Question

A 5 kg block lies on a rough horizontal surface. The coefficient of static friction μs = 0.22. It is connected to another 3 kg block by a string that passes a frictionless pulley as shown in the figure below. 

a. Find the unbalanced force, b. Find the acceleration of the blocks, and c. Find the tension T in the string

Answer 1

$mg-T=ma$

$T-\mu Mg=Ma$

$3g-T=3a$

$T-0.22\cdot5\cdot g=5a$

$T=3g-3a$

$3g-3a-0.22\cdot5\cdot g=a \to a=(3g-0.22\cdot5\cdot g)/4=$

$=(3\cdot9.8-0.22\cdot5\cdot 9.8)/4=4.67\ (m/s^2)$ . Answer

$T=3\cdot9.8-3\cdot4.67=15.4\ (N)$ . Answer

$F_{unb1}=15.4-0.22\cdot 5\cdot9.8=4.62(N)$

$F_{unb2}=3\cdot9.8-15.4=14(N)$ . Answer