m \)
- Final position, \( x_f = 50 \, cm = 0.5 \, m \)

### (a) When \( Q = +20 \, \mu C \)
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