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.

 

[Moetasim]

1. To determine the coefficient of friction with only acceleration as a given variable, you can use the equation F = ma, where F is the force of friction, m is the mass of the object, and a is the acceleration. By rearranging the equation to solve for the coefficient of friction, you can use the given acceleration and the known mass of the object to calculate the coefficient of friction. However, this method assumes that there are no other forces acting on the object, such as an external force or air resistance. If these forces are present, they will affect the acceleration and therefore may affect the calculated coefficient of friction.

2. Yes, a force applied on top of a box sitting on an inclined ramp can make it move. The direction of the applied force must be greater than the force of friction acting on the box in order for it to move. As the force is applied perpendicular to the ramp, it will create a component of force parallel to the surface of the ramp, which will overcome the force of friction and cause the box to move. However, the angle of the ramp and the magnitude of the applied force will also play a role in determining the amount of force needed to move the box.