Recent content by OlderDan

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    Explaining Angular Frequency: \theta, m, R, r & k

    From the diagram in the link you posted you should be able to write an expression for the elongation (or compression) of the spring Δx in terms of the small angular displacement of the wheel from the equilibrium position. The force applied at the point of connection between the spring and the...
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    Electron Accleration Calculation | Homework Solutions

    Look here https://www.physicsforums.com/showthread.php?t=110015 to find the 1-D kinematics equation that relates the change in velocity to a known acceleration over a known distance.
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    Understanding the Process: Jump Starting a Car Battery in Series or Parallel"

    A "flat" battery is more complicated than a resistor. The simplest way to model a dying battery is as a constant source of emf with an increasing internal resistance. A voltmeter with huge internal resistance draws essentially no current, so if the voltage is measured with no other load on the...
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    Rotational Mechanics (Conveyor belt)

    The angular velocity is not constant. The instantaneous power is changing during the acceleration phase. You cannot use torque times final velocity to find the average power. The average power is the total work done on the wheel divided by the time interval it takes to do the work. The work...
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    Calculating Linear Momentum of a System with a Bullet and a Rod Collision

    Your initial idea for finding the angular velocity of the system after the collision is correct. Once you have found ω you have two ways to approach the solution. You can either find the center of mass of the whole system and use the distance from the pivot to the CM with ω to find the...
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    Calculating Linear Momentum of a System with a Bullet and a Rod Collision

    You calculated the velocity of the end of the rod. The only thing moving with that velocity is the tiny bit of mass at that end. Everything else is moving slower. The linear momentum of a system of particles is the sum of the linear momenta of each bit of mass in the system. The concept of...
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    Velocity and Acceleration homework

    Think about the highlighted text. What function of the form v = f(t) is going to give you v0=0.6m/s?
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    Calculating Linear Momentum of a System with a Bullet and a Rod Collision

    The velocity you calculated is not the velocity you need. Your equation for P should give you a hint about the velocity you do need.
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    Standing Waves on a String (Melde's Experiment)

    All the information you need is given. You need to find the relative change in the wavelength to determine the relative change in velocity, and from that determine the relative change in tension, and ultimately the relative change in the mass.
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    Why Does Changing Magnetic Field Direction Affect Current in a Wire Loop?

    Looks like you have not computed the change in field correctly.
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    Rocket accelerating thru a dust cloud

    This does not look right dV = adt - V_0 = V_1 - V_0 \cr The definition of acceleration is just a = dV/dt Since the mass of the rocket is not changing, you can treat the collision//expulsion of a mass dm using conservation of momentum. It does not matter that the gas expelled...
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    How Does Tension Affect a Bicycle on an Incline?

    The key point here is that the force of the rope acting on the bike is NOT contributing to the force needed to keep the bike from moving down the plane. There are equal and opposite forces acting on the bike at the ends of the rope between the wheel and the frame. This is no different from...
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    Hoop Rolling Up Ramp: Confirm if Altitude Higher Than in Part A?

    I assume your part f) is actually asking you to compare the altitude to that attained in part e), since part a) has nothing to do with altitude, but the problem is poorly stated since it does not tell you what to assume about friction. The answer depends on what you assume about the coefficient...
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    How to get the constraint equation of this problem

    https://www.physicsforums.com/showthread.php?t=138432&highlight=holonomic
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    How Does Cutting a Spring in Half Affect Its Oscillation Period?

    Here is a hint then: How far does the middle of the spring move when the end originally attached to the mass moves a distance x?