Answer:
Part a)
Part b)
Explanation:
Force applied by the student on the box is 80 N at an angle of 25 degree
so here two components of the force on the box is given as
now in vertical direction we can use force balance for the box to find the normal force on it
now kinetic friction on the box opposite to applied force due to rough floor is given as
now the net force on the box in forward direction is given as
now the acceleration of the box is given as
Part b)
when box is pulled up along the inclined surface of angle 10 degree
now the two components of the force will be same along the inclined and perpendicular to inclined plane
now force balance perpendicular to inclined plane is given as
now the friction force opposite to the motion on the box is given as
now the net pulling force along the inclined plane is given as
now the box will decelerate and it is given as
The shortest wavelengths that you can see are experienced
as violet light, or whatever is the last color you can see on the
"blue end" of the spectrum. It's not exactly the same for all eyes.