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. P

    GeForce Impact: Tennis Ball Hits Head

    I have a question concerning GeForces. imagine a tennis ball that weighs 57 Gramm Hits a human head that weighs 4 Kilogramm on the forehead, at a speed of 120 kilometers per hour. the head moves back 15 centimeters until it stops because of the resistance of the spine. how much g-force did the...
  2. Eclair_de_XII

    How to find the acceleration of a rebounded ball?

    Homework Statement "To test the quality of a tennis ball, you drop it onto the floor from a height of 4.00 m. It rebounds to a height of 2.00 m. If the ball is in contact with the floor for 12.0 ms, (a) what is the magnitude of its average acceleration during that contact and (b) is the average...
  3. Eclair_de_XII

    How to find the acceleration of a ball rolling on ground?

    Homework Statement "A ball of moist clay falls 15.0 m to the ground. It is in contact with the ground for 20.0 ms before stopping. (a) What is the magnitude of the average acceleration of the ball during the time it is in contact with the ground? (Treat the ball as a particle.) (b) Is the...
  4. F

    Ball bounce angle on inclined surface

    Homework Statement Ball strikes inclined plane of infinite mass with velocity v vertically. Elastic collisions. Velocity and direction after collision? One way of solving is take components along and perpendicular to inclined plane and then solve easily. Is there any way to solve is using...
  5. R

    Spring compression of a bowling ball

    Homework Statement A 5 kg bowling ball moves at 10 m/s on a flat and frictionless surface. It hits a massless bumper with a spring constant of 100 N/cm. How far (in cm) will the spring compress? Homework Equations |F| = |kx| Fnet = ma The Attempt at a Solution This is mostly a plug and chug...
  6. C

    What is the optimum angle to hit a golf ball the furthest?

    Could anyone please tell me how to get this answer through calculations and other means?
  7. C

    Typical Relativity Car and Ball Problem.... ....

    Homework Statement Homework Equations The Attempt at a Solution (a) The person outside of the car will see the car's velocity as being c/√2 and the baseball's velocity as c/√2, therefore the observer in frame S will see those two velocities as added together because they both move in the...
  8. x2017

    Find Coefficient of Restitution with just height of the ball after one bounce

    Homework Statement A ball is dropped from a height of 9.02 m. After hitting the ground, the ball then rebounds to a height of 1.78 m. What is the coefficient of restitution associated with the ball and ground impact? Homework Equations e=(V'-v')/(V-v) The Attempt at a Solution I thought maybe...
  9. M

    Calculate the average resultant force required to accelerate the ball.

    Homework Statement A 56 g tennis ball is accelerated at 1000 m s-2 to reach its service velocity. Calculate the average resultant force required to accelerate the ball. Homework Equations F = MA The Attempt at a Solution Mass = 0.56g = 0.056kg Acceleration = 1000m/s2 0.056 x 1000 = 56N...
  10. A

    What Causes a Ball to Roll Off a Hemisphere?

    Homework Statement A ball is rolling along a frictionless hemisphere with radius R. The question asks about when will the ball rolls off the hemisphere. I understand that this happens when the normal force vanishes. But I am also wondering what if the normal force provided by the hemisphere...
  11. Ethan Godden

    What Happens to the Buoyant Force on a Beach Ball When Submerged?

    Homework Statement 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 completley submerged, what happens to the buoyant force...
  12. E

    Ball in accelerating tank with fluid

    T1. Homework Statement a wooden ball of mass m is kept inside water by the help of a massless string shown in the figure. One end of the string is fixed at the bottom of the vessel. when the vessel containing the water is accelerated upwards with acceleration a , will the tension increase and...
  13. S

    Initial pressure to launch ball at Velocity Z

    1. Problem I have a horizontal cylinder with a ball in it. What must the initial pressure be to launch the ball at Z velocity? 2. Attempt P = F/A A = Surface Area(Cylinder) - 1/2 Surface Area (Ball) = (2πrh) F = m*a U = - ∫ F dx U = 1/2 mv^2 at x = h ∫ a dx = -1/2mv^2 / m at x = h Z =...
  14. Frankenstein19

