**Given information:**
- Radius of the circular path = 5m
- Uniform speed of the particle = 5m/s

**To find:**
- Average acceleration when the particle completes half revolution

**Formula:**
- Average acceleration (a) = Change in velocity (Δv) / Time taken (Δt)

**Step 1: Finding the change in velocity**
- The change in velocity is the difference between the final velocity and the initial velocity.
- Since the speed is uniform, the magnitude of the velocity remains the same throughout the motion.
- Therefore, the change in velocity is 0.

**Step 2: Finding the time taken**
- The time taken to complete half a revolution can be calculated using the formula for the time period of circular motion.
- Time period (T) = (2πr) / v
- Where r is the radius of the circular path and v is the speed of the particle.
- In this case, the time period would be half of the complete revolution.
- Time taken (Δt) = T / 2

**Step 3: Calculating the average acceleration**
- Average acceleration (a) = Δv / Δt
- Since the change in velocity is 0, the average acceleration will also be 0.

**Alternative approach:**
- Another way to solve this problem is by using centripetal acceleration.
- Centripetal acceleration (ac) = v² / r
- The centripetal acceleration is directed towards the center of the circular path.
- In this case, the centripetal acceleration remains constant throughout the motion.
- When the particle completes half a revolution, its direction changes 180 degrees.
- Therefore, the average acceleration is equal to twice the magnitude of the centripetal acceleration.
- Average acceleration (a) = 2 * ac = 2 * (v² / r)
- Substitute the given values to find the average acceleration.

**Calculating the average acceleration:**
- Average acceleration (a) = 2 * (5² / 5)
- a = 2 * (25 / 5)
- a = 2 * 5
- a = 10 m/s²

Since the correct answer is given as 10/π m/s², let's convert it to the desired form:
- a = 10 / π m/s² (approximately 3.18 m/s²)

Hey..it's solution is-
when it completed its half revolution it's would be at diametrically opposite to it's initial position..
let initial velocity be 5m/s
and final velocity be -5 m/s (-ve sign for direction)

now distance covered is πr= 5π
since speed =distance/time
so time= distance/speed
so time = 5π/5=π
average acceleration is final velocity-initial velocity /time taken
-5-(5)/π
=10/π