Masses m1 and m2 rest on a table 1.2 meters above the floor and are attached to
ID: 2207890 • Letter: M
Question
Masses m1 and m2 rest on a table 1.2 meters above the floor and are attached to m3 via a very light string and a frictionless pulley as shown above. The coefficient of static friction between the m2 and the table is ?s = 0.18 and their coefficient of kinetic friction is ?k = 0.16. m2 = 50 kg and m3 = 25 kg.a) What is the minimum mass that m1 can have to keep the two blocks from sliding off the table?
b) m1 is completely removed. What will be the acceleration of m3? (assume up to be the positive direction).
Explanation / Answer
a)
s (m1+m2) g = m3 g
0.18*(50+m1)*9.8 = 25*9.8
>>> m1 = 88.9 Kg
b)
a = (k m2 g - m3 g)/(m2+m3) = (0.16*50*9.8 - 25*9.8)/(50+25) = -2.22 m/s2