A 30 kg box is placed on a 15? slope as shown below, and a person pushes on the
ID: 1283583 • Letter: A
Question
A 30 kg box is placed on a 15? slope as shown below, and a
person pushes on the box up the slope to keep it from sliding. If
the coefficient of static friction is 0.15, what is the minimum
force that the person must exert to keep the box in place?
Explanation / Answer
sum forces along the slope
F + friction - mg sin theta = 0
friction = u N = u m g cos theta
F = m g sin theta - um g cos theta
F = 30*9.81*(sin(15 degrees) - 0.15*cos(15 degrees))= 33.5 N
5) since it has to hold up 150 N, it is 150 N so E
6) so sum forces in the y
T sin 60 - 150 = 0
t = 150/sin(60 degreeS)= 173 N
so E)