Mary applies a force of 70 N to push a box with an acceleration of 0.58 m/s². When she increases the pushing force to 77 N, the box's acceleration changes to 0.78 m/s². There is a constant friction force present between the floor and the box.

What is the mass of the box in kilograms?

What is the coefficient of kinetic friction between the floor and the box?

As shown in the figure below, a 2.45 kg block is released from rest on a ramp of height h. An illustration shows a block positioned a height h at the top of the vertical portion of a curved ramp. The ramp is oriented such that it curves downward from right to left, starting from an almost-vertical slope and then decreasing in slope magnitude until it is horizontal. The ramp is frictionless except for a horizontal 15.0 cm section at the bottom of the curve. When the block is released, it slides without friction to the bottom of the ramp, and then continues across a surface that is frictionless except for a rough patch of width 15.0 cm that has a coefficient of kinetic friction. _k=0.540. Find h (in m) such that the block's speed after crossing the rough patch is 4.30m/s.

rough patch wwww 15.0 cm