Physics 11  Dynamics
posted by Samuel .
While standing on a horizontal frictionless surface a 50.0 kg student pushes against a wall with an average force of 125 N to the right for 0.110 s. Calculate the velocity of this student at 1.110 s.
My answer: Vf = 0.275 m/s
My solutions book has Vf = 0.275 m/s OR 0.275 m/s to the left.
My question is where does the negative or the "to the left" come from? My understanding is that "right" is positive.
Thanks.

250 kg•m/s