Physics lab report the ramp

i need help with a lab report...

i already calculated

Cabinet: Mass 100 kg Usmax 0.3 Ramp Angle 10 degree.. actual force needed 460.11 N.. Difference from calculated force: 0.0

Regrigerator: Mass 175 kg Usmax 0.5 Ramp Angle 10 degree.. actual force needed 1715.33 N.. Difference from calculated force: 0.0

Piano: Mass 225kg kg Usmax 0.4 Ramp Angle 10 degree.. actual force needed 2205.56 N.. Difference from calculated force: 0.0

Itchy: Mass 15 kg Usmax 0.1 Ramp Angle 10 degree.. actual force needed 147.27 N.. Difference from calculated force: 0.0


Question for lab report (This is where i need help)

1 Why was the actual force needed different from your calculated force?
2. What happened to the velocity of the object as it move up the ramp? why did this happen?
3. How would changing the angle change the force needed to push the item up the ramp?
4. determine the acceleration of each item up the ramp?

I will not answer the questions here...........but.............a more salient question is " How on earth did the calculated forces agree to the actual forces to within up to six significant figures ?"..............something does not seen right, and an explanation would be valuable.

I'm not criticizing, just baffled.