A small metallic ball with charge 1 `mu`C and mass 0.1 mg, when thrown in an upward direction with initial velocity u, comes to rest after covering a distance of 5 cm in a uniform external electric field of strength `2.8xx10^6 NC^(-1)` . Find the value of u.

Explanation

To find the initial velocity \( u \) of a small metallic ball with charge \( 1 \, \mu C \) and mass \( 0.1 \, mg \) that comes to rest after covering a distance of \( 5 \, cm \) in a uniform electric field of strength \( 2.8 \times 10^6 \, N/C \), we can follow these steps:

### Step 1: Convert Units
Convert the mass and distance into standard SI units.
- Mass: \( 0.1 \, mg = 0.1 \times 10^{-3} \, g = 0.1 \times 10^{-6} \, kg = 1 \times 10^{-7} \, kg \)
- Distance: \( 5 \, cm = 5 \times 10^{-2} \, m \)

### Step 2: Identify Given Values
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