Recent content by Rain10399

  1. Rain10399

    Finding the pressure of a gas in three identical balloons

    Yes, now I managed to solve the problem! Thank you so much to everyone who responded ^^. I love this forum.
  2. Rain10399

    Finding the pressure of a gas in three identical balloons

    Ohhh. In the book it said balloons so I thought they actually were balloons. Thank you! So because there's no heat exchanged and no work done the internal energy remains the same? I think I understand this part now:D Then U1=UA+UB and (nA+nB)CvT1=nACvTA+nBCvTB, like Chestermiller said Thank...
  3. Rain10399

    Finding the pressure of a gas in three identical balloons

    nA=PAV/RTA nB=PBV/RTB nC=PCV/RTC first law energy balance: U1=-W1 But I wasn't sure what formula to use for W here, so I searched on the internet for one. nACvT1 + nBCvT1=-K[(2V)1-γ-(V)1-γ]/1-γ I will assume that the balloons are filled with helium, which is a monatomic gas, so: (γ = 1.66)...
  4. Rain10399

    Finding the pressure of a gas in three identical balloons

    It means that the energy is transferred to the surroundings only as work, and the system doesn't transfer Q with its surroundings. U = nCvT and U = -W (because Q=0). U1=(nA+nB)CvT= nACvT + nBCvT= UA + UB
  5. Rain10399

    Finding the pressure of a gas in three identical balloons

    Homework Statement An adiabatic isolated system is formed of three identical balloons (of unknown volume). The balloons are joined by tubes of negligible volume. Each tube has a faucet/tap that is initially closed. The balloons have different quantities of the same ideal gas. After opening...
  6. Rain10399

    Finding the speed's dependence on angle θ

    Oh, yes, you're right. Thank you for helping me with this problem!
  7. Rain10399

    Finding the speed's dependence on angle θ

    So can h be the difference between A and D (or E. D and E are supposed to be at the same height, but I'm not sure if that can be seen on the drawing)? Then h = sin α * AE and AE = cos θ * l. So mg * sin α * cos θ * l = mv2/2, and from there I can express v in terms of θ. However, I had to make...
  8. Rain10399

    Finding the speed's dependence on angle θ

    Oh! Then what is the relevant height? At the start there's no kinetic energy, only potential energy, so I still need to express the h in mgh.
  9. Rain10399

    Finding the speed's dependence on angle θ

    The relevant height is from the base of the plane to the position of A or to m's initial position (which have the same height)
  10. Rain10399

    Finding the speed's dependence on angle θ

    I'm trying to find the height at which is m in terms of angle θ, so that I can replace h with the angle in formula mgh = mv2/2. I don't know how else to solve the problem.
  11. Rain10399

    Finding the speed's dependence on angle θ

    So I found h = sin α * AC, and now I'm trying to find AC in terms of angle θ.
  12. Rain10399

    Finding the speed's dependence on angle θ

    I laid down the coordinate system on the surface of the plan at the origin A, but I didn't manage to express the first position of m in terms of the angle θ. I drew a straight line between the first position of m and B, but the triangle with the angle θ in it is not right, so I'm not sure how to...
  13. Rain10399

    Finding the speed's dependence on angle θ

    Homework Statement Find v(θ), the dependence of the speed of the object on the angle θ. The string is ideal and there's no friction. Homework Equations - The Attempt at a Solution I'm quite sure I should use the conservation of energy mgh = mv2/2, but I don't know how to express h with the...