Ball Definition and 999 Threads

BALL (pronounced "ball") is software consisting of the versatile C++ class framework Biochemical Algorithms Library (BALL), a set of algorithms and data structures for molecular modelling and computational structural bioinformatics, a Python interface to this library, and a graphical user interface to BALL, the molecule viewer BALLView.
BALL has evolved from a commercial product into free-of-charge open-source software licensed under the GNU Lesser General Public License (LGPL). BALLView is licensed under the GNU General Public License (GPL) license.
BALL and BALLView have been ported to the operating systems Linux, macOS, Solaris, and Windows.
The molecule viewer BALLView, also developed by the BALL project team, is a C++ application of BALL using Qt, and OpenGL with the real-time ray tracer RTFact as render back-ends. For both, BALLView offers three-dimensional and stereoscopic visualizing in several different modes, and applying directly the algorithms of the BALL library via its graphical user interface.
The BALL project is developed and maintained by groups at Saarland University, Mainz University, and University of Tübingen. Both the library and the viewer are heavily used for education and research. BALL packages have been made available in the Debian project in April 2010.

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  1. L

    What technology could make a cricket ball stop and hover in mid-air?

    Just had a dream about someone that bowled a cricket ball (spin delivery) and after it bounced when it got to about a meter in height it just stopped dead in the air and hovered. What technology inside of the ball would be needed so that lift force was countered so that it would stop vertically...
  2. M

    Ball in Cone Issue: Solving for Angle X

    Guys, I have a problem I'm trying to solve for work (we're trying to inspect a hole, and I'm trying to determine its angle using a gage pin and a ball bearing). An image of the problem is attached. The known dimensions which we can measure are shown in black, and I am trying to solve for...
  3. R

    Projectiles Question -- Tiger Woods drives a golf ball on the Moon

    Homework Statement As part of a NASA experiment, golfer Tiger Woods drives a golf ball on the moon, where g = 1.60 m/s2. He ‘launches’ a golf ball with a speed of 285 km/h, at an angle of 42o with the horizontal. What horizontal distance will his drive travel before landing back on the...
  4. N

    Weighing a bowling ball project

    In bowling, the ball will have a heavy spot marked as the center of gravity (cg). This will have an additional 1oz to 5 oz of weight to compensate for when the fingers are drilled into the ball. In bowling a dodo scale is used to measure the difference in static weight of the bowling ball...
  5. Satvik Pandey

    How long the ball remains in contact with the ground when dropped

    Homework Statement A ball of mass 1kg is dropped from a height 1m . Estimate how long the ball is in contact with the ground in seconds ? Details and assumption Simplify the question by modeling the ball as an ideal spring of spring constant 100Nm . Take gravitational acceleration if...
  6. I

    Ball rolling down a ramp time difference

    suppose you had a ball rolling down a ramp, without slipping and compare it to a ball that starts with a velocity u that is horizontally to the side. how would the time taken be different to reach the bottom?
  7. O

    Experiment - beer bottle and ping pong ball

    Hello. I have a question about experiment. You know it. You need beer bottle, water and ping pong ball. You completely fill the beer bottle with water and you take the ball on the top of the bottle. The ball will not fall, if you take the beer bottle upside down. OK, the atmospheric force...
  8. P

    Frequency of oscillation of a ball?

    Homework Statement Hi, For one of my physics projects i need the natural frequency, or frequency of oscillation of a ball. I don't even know where to start. I've got a short article of an experiment similar to mine where they also use this natural frequency. So if my story is unclear, which...
  9. A

    How far beyond the fence does the ball strike the ground?

    Homework Statement A baseball is hit at ground level. The ball reaches its maximum height above ground level 3.1 s after being hit. Then 2.6 s after reaching its maximum height, the ball barely clears a fence that is 97.2 m from where it was hit. Assume the ground is level. a) How far...
  10. putongren

    Equations for cannon ball on a planet

    I've been trying to develop a equation for a ball that is shot out of a cannon and see if it would return to the surface of a circular planet. This is not a homework. It's something that I have been thinking about for a long time. Can somewhat help out to derive such a formula?
  11. B

    How Does Normal Force Change on an Inclined Plane?

