STATIC FRICTION:

The friction force pushing back against the attempted motion before the stacked objects move is due to static friction, and that force is: Ffs??sN. Whatever magnitude of force you found that caused the objects to begin to move is JUST BARELY larger than the maximum static frictional force that can hold the stacked objects in place while the robot is pushing against them. Subtract 1N from that pushing force you found which started the stack moving and estimate this value as the magnitude of your maximum F_fs.

This maximum static frictional force is equal to ?sN, where the normal force N = mg (which we know since the stacked objects are in static equilibrium in the vertical direction). You noted your total mass m of your stacked objects so you can calculate the Normal force N. Use this to determine the static coefficient of friction ?s. Do same calculation for all of your experimental trials and average your results together.

KINETIC FRICTION:

The friction force while the stacked objects are in motion is kinetic friction and that force is: Ffk=?kN. Whatever force your robot pushed with that allowed the stacked objects to move with constant speed must be exactly the same magnitude as the frictional force pushing back against the stacked objects while they are moving, and thus they are in equilibrium - meaning zero acceleration, where no change in velocity is occurring - leading to a constant speed reading. That means the magnitude of the robot's force you noted that resulted in movement with constant speed is equal to the kinetic frictional force F_fk.

This kinetic frictional force is equal to ?kN, where the normal force N = mg (which we know since the stacked objects are in static equilibrium in the vertical direction). You noted your total mass mof your stacked objects so you can calculate the Normal force N. Use this to determine the kinetic coefficient of friction ?k. Do same calculation for all of your experimental trials and average your results together.

ON A PIECE OF PAPER OR ELECTRONIC DOCUMENT:

WRITE OUT YOUR DATA FOR EACH TRIAL IN A CLEAR TABLE OR LIST

SHOW YOUR CALCULATION WORK FOR DETERMINING THE STATIC COEFFICIENT OF FRICTION FOR EACH OF THE 3 TRIALS AND YOUR FINAL OVERALL AVERAGED RESULT

SHOW YOUR CALCULATION WORK FOR DETERMINING THE KINETIC COEFFICIENT OF FRICTION FOR EACH OF THE 3 TRIALS AND YOUR FINAL OVERALL AVERAGED RESULT

COMMENT ON HOW STATIC AND KINETIC COEFFICIENTS OF FRICTION TYPICALLY COMPARE TO ONE ANOTHER FOR A SINGLE SURFACE AND STATE WHETHER OR NOT YOUR RESULTS IN THIS EXPERIMENT FOLLOW THIS TREND.

UPLOAD YOUR COMPLETED WORK HERE

Data: Trial 1: ist total mass: 50+80 kq = 130 kg Applied Force to move:410N Applied Force needed to have constant speed: 380N's Trial 2: Ist total mass: 100+ 40 kg. = 140 kg Applied Force to move : 43IN Applied Force needed to have constant speed: 386N Trial 3 : Ist total mass: 80 kgtuong = 120 kg Applied Force to move: 37IN Applied Force needed to have constant speed : 353 N