    Trouble with ball being thrown up in the air problem

    Homework Statement The problem reads: A person throws a ball up in the air with an initial velocity of 15m/2. Calculate the max height reached and how long it is in the air for. Homework Equations x = x0 + v0t + 1/2at^2 The Attempt at a Solution [/B] I need to calculate the how long the ball...
  15. B

    Projectile Motion Soccer Ball Problem

    Homework Statement I saw this in a video about solving projectile motion problems and I was confused, I think I may have seen the same thing in my textbook:The question says: A soccer player on a level playing field kicks a soccer ball with a velocity of 9.4 m/s at an angle of 40 degrees above...
  16. x2017

    What impulse must act on the bowling ball to stop it?

    Homework Statement [/B] A 10kg bowling ball is moving with a velocity of -3m/s. a) What is the momentum of the bowling ball? b) What impulse must act on the bowling ball to bring it to a stop? Homework Equations momentum=mv impulse=ΣFΔt ΣFΔt=mΔv The Attempt at a Solution a) momentum = mv...
  17. aimen khattakk

    Momentum Ball Collision Find Normal Force

    [Note: Thread moved by moderator] Hi! so I have a question I am unable to do and I've been trying it for 3 hours. The question had 2 parts, i figured out part a but cannot figure out part b. A) A 0.006kg ball is dropped from a height of 4.0m above the floor. Neglecting air resistance...
  18. Alexstrasza

    Which ball travels further, up a ramp or thrown in the air

    Homework Statement Two identical balls, one is thrown at angle α up a frictionless surface, the other one is thrown at the same angle up in the air. Both have the same initial velocity. A. Which one travels further? Explain. B. Is the mechanical energy of the first ball conserved? Explain...
  19. C

    Projectile Motion Ball throw Question

    Homework Statement Someone throws a ball 1m from the ground at a 30 degree angle to the corner of the room 8m away and elevated by 1m. Find the initial velocity of the ball. Homework Equations s=ut+1/2at^2 The Attempt at a Solution So i broke it up into vector components in order to find the...
  20. M

    How can you create sustainable plasma without a plasma ball

    I want to do an experiment for a presentation for a medium amount of people. How can I create plasma to show off to them?
  21. DeldotB

    When Does a Bouncing Ball Come to Rest?

    Homework Statement Hello! A ball is dropped and falls to the floor (no horizontal velocity). It hits the floor and bounces with inelastic collisions. The velocity after each bounce is \mu times the velocity of the previous bounce (here \mu is the constant of restitution). The velocity of...
  22. C

    Ball rolling and slipping with backspin

    Homework Statement A solid ball of mass M and radius R and moment of inertia I is placed onto a table with an initial velocity v_0 to the right and angular momentum w_0 anticlockwise (i.e the ball has backspin). Due to friction, the angular velocity and linear velocity changes as the ball both...
  23. RLst

    How can I accurately plot the trajectory of a spinning ball on a spreadsheet?

    Hi everyone, Firstly, sorry if this seems a bit rushed, I don’t have much time in between shifts at work. You may have to refer to my links. But if needed, I will add more information later on. I've been racking my head over this for the last month or so. I’m kinda doing a private personal...
  24. T

    Calculate Speed of Red Ball Falling From 26m

    Homework Statement A red ball is thrown down with an initial speed of 1.3 m/s from a height of 26 meters above the ground. The force of gravity due to the Earth results in the balls each having a constant downward acceleration of 9.81 m/s2. What is the speed of the red ball right before it...
  25. M

    MHB How Do You Calculate the Entry Velocity of a Ball into a Basketball Hoop?

    I am trying to find the velocity at which a ball enters a basketball hoop. The answer should be -6.42m/s at an angle of -43.6 degrees, but idk how to get that. The ball starts at a velocity of 7.67m/s and reaches a max height of 4m. The hoop is 3m high, and the ball starts 2.1m above the...
  26. C

    Throwing a Ball and determining possible angles.

