A force of 20N applied parallel to the surface of a horizontal table is just sufficient to make a block of mass 4kg move on the table Calculate the coefficient of friction

Physics Jamb, Waec, Neco Past Questions & Answers on FRICTIONAL FORCE

QUESTIONS 1. A force of 20N applied parallel to the surface of a horizontal table is just sufficient to make a block of mass 4kg move on the table Calculate the coefficient of friction 

between the block and the table (g=10m/s2). Ans: 0.5 

WAEC 1992

Solutions 

Frictional force F = 20N

Mass m =4kg

Coefficient of friction u => ?

Using u = F/R

R = W = mg = 4 x 10 = 40N

u = F/R 

u = 20/40

u = 2/4

u = 0.5