roblem 7.39 Part A Figure shows a block of mass m resting on a 20° slope. The bl
ID: 1790451 • Letter: R
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roblem 7.39 Part A Figure shows a block of mass m resting on a 20° slope. The block has ooeflientsoffriction :082 and "0.53 with the surface. It is connected via a massless string over a massless frictionless pulley to a hanging block of mass 2.0 kg. Figure 1) What is the minimum mass m that will stck and not slip? Express your answer to three significant figures and include the appropriate units. mValueUnits Submit My Answers Give Up Part B If this minimum mass is nudged ever so sighty, it will start being pulled up the incline. What acceleration will t have? Express your answer to three significant figures and include the appropriate units a Value Units Submit My Answers ateUp Figure 1 of 1 20° 2 kgExplanation / Answer
here,
theta = 20 degree
us = 0.82 , uk = 0.53
a)
as the accelration is zero
a = net force /effective mass
0 = ( 2 * g - m * g * sin(theta) - us * m * g * cos(theta)) /(m + 2)
0 = ( 2 - m *sin(20) - 0.82 * m *cos(20))
solving for m
m = 1.8 kg
b)
for the block to just move
we use the cofficient of kinetic friction
accelration , a = net force /effective mass
a = ( 2 * g - m * g * sin(theta) - uk * m * g * cos(theta)) /(m + 2)
a = ( 2 * 9.81 - 1.8 * 9.81 * sin(20) - 0.53 * 9.81 * cos(20)) /(1.8 + 2) m/s^2
a = 2.29 m/s^2
the accelration is 2.29 m/s^2
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