Calculate the force of friction (ff) for a 5 kg aluminum block being pulled with constant velocity (uniform motion),up a steel plank that is at a 30 degree angle to the horizontal.

24.5 N

Explanation:

Calculate the Force of Friction (Ff) for a 5 kg aluminum block being pulled with constant velocity (uniform motion),up a steel plank that is at a 30 degree angle to the horizontal.

the frictional is the force that opposes the motion of two surfaces in contact

frictional force should be balanced by one component of weight of the block along the plane.  resolving the weight to the the vertical component

∴f = mgsin30° = 5×9.8×0.5 = 24.5 N.

mass=the quantity of matter in a body 5kg

g=acceleration due to gravity m/s^2

im sorry i dont know

i think the answer is a and b

i wish you luck