I honestly have no idea what to do. I have a general idea, but i'm not getting the second part of the question right. please help!
Two blocks of masses of 40.0 kg and 20.0 kg are stacked on a table with the heavier block on top. The coefficient of static friction is 0.600 between the two blocks and 0.300 between the bottom block and the table. A horizontal force is slowly applied to the top block until one of the blocks moves. (a) Where does slippage occur first: between the two blocks or between the bottom block and the table? Explain. (b). What value of the coefficient of static friction between the bottom block and the table would change the answer to part (a) ?
Two blocks of masses of 40.0 kg and 20.0 kg are stacked on a table with the heavier block on top. The coefficient of static friction is 0.600 between the two blocks and 0.300 between the bottom block and the table. A horizontal force is slowly applied to the top block until one of the blocks moves. (a) Where does slippage occur first: between the two blocks or between the bottom block and the table? Explain. (b). What value of the coefficient of static friction between the bottom block and the table would change the answer to part (a) ?
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(40 + 20) = 60kg.
(60 x 9.8) = 588N. weight.
Force to move both blocks on table = (588 x .3) = 176.4N.
Now find force to move the top block on the bottom one.
(40 x 9.8) = 392N.
(392 x .6) = 235.2N.
a) So both blocks will start moving on the table first, as that requires the least force.
b) Minimum friction force to change result = 235.2N.
New coefficient = (235.2/588) = 0.4.
(60 x 9.8) = 588N. weight.
Force to move both blocks on table = (588 x .3) = 176.4N.
Now find force to move the top block on the bottom one.
(40 x 9.8) = 392N.
(392 x .6) = 235.2N.
a) So both blocks will start moving on the table first, as that requires the least force.
b) Minimum friction force to change result = 235.2N.
New coefficient = (235.2/588) = 0.4.