    A man throws a ball horizontally with an initial speed of 20 m/s. Determine the two possible angles theta 1 and theta 2 of release so that the ball strikes point B. The distance between the man and point B is 15 meters. The initial height of the ball is 1.25 meters. Answer: Theta 1 = 5.8...
  27. F

    Getting two Answers : calculating velocity of ball

    Homework Statement Mr. Gale decides to build his own velocity measuring machine. His plan is to build a box (mass 2.50 kg) that catches the ball (mass 0.500 kg) being thrown. It then slides across the desk but eventually comes to a stop due to friction (μ = 0.800) between the box and the...
  28. N

    How to control spin of a launched ball

    Hello, i have to launch a ping pong ball for an engineering course. We have a system set up with two wheels spinning as fast as we can get them and a ping pong ball feeds between them and shoots. Our asignment is to create a model that shows distance shot related to the angle of launch. We also...
  29. K

    How Does Pulling the String Affect the Speed of a Ball in Circular Motion?

    Homework Statement Ball of mass=m on the frictionless table is connected to a string that passes in hole that is in table. The ball is set into a circular motion on a circle of radius = R. If the string pulled from the bottom, withe the force F, so that the radius of motion of ball would...
  30. P

    MHB Prob of red ball in buckets. Binomial?

    I know for many of you this sounds trivial. For me it's not... A barrel contains M buckets each containing B balls, for a total of N = M x B balls. N is a big number. A small number R > 1 of balls are red. All the others N-R are white. The location of each one of these R balls is random...
  31. D

    Throw a ball, initial velocity?

    Homework Statement A referee throws a ball in a basketball game. When the ball was in his hand the heigh was 1,6 meters above the ground. The ball is caught 0.8 seconds later by a jumping player. The ball is 2.7 meters above the ground and on the way down. what was the initial velocity when the...
  32. D

    How does the mass of a ball affect the % of energy loss

    Homework Statement I am wondering how the mass of a ball affects the percentage of energy loss when the ball bounces. Homework Equations Ep=mgh eff=eout/ein x 100% The Attempt at a Solution 1)I don't think it affects them because if the ball is heavier but still made of the same material it...
  33. I

    Deriving the Relative Velocity of a Ball Hit by a Massive Object

    I was thinking about gravitational slingshots so I broke it down to a simple thought experiment: a ball being hit by a massive object. You have a ball of small mass m and a big moving object of large mass M moving at v = 10 m/s. The ball sees the wall approaching at 10 m/s. When the wall hits...
  34. D

    How does mass of a ball affect percentage of energy loss

    I am wondering how the mass of a ball affects the percentage of energy loss when the ball bounces 1)I don't think it affects them because if the ball is heavier but still made of the same material it has the same elasticity and density only mass has changed. But if all of the starting Ep goes...
  35. J

    Is this book wrong? Tennis ball rebound speed

    I am reading a book abut tennis physics and I have seen a result that I feel is wrong. We have a tennis ball and a racket, and several cases: 1.- Ball hitting stacionary racquet that is sustained with your hand. (I agree with the results of the book here, it is just to show how they are...
  36. I

    What is the final velocity of a bouncing ball after hitting a wall?

    I've seen the solution to finding the velocity after a ball bounces off of a wall. http://www.lhup.edu/~dsimanek/ideas/bounce.htm If a ball of mass m1 and velocity v1 hit a massive wall, what is the final velocity. I understand the math. What I find a little confusing is reconciling the math...
  37. D

    Finding Force Applied on a ball from another object

    Homework Statement Another question regarding pool. I need to know how much force applied is given from the cue to the ball as well as force of friction OF CUE: a=56.55m/s2 vi=0m/s vf=3.28m/s d=.0953m m=.55kg BALL: m=.17kg *not sure whether to use distance traveled during contact or of the...
  38. D

    Trouble finding correct acceleration of a ball

    Homework Statement Well I need to find the acceleration of a pool ball after it has been hit by the cue. I measured the final velocity of the cue which was 2.9m/s and its acceleration was 41.42m/s*2. I know that the vf of the cue is the vi of the ball and because the ball has friction after it...
  39. jbm1939

    Ball dropped out a truck window, find bounce height and dist

    Homework Statement A ball weighing 0.2 lbs is dropped out the window of a pickup truck moving horizontally at 45 mph. If the C.O.R. (e) between the ball and the ground is equal to 0.6, find the height of the ball's first bounce and the horizontal distance it will travel before bouncing again...
  40. F

    Determine speed of roulette ball through audio analysis?

