Relatively simple friction problem

[flower76]

Ok, I've done an experiment in which the coefficient of kinetic friction was measured by measuring the acceleration of an object moving down an incline. The mathematical relationship is: a=gsin(theta)-ukgcos(theta)

The question is that I found a slight increase in uk as the incline angle increased. And I don't know how to explain this. I was thinking that since the net force and acceleration are directly related, an increase in net force will see an increase in kinetic friction, since friction acts due to the net force.

Can anyone confirm or deny what I have said??

 

[whozum]

The friction force should increase as the slope gets flatter. This is because at a much smaller incline, the normal force on the object has a much larger component of gravity bearing on it.

 

[thepatientmental]

Your explanation is correct. As the incline angle increases, the component of the weight of the object acting down the incline also increases. This results in a greater net force acting on the object, leading to a higher acceleration down the incline. Since the acceleration and the coefficient of kinetic friction are directly related, the increase in acceleration would also result in an increase in the coefficient of kinetic friction. This is because the object is experiencing a greater force due to the incline angle, causing more resistance from the surface it is moving on. So, your observation of a slight increase in uk as the incline angle increases is expected and can be explained by the relationship between net force, acceleration, and coefficient of kinetic friction.