Recent content by ankurb

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    Conservation of Energy ski jump problem

    Your value of Vf is incorrect, probably because you left the term 'm' in your equation. Also, 'gh' shouldn't be there in the RHS, because the diagram clearly shows them at the same level. Using mgh = 1/2 m v^2 (because initially, it has only potential energy, before going off ramp, only...
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    Solving a Difficult Force Problem with Multiple Unknowns

    Solved I agree, taking the derivative is easier. dm / d(theta), when equated to zero, gives tan(theta) = \mu, so \mu = atan .35, giving \theta = 19.3 degrees. Substituting in the expression for mass, the value of the highest mass that can be pulled comes out to be 340 kg.
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    Force exerted on motorcycle and rider

    Solved Oh. Right! I thought we were only supposed to consider the vertical force due to normal reaction. If I factor in the force exerted by the motorcycle to go up the incline, then I get the answer. -mg sin theta + F = ma or, F = m(g sin theta + a) = 60 x (9.8 sin 10 deg + 3) = 282 N...
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    Distance between tennis ball and the top of the net

    You need to substitute -g for acceleration, since the 'direction' of g is downwards.
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    Force exerted on motorcycle and rider

    Homework Statement A motorcycle and 60.0 kg rider accelerate at 3.0 m/s^2 up a ramp inclined 10 degrees above the horizontal. (a) What is the magnitude of the net force acting on the rider? (b) What is the magnitude of the force on the rider from the motorcycle? Homework Equations Net...
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    How High Are Mesospheric Clouds That Appear 38 Minutes After Sunset?

    The question also gave a hint - to look at the solution for the session opener question of the chapter; which is basically about calculating the Earth's radius the way you mentioned, i.e., measuring the time difference in sunsets if a person stands up. So, I read your stuff, sat down to make a...
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    How High Are Mesospheric Clouds That Appear 38 Minutes After Sunset?

    There WAS one more paragraph, in between the two I wrote here, but I omitted that because of no significance - it was simply a history of prominent mesospheric cloud appearances. You know, R&H does give a lot of extra tidbits of information (I like that, BTW).
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    How High Are Mesospheric Clouds That Appear 38 Minutes After Sunset?

    Homework Statement Homework Equations theta = length / radius The Attempt at a Solution I came across this question in Fundamentals of Physics (Resnick / Halliday / Walker), in the chapter Measurement. Now I understand that this is a simple geometry-based question. Basically, the '38...