    I'm trying to find a way to track the speed of a spinning roulette ball in real time through audio analysis, i.e. have a computer report the speed of the spinning ball it hears through a microphone.Here is a video of a spinning ball: I've tried watching a real time spectrum analyser (FFT), but...
  41. B

    Major trouble with a ball attached to a string on a pole....

    Homework Statement A 0.5 kg mass is attached to a string that is 20 cm tall and anchored to a pole. There is an angle between the string and the pole. 1) What is the force of gravity on the mass in terms of the angle? 2) If the mass is pulled slightly to an angle of 5 degrees and if sin(theta)...
  42. A

    Ball thrown from ISS to earth at right angle to it's path

    Suppose I am on ISS and Earth is exactly below (at the right angle to the ISS's line of path). Now if I throw one ball below towards Earth from window at exactly 90 degrees to the line of path of ISS and one ball upwards at right angle to the line of path of ISS. **Assume normal human strength...
  43. G

    Tennis ball gun, muzzle velocity

    I am designing a tennis ball gun and am trying to work out the forces involved. It is essentially elastic powered but at this stage all I need to know at this stage is this: with the gun at a 20 degree incline what muzzle velocity would result in the ball traveling 50 metres?
  44. Rumplestiltskin

    Velocity Calculation of Kicked Rugby Ball

    Homework Statement What is the velocity of a rugby ball 3.0s after it is kicked vertically upwards with a speed of 16m/s? Give your answer to 2 s.f. Homework Equations SUVAT The Attempt at a Solution s = ? u = 16 v = ? a = g = 9.8 t = 3 Erm... v = u + at? 16 + 9.8 x 3 = 45m/s. Incorrect, try...
  45. David Earnsure

    How fast is ball thrown up to come down in 2 seconds

    Homework Statement Ignoring air drag, how fast must you toss a ball straight up for it to take 2 seconds to return to same level you threw it from. 1. 20 m/s 2. 7.5 m/s 3. 15 m/s 4. 5 m/s 5. 10 m/s Homework Equations vf = vi + a x t The Attempt at a Solution To me this problem seems...
  46. F

    Calculating angle of ball after collision

    Homework Statement The white ball in the figure has a speed of 1.81 m/s and the yellow ball is at rest prior to an elastic glancing collision. After the collision the white ball has a speed of 1.37 m/s. To the nearest tenth of a degree, measured counterclockwise from east, what angle does it...
  47. N

    Calculating Kinetic Energy of a Ball: Is it Possible?

    Homework Statement A ball with a mass of 2.3 kg is thrown into the air. If the ball rises to a maximum height of 15 m before stopping and coming back down, how much kinetic energy did the ball have initially? Homework Equations KE=0.5*mass*velocity^2 The Attempt at a Solution I don't think...
  48. N

    Force measurement from accelorometer in Soccer ball

    I have a 3-axis accelerometer suspended on rubber bands inside a soccer ball and am wondering how to calculate the impact force of the ball with it. I have an intuition that the force will be proportional to the frequency of the oscillations of the sensor after a collision but I am having...
  49. B

    Impulse of a ball being thrown on to the wall

    Homework Statement a tennis ball of mass m = 0.075kg is thrown at a wall with a speed of v = 15m/s. It strikes the wall at a 45˚ angle and rebounds with the same speed at 45˚. What is the impulse given by the wall? Homework Equations impulse = Change in mass x Change in velocity The...
  50. S

    A different bouncy ball question....

    So I've seen all over the internet about the efficiency of a bouncy ball and how high will it bounce on the 2nd, 3rd, 4th, etc. bounces? That's easy to figure out. Now I was thinking about it for a while and the question that hit me was how much energy do I need to add to the initial drop in...
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