Answer to Question #184527 in Field Theory for Charles

Question

If two block with masses 5kg and4kg connected by a string are placed on a horizontal table and are pulled by a force of 30N calculate the tension in the string if frictional force is negligible.Repeat the problem if the coefficient of kinetic friction between the blocks an the table is 0.3N

Answer 1

1)

$$(5+4)a=30\\T=4a=4\frac{10}{3}=13.3\ N$$

2)

$$(5+4)(a+0.3(9.8))=30\\T=4a=4(0.393)=1.57\ N$$