Two little questions about friction

[Mr.Barker]

1. How can you determine a coefficient of friction with only acceleration as a given variable ?
I have a problem with a book resting on a box. Both are moving at an acceleration of 3.5 m/s^2 and I need to find the smallest coefficient of static friction that will prevent slippage.

2. Will a force applied on top of a box sitting on an inclined ramp make it move? (the force is perpendicular to the ramp)

Thanks.

 

[PhanthomJay]

1. How can you determine a coefficient of friction with only acceleration as a given variable ?
I have a problem with a book resting on a box. Both are moving at an acceleration of 3.5 m/s^2 and I need to find the smallest coefficient of static friction that will prevent slippage.

2. Will a force applied on top of a box sitting on an inclined ramp make it move? (the force is perpendicular to the ramp)

Thanks.

Benjamin, welcome to PF!
If the book is accelerating, there must be a force acting on it in the direction of the acceleration, per Newton 2.. please show some attempt at a solution for both parts.