A pebble thrown vertically upwards with an initial velocity 50 m `s^(-1)` comes to a stop in 5 s. Find the retardation.

Explanation

To solve the problem of finding the retardation of a pebble thrown vertically upwards, we can follow these steps:

### Step-by-Step Solution:

1. **Identify Given Values:**
- Initial velocity (u) = 50 m/s (upwards)
- Final velocity (v) = 0 m/s (at the highest point, the pebble stops)
- Time (t) = 5 s
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