A method I need to validate requires an orbital shaker with a distance of 1.2cm at 350rpm, and shakes for 15s.

The only shaker we have in the lab has an orbital shaking distance of 0.9cm and 250rpm.

My math is very rusty. I need to scale the time shaking to compensate for the slower rpm and shorter rotational distance to ensure that the mixture is still exposed to "similar" shaking conditions. If anyone can help point me in the right direction in regards to how I can figure this out mathematically that would be great.

Also, for extra information: mixture contains elastomeric closures used in drug manufacturing and the shaking in solution is to extract any extraneous particles off of the closures, so I need to ensure the closures are being exposed to similar conditions of shaking by extending the time to compensate for the slower rpm and shorter rotational distance.

Any help would be great.