Answer:

Explanation:
The process during which pressure remains constant is called an isobaric process.
Use the definition of average acceleration:
<em>a</em> = ∆<em>v</em> / <em>t</em>
If <em>v</em> is the starting speed, then ∆<em>v</em> = 0 - <em>v</em>, so solve for <em>v</em> :
-6.42 m/s² = (0 - <em>v</em>) / (2.85 s)
<em>v</em> = (6.42 m/s²) (2.85 s)
<em>v</em> ≈ 18.3 m/s