A student moves a 25kg box of books up a ramp inclined at 10° with the horizontal by pulling a rope attached to the box. The student pulls the rope with a force of 120N at an angle of 30° relative to the ramp.
a. Find the normal force of the block.
b. Calculate the force of friction between the box and the ramp if the coefficient of kinetic friction between the box and the ramp is 0.2
2006-12-07 08:25:07 · 1 answers · asked by Some Guy 2 in Science & Mathematics ➔ Physics
a N=W' cos (10)
The effective weight of the block is reduced by student moving the block up the inclined. The relative angle is 30 less the incline of 10 degrees.
W'=W-Fsin(30-10)=
W'=25(9.81)-120 sin(20)=
W'=245.25-41.04=
W'=204.21N
N=204.21 cos(10)=201.1N
b. f=uN
f=(.2)(201.1)=40.22N
2006-12-07 09:23:11 · answer #1 · answered by Edward 7 · 0⤊ 0⤋