    Help me to understand my physics homework Suppose if a ball is rolling down in an inclined plane, what happens to the normal force acting on it? How to understand the Normal force in this situation Please explain Thanks
  12. Adjoint

    Acceleration at the time of throwing a ball

    Homework Statement (It's just a simple question.) A ball is thrown straight up in the air so that it rises to a maximum height much greater than the thrower's height. Is the magnitude of the acceleration greater while it is being thrown or after it is thrown? Homework Equations 1D...
  13. P

    Ball collision momentum problem

    Homework Statement Hello. I was solving this problem about two balls in a plane colliding elastically. The first one had mass 100g radius 5cm and started with velocity of 3m/s to the right and hit the second ball with mass 50g radius 3cm(initially stationary). It hit the second ball such...
  14. T

    Why do we need the vertical distance that a bouncing ball traveled?

    1. Homework Statement 1.Main question: Why would anyone need to know the total VERTICAL distance traveled by a bouncing ball? 2.Other question: Does anyone have a link to an explanation (or could explain themselves) on how to calculate the total HORIZONTAL distance traveled by a bouncing...
  15. T

    How to calculate the horizontal distance traveled by a bouncing ball?

    Does anyone have a link to an explanation (or could explain themselves) on how to calculate the total HORIZONTAL distance traveled by a bouncing ball? I have filmed and analysed (plotted the points) of a few trajectories, so I have the values, I just need to explain why i got those values and...
  16. N

    Energy During Motion and Bounce of a Ball

    Here are the questions: If a ball is thrown upwards with a initial velocity (u) from the hand, the ball throws to the highest point and after bouncing the floor, it bounces back to its initial position. In this case, it is said that air resistance is not negligible. Okay, I am confused by...
  17. N

    New Soccer Ball: Why 2 (or 3) Plates?

    So I saw how the new soccer balls are made with 2 (or was it 3) plates that are a odd shame instead of the traditional load if hexagons and I was wondering why this makes the ball better
  18. T

    Does a ball always bounce the same fraction of the previous height?

    Homework Statement I need to know whether a ping pong ball bounces the same fraction of the previous height or does the fraction change? For ex. if I drop the ball from 1m and it bounces back to 0.7m, it decreased by 30%, will it always decrease by 30%, or will the percentage change...
  19. P

    Steel ball bearing in a magnetic field

    I seem to be unable to confirm to myself what's really going here. Basically, we have a rectangular shaped magnet with north and south at opposite ends. A steel ball bearing is placed to the left of the magnet where it is equidistant from the north and south ends. Consequently, a force...
  20. T

    Find the height of a bouncing ball at any given time

    Homework Statement Find an analytical model for the height of a bouncing ball to be able to find the the height of the ball at any given time. In other words, as I understand, write an equation that would define the trajectory of a bouncing ball. Let's say the coefficient of restitution (COR)...
  21. N

    Sliding time before a ball begins to roll on a horizontal surface

    Homework Statement A ball is released along a horizontal surface with a co-efficient of friction Us at a speed V. Find the time it takes for the ball to start rolling (leave the moment of inertia as I). Homework Equations Quite a few, all of them are stated in my working (that I...
  22. X

    An empty ball in arbitrary metric space

    Is it possible for a ball(with nonzero radius) to be empty in an arbitrary metric space?
  23. H

    Archived Rotational Motion -- a hollow ball rolls down a ramp

    Homework Statement Starting from rest, ahollow ball rolls down a ramp inclined at angle θ to the horizontal. Find an expression for its speed after it's gone a distance d along the incline. Homework Equations I for sphere = 2/5*M*R^2 The Attempt at a Solution I know we have to use...
  24. A

    Kinematics Problem Ball throwing

    Hi, Could you please look at this problem in the picture and my steps? (check my answer) I do not have the solutions to the problem weirdly.
  25. R

    How High Does the Apple Reach When Thrown at 55 Degrees?

