A puck of mass 30g slides across rough ice, experiencing a frictional force of 0.2N. If it was moving at 10 km/h when it hit the ice patch,

a) how long did it take to stop?

i first calculated the acceleration of the puck and i got 6.66m/s^2. then i determined the time and i got 1.5 s

b) how long was the ice patch?

i used the time calculated in part a and got the answer 2.08m

please help...i thought this was a simple question but my answers do not reflect the answer key in the textbook...