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  1. H

    Superposition and Interference problem

    Can someone help me please?? I've got my exam tomorrow morning!
  2. H

    Superposition and Interference problem

    You're referring to the frequency equation: f= mv/2L. I tried using that but the answer comes out to 8.33 m, whereas at the back of the textbook, it is 18 cm :S. This is my working: frequency for the 8 cm one where m=3 as there are 3 antinodes: f= (3 v) / (2*0.08) frequency for unknown...
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    Superposition and Interference problem

    I have two questions from the Superposition unit that I don't get it. I'd really any help on these as I have my physics exam on monday! Thanks for any help! Homework Statement A steel wire is used to stretch a spring. An oscillating magnetic field drives the steel wire back and forth. A...
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    Elastic Collision of a gold nucleus

    My formula sheet has a weird way of writing the formula and they had m2 on there, thats why instead of having 2 in my numerator, i have 100. You guys saved me from using that formula on the exam! Thanks a lot! [Now my logical answer matches the math too! Yay!]
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    Elastic Collision of a gold nucleus

    hehe. i do get that. the only discrepency is that the formulas give a greater velocity for the gold nucleus. Therefore, making it have a higher KE. Or should I not use the formula over here and it's not a REAL elastic collision.
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    Elastic Collision of a gold nucleus

    This question is from a past midterm and the answer given in the answer key is D. I've thought of it in terms of momentum and since velocity is squared in the KE expression, larger velocity of the alpha particle gives it a greater KE. Besides this, I don't know what to conclude from this...
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    Elastic Collision of a gold nucleus

    Homework Statement A positively charged alpha particle is fired, in a direct line, at a positively charged gold nucleus: o--> O o: alpha, O: golden nucleus. Because of their mutual repulsion, the alpha particle does not actually hit the nuleus: it comes to rest, for a...
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    Kinematics of jet-ski - how far does Sam land?

    I got the answer now! Yay! Thank you so much for guiding me! I love this forum! I'm feeling more confident now and learning more things by second :D.
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    Kinematics of jet-ski - how far does Sam land?

    Thanks a lot! That solves the mystery. I assumed that the force of thrust was only present while on the ramp. So now, I have an acceleration in both x and y directions and I can use a similar method to solve for the horizontal distance.
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    Kinematics of jet-ski - how far does Sam land?

    For the acceleration, you mean? The overall answer for some reason isn't turning out to be correct. I checked my calculations many times. In the beginning, I made a few error but then I corrected those, but the answer I'm supposed to be getting is 110 m, not 84.4 m :(. I hate textbook questions...
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    Net Work

    I was thinking of the work-kinetic energy theorem were Wnet= delta K. But maybe I should always stick to the equation: Ki + Ugi + Wext= Kf + Ugf + Delta E (thermal), and plug in things to see where the conversion is occuring. My textbook gives too many formulas which creates a lot of confusion!
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    Net Work

    Sorry :$. It's just that I'm not really good with the concept of work. I read the textbook and did all the recommended questions but this was from a practice midterm. I'll try not to post as much now and try to think them through. But I only post questions if I try them at least 3-4 times and...
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    Energy Conservation.

    Nice!! Thank you so much!!!!
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    Kinematics of jet-ski - how far does Sam land?

    I'm getting the same answer: ma= 200 - mg (sine theta) 75a= 200 - (75)(9.81) (sin 10 degrees) a= 0.96318 m/s^2.
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    Net Work

    Homework Statement A mass of 500 g is attached to the bottom of an unstretched spring attached to the ceiling, and has a spring constant 10 N/m. The mass is then released. What is the net work done on the mass between the point where it was released and the lowest point that it reaches...
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    Kinematics of jet-ski - how far does Sam land?

    That was a typo. Sorry. Sam's mass is actually 75 kg.
  17. H

    Energy Conservation.

    by writinf 4 + x, i get 2.2 m, which is still not the correct answer. Also, for Ke +PE + spring=0, why is the sum 0?
  18. H

    Sprinter Work and Power

    Thanks a lot! I understand it now =).
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    Sprinter Work and Power

    I didn't know that there was a difference between the two. So whenever I have a velocity I should use the second one?
  20. H

    Energy Conservation.

    Homework Statement A 10 kg vox slides 4.0 m down the frictionless ramp shown in the following link. It then collides with the spring whose spring constant is 250 N/m. a. What is the maximum compression of the spring? b. At what compression of the spring does the box have its maximum...
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    Kinematics of jet-ski - how far does Sam land?

    Homework Statement Sam (5) kg takes off up a 50-m high, 10 degree frictionless slope on his jet-powered skis. The skis have a thrust of 200 N. He keeps his skis titled at 10 degrees after becoming airborne, as shown in the Figure. How far does Sam land from the base of the cliff? I drew...
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    What is the glider's velocity just after the skydiver lets go?

    Thanks a lot alphysicist! I love how you take words right out of my textbook and relate them to these problems. It makes so much more sense to me now =). I feel so guilty though for posting so many questions..it's just that I have my physics exam next Monday and I want to prepare as much as...
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    What is Bob's maximum power output as he throws the rock?

    Thanks a lot tiny-tim and PhantomJay! The help is much appreciated!
  24. H

    What is the glider's velocity just after the skydiver lets go?

    There is no impulsive force, so velocities don't necessarily change. right? :D
  25. H

    What is Bob's maximum power output as he throws the rock?

    But I don't know work. I still don't get it :(.
  26. H

    What is Bob's maximum power output as he throws the rock?

    We apparently covered this method but the only work-energy equation that I know is: Ki+ Ui + Wext= Kf+ Uf+ delta E (thermal). Can you please guide me on how to set it up the work-energy way because I've seen other questions in the textbooks like that but I do them different.Thanks for your help =).
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    Bouncing Ball Position, Velocity and Acceleration Graphs.

    Thank you so much! That makes a lot of sense to me now =).
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