    Homework Statement You want to throw an apple to your buddy on the second floor balcony that is 2.2m above where you release the apple. When you throw the apple with a speed of 14m/s at an angle of 55° above the horizontal, it gets to your buddy who catches it on the way down. Find the maximum...
  26. D

    Solenoid to fire magnetic ball, question about best core material)

    So I want to fire a magnetic ball through a solenoid coil but want to know if core material can enhance the performance. Would wire wrapped around soft Iron tube core work better then say a thin copper tube? The aim is to increase efficiency so less power needs to be used to fire the magnetic...
  27. T

    What are the Kinematics of a Ball in Projectile Motion?

    Homework Statement In a friendly game of handball, you hit the ball essentially at ground level and send it toward a wall 4.6 m away. The ball is hit with a speed of 20 m/s at 40 degrees above the horizontal. a.) At what height does the ball strike the wall? b.) Calculate the speed of...
  28. D

    Ball Drop and Projectile Motion: When Will They Meet?

    A ball is dropped from a 100m cliff. at the same time another ball is thrown up such that it has enough velocity to reach the top. at what distance from top of the cliff will the two balls meet?
  29. N

    What Happens When a Hot Steel Ball is Dropped into Water or Ice?

    Homework Statement If a steel ball of mass 100g and 100°c is dropped into 1litre of water at 20°c, what is the temperature rise? What would happen if it were dropped into a mixture of ice and water at 0°c?Homework Equations Q=mcΔT Q=mlm where ml is latent heat of melting Q lost = Q gained The...
  30. J

    Which forces affect the ball in A, B, C and D?

    Homework Statement I have attached a picture. I just want to know which forces affect the ball at different times: A, B, C and D. Could someone please sum it up really fast? : -) Homework Equations The Attempt at a Solution
  31. L

    Which would be faster: A ball rolling down a ramp with no groove

    Homework Statement Which would be faster: A ball rolling down a ramp with no groove, or a ball rolling down a ramp with a groove? What effect does the radius have, if any? Disregarding resistance and whether or not the ball rolls in a straight line. Homework Equations The Attempt at a...
  32. P

    Throwing a ball against a wall for projectile motion

    Homework Statement A woman throws a ball at a vertical wall d = 3.4 m away. The ball is h = 1.7 m above ground when it leaves the woman's hand with an initial velocity of 11 m/s at 45°. When the ball hits the wall, the horizontal component of its velocity is reversed; the vertical component...
  33. U

    Elastic collision between ball and block

    Homework Statement A block with large mass M slides with speed V0 on a frictionless table towards a wall. It collides elastically with a ball with small mass m, which is initially at rest at a distance L from the wall. The ball slides towards the wall, bounces elastically, and then proceeds to...
  34. E

    Solving Projectile Motion: Ball Thrown from Building

    Homework Statement This is a review question from the test I did few months back, and I need to review it for my finals. A ball is thrown from the top of a building 35m high with an initial speed of Vi at an angle 30° above the horizontal. The ball strikes the ground at a point 80m from...
  35. M

    Conservation laws - Ball hitting a rod about its end

    Homework Statement Homework Equations v = wr K_total = 1/2Mv^2 + 1/2Iw^2 L = Iw p = mv The Attempt at a Solution a. No friction or other outside forces are acting on the system, so linear momentum is conserved. The collision is elastic, so kinetic energy is conserved. There...
  36. A

    Height of ball bounce with air resistance

    Homework Statement Ball with mass of 0.7 kg and radius 0.15 m is dropped from top of the building 30 m tall. Force of air resistance which acts on ball is given with the equation: F_r = \frac{1}{2} c S ρ v^2 where c = 0.5 S = r^2 ∏ ρ = 1.29 \frac{kg}{m^3} v = current speed. How tall will...
  37. T

    Which Plasma Ball Will Produce Light, Plasma, and Spark?

    if we have 3  plasma ball.and they have the same pressure gas ...one have low current power .the scond have  middle current power .the third have strong current power .. ...so which will of them produce ...light ..plasma ...spark..
  38. S

    Energy changes of a ball thrown up

    Homework Statement A hollow ball has a mass of 0.310 kg and radius 0.0340 m. The ball is thrown vertically upwards from rest. It rises through a height of 1.40 m then drops down again. When it is released, it is moving upwards at 5.24 m s−1 and rotating at 2.70 revolutions per second. For...
  39. M

