IMAT 2014 Q53 [Acceleration]

A book of mass 0.40 kg rests on a horizontal surface with which it has a coefficient of dynamic friction of 0.50.

If this book is now pushed by an external horizontal force of 10 N, what will be its acceleration immediately after it has started to move?

[Assume the gravitational field strength is 10 Nkg­^{-1}, that air resistance is negligible and that the orientation of the book does not change.]

A. 25.0 ms^{-­2}
B. 12.5 ms^{-­2}
C. 50.0 ms^{-­2}
D. 20.0 ms^{-­2}
E. 15.0 ms^{-­2}