208 Captain Noble on the Pressure required to 



15. The angles which the normal to this surface make with 

 the coord inate axes are given by 



cos X= 



\dx) 



with similar expressions for cos /i and cos v. But 



(s)- m d- s )< (f )--(£- s ) ; (f )-¥'"» s ; 



Therefore the angles which the normal to the driving-surface 

 makes with the axes are given by 



k . cos 



cosX= 



KT« => \ 



^43r 9 "(sin8)« + ifc« 



& .sin f — 



cos fi: 



gh 



cos v= 



V4s 2 (sin8) 2 + &' 



2z . sin 3 



^4^ 2 (sinS) 2 + ^ 'j 



(9) 



16. Substituting in (2) and (3) the values given for a, (3 } y, 

 X, p., v in (5) and (9), the equations of motion become 



M 



d*z 



dt 2 



W4* 2 (sinS)*-fyfc 2 ^ V^T¥S } ' v ^ 





and from (11), 



M.p 2 



17. To determine -r-f 



f A;, sin 6 ^ "Zfjb^ 



\y4^ki8^+F V4>z 2 + k 2 



d*$ 



v 



-t (121 