    Topspin for a tennis ball to not change velocity while bouncing

    Homework Statement Homework Equations Tangential v = wr The Attempt at a Solution I first drew a force diagram for when the ball contacts the floor. Topspin means the ball is moving tangentially backward. Therefore, the bottom moves at v - wR. Friction works opposite in the...
  40. D

    Saltwater Elevation below Ball: 1.85cm

    Homework Statement A plastic ball of 1cm diameter and 10^-8 Coulomb of charge is suspended by an insulating string. The lowest point of the ball is 1cm above a big container of saltwater. Indeed, the water's surface rises a bit. What is the water elevation height exactly below the ball? Ignore...
  41. M

    Ball rotates around a shaft by two cords

    1. Homework Statement A 1.0kg ball is attached to a vertical rod by two strings. Each string is 1.0m long, and they are attached to the rod a distance of 1.0m apart. The rod-ball-strings setup is rotating about the axis of the rod. As it rotates the strings are taut and form an equilateral...
  42. R

    Collision - a ball and string form a pendulum

    Collision -- a ball and string form a pendulum... 1. A 1.0-kg ball is attached to the end of a 2.5-m string to form a pendulum. This pendulum is released from rest with the string horizontal. At the lowest point in its swing when it is moving horizontally, the ball collides elastically with a...
  43. A

    Open Ball in Metric Space (R2, d1)

    Homework Statement What is the set of the unit ball centered at 0 = (0,0) in the (x1, y2)-plane, where d1(x,y)=|x1-y1|+|y1-y2| is in the metric space (R2, d1) Homework Equations An open ball is Br(x)={y\inX|d(x,y)<r} The Attempt at a Solution I know the solution is this...
  44. D

    MHB How High Can a 100lb Ball Be Thrown Upwards at 100ft/sec?

    What is the max altitude when a ball of 100lb is throwing vertically upward with a v = 100 ft/sec? g = -32ft/sec per sec I can't figure out how to incorporate the weight. \[ h(y) = y_0 + v_0t + a\frac{t}{2} = 100t - 16t^2 \] but can this equation be used? It isn't considering the weight of...
  45. W

    How Does Depth Affect the Buoyant Force on a Submerged Beach Ball?

    A beach ball is made of thin plastic. It has been inflated with air, but the plastic is not stretched. By swimming with fins on, you manage to take the ball from the surface of a pool to the bottom. Once the ball is completely submerged, what happens to the buoyant force exerted on the beach...
  46. Y

    Projectile Motion Ball Hurl Question

    Homework Statement If you can hurl a ball so that its initial speed is 30m/s, what is the widest river you can throw it across? Homework Equations The range equations, t=2(vi)(sintheta)/g d=visin2theta/g The Attempt at a Solution I know you have to use components so what I...
  47. B

    Ball rolling down slope (with wedge-shaped groove)

    1. Homework Statement [/b] The question is B7 here: http://www-teach.phy.cam.ac.uk/dms/dms_getFile.php?node=7787 I managed to derive the acceleration required in the first part, but the second part is giving me trouble. Homework EquationsThe Attempt at a Solution I have calculated the moment...
  48. K

    Closed ball is manifold with boundary

    I've been trying to prove that the closed unit ball is a manifold with boudnary, using the stereographic projection but I cannot seem to be able to get any progress. Can anyone give me a hint on how to prove it? Thanks in advance :)
  49. M

    Ball bouncing on inclined ramps

    Homework Statement Last week we did a practical in which we bounced a ball from the same point onto an inclined ramp, from 10-50 degrees and measured the distance from where the ball was dropped and when it hit the table (i.e. place where it landed after it bounced off the ramp). Homework...
  50. B

    Analysis of Billiards Ball Motion Following a Horizontal Queue Impact

    [b]1. Encountered with cue to a massive billiards ball, which is initially at rest, see figure uploaded. The ball has radius R and mass M. The queue hits with force F horizontally into the bale height h above the table, and the shock lasts a very short time Δt. It is reported that the moment of...
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