Consider the situation as shown in the figure. A constant horizontal force 45 N acting on the lower blocks produces an acceleration `4(m)//(s^2)`, the two blocks always move together. Find (a) coefficient of friction between the bigger block and the horizontal surface (b) friction acting on the upper block and (c ) work done by the friction on the upper block during a displacement 2m of the system.

Explanation

(a) `N_0=50N`,`f=muN_0=50mu`,`F=45N`
For system of blocks,
`F-f=(2+3)a`
`45-50mu=5a=5xx4`
`mu=(1)/(2)`
(b) Upper blocks `2kgrarra=4(m)/(s^2)`
`f^(')=2a=2xx4=8N`
(c ) `W=f^(')d=8xx2=16J`