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  1. W

    Undetermined coefficient (y'' + 4y) = (x^2) +2

    i have attached the working in the picture uploaded above
  2. W

    Center of gravity vs center of buoyancy

    can you show me where is the r for the FB to generate restoring moment and overturning moment in the diagram ? so that i can understand better what you said
  3. W

    Undetermined coefficient (y'' + 4y) = (x^2) +2

    i have redo the question , i got Acos2x + Bsin2x +0.25x^2 + 3/2 , but the ans given is Acos2x + Bsin2x +0.25x^2 +3/8
  4. W

    Undetermined coefficient (y'' + 4y) = (x^2) +2

    then , what is the correct yp ? i choose my initial yp = cX^2 + Dx + E , nut i found that the term E is similar to the A , so i multiply the initial yp with x , to get my new yp
  5. W

    Undetermined coefficient (y'' + 4y) = (x^2) +2

    Homework Statement i gt stucked here ... how to continue ? what's wrong with my working ? i found 2 values for D , whcih is wrong Homework Equations The Attempt at a Solution
  6. W

    Center of gravity vs center of buoyancy

    Homework Statement when the ship is tilted more , the ship will become inclined more ( bigger portion of right hand side part of the ship will be submerged in water ) . this caused the center of buoyancy to be located more to the right , this cause the B is very far from the G . The ship will...
  7. W

    Center of gravity vs center of buoyancy

    Homework Statement why the floating body still stable when G ( center of gravity ) is above the B ( center of buoyancy)? Homework Equations The Attempt at a Solution in my opinion , the statement is worng , because when G is above B , G has the tendency to move downward , causing the object...
  8. W

    Direction of resultant force

    isnt that the the resultant force on blade and forecs of steam of water are of same magnitude and same direction ?
  9. W

    Direction of resultant force

    the horizontal component of force should be -1.272 N + 2.54 = 1.27N N to the right, whereas the direction and magnitude of vertical force is the same ? then , the direction of resultant of force should be upwards just like the diagram below?
  10. W

    Pressure at points

    z represent the difference in height between 2 points
  11. W

    Formula of forces

    do u mean since the width is unknown and constant through out the whole object , so we can take it out and leave the ans (Fx) is Force per unit width>
  12. W

    Pressure at points

    how to relate it to the P1 ? why not P1 = P2 , which is ρg(h1 +h2 +h3) ?
  13. W

    Formula of forces

    ok , i can understand the red part of the equation (9810)(2.1)(4.2)- 9810(0.35)(0.7) -Fx = 1000(5.88)(8.4-1.401) , but 1000(5.88)(8.4-1.401) is force , am i right ? it's not force per unit width... they are not having the same unit...how cvan they be equqal to each other?
  14. W

    Direction of resultant force

    Homework Statement why the resultant force on blade is acted downwards (toward A)? why shouldn't it be slanted upwards ? since the horizontal component of the force acted 2.12kN to the left , and 0.735kN upwards , we would get the resultant force acting slanted upwards , right ? Homework...
  15. W

    Pressure at points

    it should be P/ y + z + (v^2) /.2g , where v = velocity , y = ρg
  16. W

    Pressure at points

    P +z + (v^2) /.2g , wher v = velocity
  17. W

    Formula of forces

    Homework Statement what is the 2.1 and 0.35 refers to in the equation of (9810)(2.1)(4.2)- 9810(0.35)(0.7) -Fx = 1000(5.88)(8.4-1.401) ?? is it the width ? but , the width is not given ? Homework Equations The Attempt at a Solution
  18. W

    Pressure at points

    maybe there are some points that i have left out , can you point out please?
  19. W

    Pressure at points

    can you explain how to apply the Beroulli's pronciple so that the P1 = pg(h1 +h2) ? but not P1 = pg(h1 +h2+h3) ?
  20. W

    Pressure at points

    can you explain further?
  21. W

    Pressure at points

    Homework Statement isn't that p1 and [2 at the same point ? why shouldn't the P1 = P2 , which is ρg(h1 +h2 +h3) ? Homework Equations The Attempt at a Solution
  22. W

    Coefficient of discharge

    Homework Statement why the author consider the coefficient of discharge as the z here ? what is exactly coefficient of discharge? Homework Equations The Attempt at a Solution
  23. W

    Min force to open the water gate

    Homework Statement why Fr(Lp) = FB / 2 ? can someone help to explain ? Homework Equations The Attempt at a Solution shouldn't it be 2FB = Fr(Lp) ? since FB act on 2 sides of the gate ...[/B]
  24. W

