Calculating Coefficient of Friction: Newton's 3rd Law Examples

[honeycoh]

1.) a 50kg block is being pulled at a constant speed along a horizontal surface by a horizontal force of 120N.

Q: what is the coefficient of kenetic friction?

2.) a 100kg wooden crate is being pushed across a wooden floor with a horizontal force of 350N.
Q: What is the net force acting on a crate?

3.) A cabinet weighing 400N is pulled along a horizontal floor at constant speed by a rope which makes an angle of 30 degrees with the floor.

Q: what is the coefficient of sliding friction if the force on the rope is 220N?



Thanks in advance...

 

[aniketp]

Could you show what solving strategy you have applied here?