Question
Three blocks of masses 3m, 2m, ands are connected to strings A, B, and C as shown above. The blocks are pulled along a rough surface by a force of magnitude Fexerted by string C. The coefficient of friction between each block and the surface is the same. Which string must be the strongest in order not to break? 2m A. they must al be the same strength it is impossible to determine without knowirg the cocffiecient of friction Question 14 5.2631579 pts An abject weighing 300 N is suspended by means of two cords, as shown above. The
Explanation / Answer
mAa = Ta - umAg
mBa = TB - TA - umBg
mAa = F - TB - umCg
F = (mA + mB + mC)a = 6ma
then
a = F/(6m)
TA = mAa + umAg = 1/2F + 3umg
TB = Ta + mBa + umBg = 1/2F + 3umg + 1/3F + 2umg = 5/6F
TC = F = TB + mAa + umAg = 5/6F + 5umg + F/6 + umg = F + 6u
then
TC > TB > TA
the correct answer is C