friction & power

[barron]

case 1 Pallet supported by 4 wheels - total mass 160kg - manual force to start movement (via spring balance) 4kg
After connecting two more identical pallets force remains 4kg
case 2 Same pallet, same wheel but 10 wheels - force 1.6kg
Can mu be variable ? if so how do I apply F = m * mu to these cases
Roy

 

[FeX32]

Firstly, huh?
Of course mu is variable when you are changing the number of wheels.

Fe

 

[MikeHalloran]

The data provided, sparse as it is, suggests that seal friction at the wheel bearings governs.

You might try adding a slope to the ... floor? rails? ... whatever, something a little greater than what's anticipated when you're not around, and see what it takes to drag your pallets up a little hill.




Mike Halloran
Pembroke Pines, FL, USA

 

[chicopee]

Be careful with your equation. Friction force Ff=mu* N where N is not mass but reactive force on wheels from the floor. Your equation F=m*mu suggests m to be mass. Also coefficient of friction mu remains the same regardless of the number of wheels however you have to take into account rolling friction of the wheel bearings which you did not.