When you pull out a stuck drawer, the force of static friction causes it to stick in place. This causes the drawer to jerk outwards, sometimes violently. Assume that you apply a constant force just large enough to “unstick” the drawer, but that when the drawer comes loose, you can’t immediately stop applying the force due to your reaction time. Estimate how far the drawer will move before it comes to rest.

How would I go about finding the the distance the drawer moves for this problem? Am I correct to assume that I need to use kinematic equations to do this? And do I need to use kinetic friction in my calculations, since the drawer would be moving?

1 answer

The "jerk" depends on the difference between static friction (the stickiness) and kinetic friction. The former is always greater than (perhaps or equal to) the kinetic friction.

You need to estimate the mass m of the drawer, the force F required to overcome the static friction, the static and kinetic frictions, and finally the reaction time.

Then you would use kinematics equations to find the acceleration of the drawer during the reaction time, and finally the time it takes for that motion to stop.