Physics acceleration?

Question

can u explain how to do this..?

A speed skater moving across frictionless ice at 10.0 m/s hits a 5.0 m wide patch of rough ice. She slows steadily, then continues on at 7.0 m/s. What is her acceleration on the rough ice?

Answer 1

2 a d = v² - vo²

a = ( 7² - 10² ) / 2 ( 5.0 m ) = -5.1 m/s²

Answer 2

She is NOT accelerating, she is DEcellerating.  And besides:  It means little to her in terms of performance.  It is a question that is spawned by an idle mind. A good skater would jump over it or skate around it.