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  1. M

    Electric Field Problem in a Tube

    It is. I just make stupid mistakes. Thanks! Do you see anything else wrong with the calculations? I think I calculated it with the right number I just typed it into here wrong.
  2. M

    Electric Field Problem in a Tube

    Homework Statement An alpha particle (a helium nucleus) is traveling along the positive x-axis at 1425 m/s when it enters a cylindrical tube of radius 0.700 m centered on the x-axis. Inside the tube is a uniform electric field of 5.00x10-4 N/C pointing in the negative y-direction. How far does...
  3. M

    Rotational Motion/Pulley Problem

    Is it true that a1+a2+r(alpha)2=0 or pretty much that a1 + 2a2 = 0?
  4. M

    Rotational Motion/Pulley Problem

    Okay I think I still might be lost, but I'm thinking that the tension force on disk 2 will produce a torque that has the same direction as the angular acceleration, so even if it were negative they would both cancel out to give Tr=I(alpha). I dont really know where I am going with this, because...
  5. M

    Rotational Motion/Pulley Problem

    I have no idea. I guess I'm not sure if the equations are the same because I don't know if they are both accelerating downwards. How do I know? Also when I calculated the torque, did I use the right equation or should it have been negative? Thanks for your help!
  6. M

    Finding distance that a pad is compressed after being dropped

    haha sorry the second equals was supposed to be a plus. my bad. Yea solving for x would have been interesting.
  7. M

    Heat/First Law of Thermodynamics/Calorimetry - Have work done

    I would start with the idea that the -q(water)= q(ice) This is because the water is warmer and it is losing heat to the ice. It will continue transferring heat until both are at the same temperature. Since the calorimeter has negligible heat capacity, it does not absorb any of the heat that the...
  8. M

    Torque direction using right hand rule

    I think that would be correct if you were saying that the counterclockwise direction is positive. That would make T2 negative, if that makes sense.
  9. M

    Finding distance that a pad is compressed after being dropped

    I think you probably have to do something with the impulse that the pad delivers to the egg: The egg hits the pad with some initial velocity and then is brought to a complete stop before most likely bouncing up a little bit. This is essentially an acceleration in the upward direction. Then...
  10. M

    Conservation of energy

    The normal force is not equal to the force of gravity because there is another force acting in the vertical direction---the force being applied to the sled at the 30 degree angle.
  11. M

    Rotational Motion/Pulley Problem

    Homework Statement Two uniform disks with the same mass are connected by a light inextensible string supported by a massless pulley, on a frictionless axis. The string is attached to a point on the circumference of disk A. The string is wound around disk B so that the disk will rotate like a...
  12. M

    Conservation of energy

    Amusing problem by the way. I think that you did it right, I got that it was 0.5482 L or 0.008842 kegs of beer.
  13. M

    Angular Speed

    Thank you for your help so far by the way! I set up an equation for the rotation, but I'm still a little confused on the rotation. I(alpha)=F(friction)r (1/2mr^2)a/R=F(frict)r ma/2=F(frict) F(frict)= I guess I really don't know how to relate them? I was also thinking that...
  14. M

    Tension connecting the cable between the passenger and the engine

    i would try setting up free body diagrams for all of the parts of the train. Then you can set up equations for the sum of the x and y force components for each train part and can combine them to solve for the 2 tensions.
  15. M

    Rolling Without Slipping/Loop Problem

    ok thanks for all of your help!!!!
  16. M

    Rolling Without Slipping/Loop Problem

    Yea I got 7.15 which is 27/10R, but I got it wrong on my online hw. Isn't it true that the force of normal reaction at the top of the loop is zero if it is just going fast enough to make it over. If so, wouldn't mg=mv^2/R.
  17. M

    Rotation Problem/Total Kinetic Energy

    Homework Statement A spool of mass 8.67kg and radius 4.58m is unwound by a constant force 48.1N pulling on the massless rope wrapped around it. Assume the moment of inertia of the spool about O is 3/4mr^2 and it rolls w/o slipping. When the center of the spool has moved a distance d, find the...
  18. M

    Rolling Without Slipping/Loop Problem

    can i still solve for the velocity at the top in the same way? If not, how would I incorporate rotational velocity into that?
  19. M

    Rolling Without Slipping/Loop Problem

    Homework Statement A small, solid sphere of mass 0.6kg and radius 27 cm rolls without slipping along the track consisting of slope (at an angle of 60degrees from horizontal) and loop-the-loop with radius 2.65m at the end of the slope. It starts from rest near the top of the track at a height...
  20. M

    Angular Speed

    So do I use those equations....or is it a lot easier than I am thinking? I was thinking you could do something with work being equal to final ke - initial ke and also that torque x change in time= change in angular momentum. I guess I am still really lost.
  21. M

    Angular Speed

    Homework Statement A uniform disk is set into rotation with an initial angular speed about its axis through its center. While still rotating at this speed, the disk is placed in contact with a horizontal surface and released. What is the angular speed of the disk once pure rolling takes place...
  22. M

    Angular Momentum Problem

    Thanks a lot! yea that makes sense. so i guess you can kind of think of it as the moment of inertia of a hollow cylinder?
  23. M

    Angular Momentum Problem

    Homework Statement The problem asks to calculate the angular momentum for a metallic bob that is suspended from the ceiling by a thread of negligible mass. The angle between the thread and the vertical is 30degrees. It is also given that the mass of the bob is 7 kg and the length of the thread...
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