Recent content by JustinLiang

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    Consequences of an Oversized Pulley Bore Hole in Conveyor Systems

    What would happen if the bore hole of a pulley in a conveyor was significantly larger than the shaft like in the figure below: I would imagine if the RPM was high, the whole system would shake violently. However, what if the RPM was around 30 RPM. Would the conveyor still function properly...
  2. J

    Calculating the horsepower for a motor

    So I would need a gearbox that can get me to 17.5 RPM right? When choosing this gearbox wouldn't my torque values change as well so that would affect the horsepower value? Finally, doesn't it take time to wind up so it won't be 17.5 RPM right at the start? The rod in total weighs 250 lbs.
  3. J

    Calculating the horsepower for a motor

    Homework Statement This is not really a homework question, it is a question for a project I am working on. So I have a heavy rod that is 1.4 m long and I want to get a motor to rotate it (I would like to see if this is even plausible). I calculated the moment of inertia for this rod to be 75.2...
  4. J

    Leveling mounts for a platform to hold around 300 lbs?

    So the 2 1/2" thread length means that you can adjust the table up to 2 1/2"? Or would it be less since some of the thread length is inside the mount. Also, what material do you guys recommend I use for the actual platform itself?
  5. J

    Leveling mounts for a platform to hold around 300 lbs?

    I need to build a platform (10 in off the ground) that can hold a fan, air damper and silencer which is in total around 300 lbs of weight. I was looking at these leveling mounts that I could use for the table feet: I noticed that there is one that says 300 lbs capacity per mount and...
  6. J

    Finding the differential equation for a oscillating system

    Homework Statement The Attempt at a Solution I don't think this is the correct answer because for some reason I have a constant mg term. Usually I get mgsinθ and from small angle approximations it becomes mgθ, but this time I am getting mgcosθ and from small angle approximations it...
  7. J

    Separable equations: How do you know which variable to solve for?

    Separable equations: How do you know which variable to solve for? + extra question Homework Statement I attached a sample problem with variables u and t. How do I know what the answer should be at the end? In terms of u or in terms of t or it doesn't matter? Homework Statement I also...
  8. J

    Dependent motion with ropes question

    Homework Statement I attached the problem with my attempt. I think the geometry I used is correct but I am getting the wrong answer. When I take the flip Va/V (as shown in my attempt) I get the right answer. I am not even sure if I can relate velocity with a triangle. The method I used...
  9. J

    Finding wavelength and wave speed in a sinusoidal wave.

    Oh I see because we start at x=0. Thanks for the help!
  10. J

    Finding wavelength and wave speed in a sinusoidal wave.

    Could you please explain to me how you got 0.15s for the -x direction? Isn't the time interval the same? But yeah I think he is correct, it took 0.025s to travel from 0m to 0.09m, so the velocity is about 3.6m/s and wavelength is 0.144m.
  11. J

    Finding wavelength and wave speed in a sinusoidal wave.

    Homework Statement A sinusoidal wave is propagating along a stretched string that lies along the x-axis. The displacement of the string as a function of time is graphed in the figure (attachment) for particles at x=0m and x=0.0900m. (A) What is the amplitude of the wave? 4mm (B) What is the...
  12. J

    Conservation of momentum/mass when dropping an object on a spring.

    I just tried a different calculation: If all the energy is conserved then: PE=KE(with both masses) 8.624J=(2.4kg)(v^2)/2 v=2.68m/s This answer tells us all the PE becomes KE in the combined mass. However the answer key has a v=2.6m/s so I don't think this is right. Maybe the answer key is...
  13. J

    Conservation of momentum/mass when dropping an object on a spring.

    Yeah it is totally inelastic so all the energy would be conserved. But how do you explain the differences in the energy before collision 8.624J and after collision 7.905J (I initially typed out the wrong values).
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    Conservation of momentum/mass when dropping an object on a spring.

    If that's the case shouldn't 7J get me the correct amplitude? The answer suggests I use 8.6J, but this energy is not conserved?
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