At the airport, you pull a 20 kg suitcase across the floor at constant velocity with a strap that
is at an angle of 45° above the horizontal. Find the normal force on the suitcase, given that
the coefficient of kinetic friction between the suitcase and the floor is 0.25

Question

At the airport, you pull a 20 kg suitcase across the floor at constant velocity with a strap that 
is at an angle of 45° above the horizontal. Find the normal force on the suitcase, given that 
the coefficient of kinetic friction between the suitcase and the floor is 0.25

anonymous · Answer

|dw:1392429026406:dw|
u is coefficient of friction
Since it moves with constant velocity, net Force=0.
in horizontal direction,
Fcos45-umg=0
gives $$F=50\sqrt{2}$$ In vertical direction,
Fsin45 + Normal reaction= mg
solving gives Normal reaction = 150N