HINTS RELATIVE TO FRICTION, ScC a I7I 



VI. 



HINTS 



RELATIVE TO 



FRICTION IN MECHANICS. 



By Mr. REUBEN BURROW, 



HYPOTHESIS. 



IN the following eftimation of friction, the weight or 

 force neceffary to overcome the refiftance, &c. is 

 fuppofed to be proportional to the prefifure. 



Of FRICTION in the INCLINED PLANE. 



Let AB bean inclined plane,* and let PR reprefent 

 a weight fuftained on it by any force Rm, acting in the 

 direction Rm : and draw PD perpendicular to AB, and 

 let Rm meet PD in n : Now as Rn reprefents the force 

 that would be neceffary to fuftainthe body, exclufiveof 

 friction, and Pn reprefents the preffure againft the 

 plane, if mt be drawn perpendicular to PD meeting it 

 in t, then will nm be the force neceffary to overcome 

 the friclion in that direction, and Pt the real preffure 

 againft the plane AB, when the whole force Rm, necef- 

 fary to overcome both the weight and the friction, acts in 

 the direction Rm; and as the force nm is equivalent to 

 nt and tm, and nt has no other effect than to alter the 

 preffure, therefore tm is the only force which overcomes 

 the refinance of friction ; and as this force is as the 

 preffure, therefore tm is proportional to Pt, and hence 

 the locus of all the points m is a right line. 



O 2 Again } 



* Fig. I, 



