Why does my inclined plane experiment show a ∝ m instead of a ∝ 1/m?

[Worfie]

Hello,

After collecting data for the classic physics experiment - motion down an inclined plane, I assembled my graph, and found something startling; in my graph, acceleration is proportional to mass (use the attached file for reference).

Theoretically, my graph should resemble the inverse, by a ∝ 1/m.

Can anyone explain possible reasons for this?

The experiment was running a margarine container down a wooden slope, varying the mass of the margarine container by adding brass weights each time.

 

[Orodruin]

Theoretically, my graph should resemble the inverse, by a ∝ 1/m.

What makes you think so?

 

[Worfie]

F=ma, therefore a=F/m, which implies as the mass increases, acceleration decreases.

 

[Orodruin]

What is F in your case?

 

[Worfie]

F=mg(sinθ-cosθ)

where θ is the angle of the inclined plane.

This is the net force of the block down the plane.

 

[Orodruin]

And inserting this into your expression for the acceleration gives?

Edit: you are also missing a friction coefficient...