Recent content by Np14

  1. Np14

    What is the angular acceleration of this cylindrical system?

    Doing it symbolically makes it more confusing for me, so I will use numbers. Torque on cylinders: τ = Iα = ΣFrperp. τ = 45α = ΣF(0.5) ΣF = 90α Net force on hanging mass: ΣF = Fg - Ft = 20(9.8) - 20(a) = 196 - 20(αr) = 196 - 20(α(0.5)) Combine: 90α = 196 - 20(α(0.5)) 100α =...
  2. Np14

    What is the angular acceleration of this cylindrical system?

    Doing it symbolically makes it more confusing for me, so I will use numbers. Torque on cylinders: τ = Iα = ΣFrperp. τ = 45α = ΣF(0.5) ΣF = 90α Net force on hanging mass: ΣF = Fg - Ft = 20(9.8) - 20(a) = 196 - 20(αr) = 196 - 20(α(0.5)) Combine: 90α = 196 - 20(α(0.5)) 100α =...
  3. Np14

    What is the angular acceleration of this cylindrical system?

    I meant the mass of the two cylinders combined, which I thought constituted the entire system, but now I realize I didn't factor in the hanging weight, m1. Regardless I don't think that solving for the 90α (or the mass of the entire system) is relevant to the problem.
  4. Np14

    What is the angular acceleration of this cylindrical system?

    I did not use that equation, but I got the wrong answer, so it is most likely necessary to solve the problem. I'm pretty sure I did, however, differentiate between the two variables.
  5. Np14

    What is the angular acceleration of this cylindrical system?

    PART B ONLY: The cylinder undergoes torque when the mass m2 is removed: τNET = Iα = FNETr = 45α = FT(0.5) FT = 90α, therefore msystem = 90 kg After this step, I am not sure what to do. τ = ΣF = Fg - Ft = ma = (20 kg)(9.8 m/s2) - (90α) = 196 -...
  6. Np14

    What is the tension force for this system in rotational equilibrium?

    EDIT: EDIT: My bad, there should only be one F for the first expression (didn't use two in my calculations anyways) I see what you mean. The length should be some constant times L, I just don't know what it should be. Using the first way, sin30 x 0.6 = 0.3 I guess I just typed the...
  7. Np14

    What is the tension force for this system in rotational equilibrium?

    The system is in rotational equilibrium and therefore experiences no net torque, meaning all individual torques must add to zero. τNET = 0 = FFTsin(θ)L - FgL - Fg(L/2) τNET = 0 = FTsin30°(0.6?) - (0.5)(9.8)(0.6) - (2.0)(0.6/2) My only problem (I think) is figuring out what the length L is for...
  8. Np14

    Impulse applied to a bouncing ball

    Thank you, now it makes so much more sense. Ft = 0.5(3.7 - (-4.85)) Ft = 4.28 Ns
  9. Np14

    Impulse applied to a bouncing ball

    Ft = m(v - vo) Ft = (0.5)(3.7 -4.85) Ft = - 0.575 Ns, which is incorrect I misspoke. The ball falls due to gravity and at the instant of collision changes velocity.
  10. Np14

    Impulse applied to a bouncing ball

    I am not sure what you mean by asking what the new kinetic energy is. It would just be K = Ug, right?? 1/2mv2 = magh 1/2(0.5)(VB)2 = (0.5)(9.8)(0.7) VB = 3.7 m/s I understand your point that velocity is a vector, and the answer would be a nonzero ±2 (depends on which direction is specified as...
  11. Np14

    Rocket: conservation of momentum

    Homework Statement A fireworks rocket is moving at a speed of 45.0 m/s. The rocket suddenly breaks into two pieces of equal mass, which fly off with velocities v1 and v2. What are the magnitudes of v1 and v2? Homework Equations Conservation of Momentum m1v1 + m2v2 = m1vo1 + m2vo2 The...
  12. Np14

    Impulse applied to a bouncing ball

    Okay so I tried to find second impulse but it did not work out... KA = Ug,B + KB 1/2(0.5)(4.85)2 = (0.5)(9.8)(0.7) + 1/2(0.5)(VB)2 VB = 5.55 m/s ImpulseB = (0.5)(5.55 - 4.85) ImpulseB = 0.35 N(s) ImpulseA + ImpulseB = 2.42 + 0.35 = 2.77 N(s)
  13. Np14

    Impulse applied to a bouncing ball

    What do you mean by impulse to stop the ball? Please elaborate.
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