Remote Control Overhanging Table

[proace360]

Homework Statement

A 0.090 kg remote control 24.2 cm long rests on a table, as shown in the figure below, with a length L overhanging its edge. To operate the power button on this remote requires a force of 0.460 N. How far can the remote control extend beyond the edge of the table and still not tip over when you press the power button? Assume the mass of the remote is distributed uniformly, and that the power button is on the end of the remote overhanging the table.

Homework Equations

Torque=Nr

The Attempt at a Solution

I made the FBD, but I can't figure out how to implement the Normal force into my torque equation. It screws with my results!

 

[PhanthomJay]

Homework Statement

A 0.090 kg remote control 24.2 cm long rests on a table, as shown in the figure below, with a length L overhanging its edge. To operate the power button on this remote requires a force of 0.460 N. How far can the remote control extend beyond the edge of the table and still not tip over when you press the power button? Assume the mass of the remote is distributed uniformly, and that the power button is on the end of the remote overhanging the table.

Homework Equations

Torque=Nr

The Attempt at a Solution

I made the FBD, but I can't figure out how to implement the Normal force into my torque equation. It screws with my results!

The normal force (like a see-saw) acts at the table edge when the remote is just about to tip. Sum torques about the edge of table; the Normal force won't enter into the equation when you sum torques about it. Don't forget the torque produced by the weight of the remote.

 

[proace360]

Why is it at the edge of the table? Wouldn't it be in the middle of the remote?

 

[PhanthomJay]

Why is it at the edge of the table? Wouldn't it be in the middle of the remote?

The normal force occurs over the contact area between the remote and table; when the remote is just on the verge of tipping over, that contact is now just over one point: the table edge.