Question

A block of mass 0.8kg is dragged along a level surface at constant velocity by hanging block of mass 0.2 kg

Answer 1

since both blocks are connected together and dragged with constant velocity

So the acceleration of two blocks will be zero

so we can say

force on two blocks will be balanced

for hanging block of mass 0.2 kg

$T = mg$

$T = 0.2* 10 = 2 N$

now for another block placed on table of mass 0.8 kg

Tension force is counter balanced by friction force due to table

$T = F_f$

$T = \mu*m g$

now we have

$T = \mu*0.8*10 = 10\mu$

now from above equations we can say

$2 = 10 \mu$

$\mu = 0.2$

so the friction coefficient on the table must be 0.2