...UNIT 2 FRICTION Structure 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 Introduction Objectives Friction Types of Friction Laws of Dry Friction Static and Kinetic Friction Coefficient of Friction Angle of Repose Least Force Required to Drag a Body on a Rough Horizontal Plane Horizontal Force Required to Move the Body Screw and Nut Friction 2.10 Self-Locking Screws 2.11 Condition for Maximum Efficiency 2.12 Screw Jack 2.13 Pivot and Collar Friction 2.13.1 Flat Pivot 2.13.2 Conical Pivot 2.13.3 Collar Bearing 2.14 Clutch 2.15 Types of Clutches 2.15.1 Conical Clutch 2.15.2 Single Plate Clutch 2.15.3 Multi Plate Clutch 2.16 Journal Bearing 2.17 Rolling Friction 2.18 Ball and Roller Bearings 2.19 Summary 2.20 Key Words 2.21 Answers to SAQs 2.1 INTRODUCTION When a body moves or tends to move on another body, a force appears between the surfaces. This force is called force of friction and it acts opposite to the direction of motion. Its line of action is tangential to the contacting surfaces. The magnitude of this force depends on the roughness of surfaces. In engineering applications friction is desirable and undesirable. We can walk on the ground because of friction. Friction is useful in power transmission by belts. It is useful in appliances like brakes, bolts, screw jack, etc. It is undesirable in bearing and moving machine parts where it results in loss of energy and, thereby, reduces efficiency of the machine. In this unit, you will study screw jack, clutches and...
Words: 6929 - Pages: 28
...Essay: R.J. Reynolds International Financing (HBS 9-287-057). Page 1 of 7 "Cour sew or k.Info offer s a ver y valuable tool to students." Dr Yaakov Wise, Univer sity of M anchester LO G I N JO I N N O W ! SEARCH Adv anced search Search Coursew ork .info You a re he re : Universit y > Business and Adm inist rat iv e st udies > Finance > R.J. Reynolds I nt er nat ional Financing ( HBS 9- 287- 057) . N O M ORE BRAI N FREEZE - j ust love ly ide a s j uice ! W e 've got 1 ,4 6 2 GCSE Gr e e n Pla n t s a s Or ga n ism s Essa ys on lin e r ig h t n ow t o in sp ir e you St udy t he w ork of t he bright est st u den t s in t h e u k , a ll for le ss t h a n 1 7 p a da y. Accoun t ing ( 513 Essays) Econom ics (1,080 Essays) Fina nce ( 1, 083 Essays) H um a n Re sour ce M a na ge m e nt ( 1,012 Essays) M a na ge m e nt St udie s ( 1, 723 Essays) - I n t e r n a t ion a l Fin a n cia l R.J. Rey nolds I nt er nat ional Financing ( HBS 9- 287- 057) The case is set in t he cont ext of RJR’s 1985 financing of it s $4.9 billion acquisit ion of Nabisco Brands I nc. To finance t he acquisit ion, RJR was pr oposing t he issue of $1.2 billion of 12 year not es and t he sam e am ount in pr efer r ed st ock . I t had alr eady funded $1.5 billion of t he acquisit ion leav ing $1 billion m or e t o finance. Challenges facing RJR: Of t he $1.5 billion t hat had been funded, $500 m illion cam e from cash and t he r em aining was t hr ough bank bor r owings and...
Words: 4457 - Pages: 18