    Formula of object immersed in water

    according to 3-18 , i would get P (yc^2) A instead of P (yc) A ... am i correct ?
  25. W

    Density of body and density of liquid

    Homework Statement how can the average density of the body equal to the density of fluid(2nd photo) ? the object is not completely submerged in the liquid , so the density of object should be lower , right ? Homework Equations The Attempt at a Solution
  26. W

    Kinematic viscosity depends on pressure

    so , which is correct ? kinematic viscosity or dynamic viscosity depends on pressure?
  27. W

    Formula of object immersed in water

    Homework Statement why the y ſ P dA will equal to P yc A ? why not P (yc^2) A ? since yc = ſ y dA / A Homework Equations The Attempt at a Solution
  28. W

    Kinematic viscosity depends on pressure

    Homework Statement I was told that kinematic viscosity depends on pressure , but not dynamic viscosity Homework Equations The Attempt at a Solution in my opinion, the dynamic viscosity depends on pressure , since it's formula is μ = tau / (du/dy) , where tau is the stress . and stress can...
  29. W

    Restoring moment

    Homework Statement why the restoring moment in diagram 3-48 must be in anti-clockwise direction ? can't be in clockwise direction ? pls refer to the last photo ( i sketched it) , if the B' is located on the left of the G , teh restoring moment is clockwise, right ? Homework Equations The...
  30. W

    Weight of fluid block

    Homework Statement why the formula of weight of fluid block is given by the formula of ρg[ (R^2) - pi(R^2) ] 1? what does the 1m mean here ? shouldn't it = ρg (pi) (R^2) h ? 2. Homework Equations The Attempt at a Solution
  31. W

    Forces on submerged surface

    Homework Statement i don't understand the statement 1 and 2 , can someone help to explain ? for 1 , does the author mean Fh= Fv ?? for 2 , does the author mean Fv = Fh + W ? but in statement 1 , Fh already = Fv Homework Equations The Attempt at a Solution
  32. W

    Curvature effect can be neglected

    why ? i still can't understand
  33. W

    Prism volume

    how can The volume of the pressure prism is equal to the magnitude of the force exerted by a hydrostatic pressure P applied over an area A ?
  34. W

    Curvature effect can be neglected

    when R is big relative to l , we can only say that the two circle 'combined together' , right ? how can the curvature be neglected?
  35. W

    Curvature effect can be neglected

    what do you mean ? can you explain further?
  36. W

    Prism volume

    Homework Statement why the formula of volume is given by integral of P and dA , the integral of P and dA would yield Force , right ? Homework Equations The Attempt at a Solution
  37. W

    Support of fluid

    i am asking about , if no wall is present , how can it not eliminate stress?
  38. W

    Formula of viscosity

    i think it is wrong
  39. W

    Formula of viscosity

    i don't agree with the formula mass/ (length x area)
  40. W

    Formula of viscosity

    Homework Statement why the alternative formula of viscosity not = (mass x length ) / ( time x area) ? for force x time , we would get (mass x length ) / time ... Homework Equations The Attempt at a Solution
  41. W

    Curvature effect can be neglected

    can you explain in detail by giving analogy (is arrow represent ℓ ) ?
  42. W

    Support of fluid

    Homework Statement why the fluid need the wall to eliminate the shear stress? Homework Equations The Attempt at a Solution is it because if there is no wall to support teh fluid , the fluid would move continously , resulting the shear stress act on water?
  43. W

    Curvature effect can be neglected

    Homework Statement why when ℓ / R ≪ 1 , the curvature effect can be neglected ?? Homework Equations The Attempt at a Solution no matter how small or how big is R , it is strill considered as curvature , right ??
  44. W

    Force of bubble

    i have one more question here . I was also told that the pressure at the concave side of the bubbles is higher ... why is it so ? is it because of the circumference of the pressure at the concave side is higher?
  45. W

    Force of bubble

    Homework Statement why the force of bubble is given by the formula of 2(2 pi R ) σs ? why not (2 pi R ) σs + (2 pi R+ ΔR) σs ? Since the radius of th outer circumfernece and inner circumference are the different ? Homework Equations The Attempt at a Solution
  46. W

    Water in hose

    ok , so is my statement in post #5 correct ?
  47. W

    Force in pipe

    what do yo you mean ? we want to find the resultant force , right ? So , the correct approach would be 12cos60 + 12 , right ? since they are both directed to the right
  48. W

    Force in pipe

    so , the notes is wrong ? the velocity should add up ?
  49. W

    Force in pipe

    I want to ask A and the inlet first
  50. W

    Force in pipe

    velocity along the x direction . (circled part)
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