A particle of mass 40 mg and carrying a charge `5 xx 10^(-9) C` is moving directly towards a fixed positive point charge on magnitude `10^(-8) C`. When it is at a distance of 10 cm from the fixed positive point charge it has a velocity of `50 cm s^(-1)` at what distance from the fixed point charge will the particle come momentarily to rest ? Is the acceleration constant during motion?

Explanation

To solve the problem step by step, we will apply the principle of conservation of mechanical energy.

### Given Data:
- Mass of the particle, \( m = 40 \, \text{mg} = 40 \times 10^{-6} \, \text{kg} \)
- Charge of the particle, \( q_1 = 5 \times 10^{-9} \, \text{C} \)
- Fixed positive charge, \( q_2 = 10^{-8} \, \text{C} \)
- Initial distance from the fixed charge, \( r_1 = 10 \, \text{cm} = 0.1 \, \text{m} \)
- Initial velocity, \( v_1 = 50 \, \text{cm/s} = 0.5 \, \text{m/s} \)
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