What is Ball: Definition and 999 Discussions

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. E

    A ball rolling up a parabolic ramp

    1. Assume there is gravity and no external force acting on the system. A ball has an initial velocity of 5 m/s and climbs up a parabolic ramp, which is defined by y=(x^2)/3. If the ball rolls exactly along the path of ramp and energy of the ball is conserved, starting from (0,0), calculate the...
  2. D

    What is the final linear speed of a basketball rolling down an incline?

    Homework Statement The image above shows a basketball (a thin spherical shell I=⅔ mR^2) rolling don an incline of height 8.4 m. If the ball is already rolling with an initial linear speed of 3.0 m/s then what will be the final linear speed when it rolls off the incline? Homework Equations I =...
  3. J

    Displacement-Time Graph of a bouncing ball

    Homework Statement Does anyone know how to plot a displacement-time graph that will give the average velocity of a bouncing ball? The ball bounces 5 times and I would like to know it's average velocity. What equations would I use? Homework Equations 0.5mv^2=mgh? The Attempt at a Solution I...
  4. B

    Perfectly Elastic Collision and final velocity of ball

    Homework Statement Two balls collide in a perfectly elastic collision. Ball 1 has a mass of 3.5kg and is initially traveling at a velocity of 5.4m/s. It collides head-on with stationary ball 2 with mass 4.8kg. Determine the final velocity of ball 2. Given: m1=3.5kg vi1=5.4m/s m2=4.8kg...
  5. Titan97

    Loss in energy of a ball dropped in a fluid

    Homework Statement Two identical balls A and B are dropped from rest into a tall column of viscous liquid. Ball A is dropped from the surface of the liquid while ball B is dropped from a small height ##h## above the liquid. Let ##E_A## and ##E_B## be the loss in mechanical energy of bal A and B...
  6. P

    Projectile motion: find distance a ball would land

    Homework Statement I'm trying to come up with an equation to determine where a ball would land (basically the distance it moves) from a spring loaded projectile launcher set up on a table. I'm looking for "d", and I know the spring constant, compression, mass of the ball, height the ball starts...
  7. J

    How does friction create spin in a tennis ball

    Homework Statement So I have to do a report about tennis and about the spin. I understand how the magnus effect works and how the ball will bounce but am still unable to figure out how the actual spin is created by the contact with the racquet and the moving ball Homework Equations T=Fr The...
  8. M

    Calculating Velocity Vector for Cue Ball Collision

    Homework Statement I need to find the velocity vector of the cue ball. I know the start-coordinates, end-coordinates(when it hits the red ball), and the time it takes for the travel, but i have no clue on how to make the vector. start(21, 0) end(21, 12) time = 0.1seconds not sure if...
  9. A

    Finding deceleration of a ball?

    Homework Statement How to find deceleration of a ball that is hit, given the ball: mass=0.1kg F=20N is hit by a bat for 0.01s has an acceleration of 200ms^-2 when hit by bat speed=2m per sec travels 0.01m as it is being hit by the bat Was initially at rest.Homework Equations a=(v-u)/t The...
  10. totomyl

    Ball is thrown vertically upward from a window

    Homework Statement A ball is thrown 2.8m/s vertically upward from a window that is 3.6m above the ground. calculate the amount of time the ball spends in the air. Homework Equations quadratic equation d = Vi(t) + 1/2(a)(t)2 The Attempt at a Solution d = Vi(t) + 1/2(a)(t)2 3.6m =2.8...
  11. B

    Kinematics problem: Ball rolling off ramp & table

    Homework Statement http://imgur.com/0t8TVgq http://imgur.com/0t8TVgq [Image copy inserted by moderator] Sorry about all the erase marks. My question is why is the final velocity not 0. Homework Equations V=Vo+at[/B] The Attempt at a Solution So the question is asking for the horizontal...
  12. A

    Working out tension of string holding a ball underwater

    I have a physics homework question that i need help with; A submerged ball of negligible mass is attached to the bottom of a swimming pool by two strings as shown. The volume of the ball is 5000cm^3. Calculate the tension in each string. (hint you need to look up the density of water) How do i...
  13. I

    Closure of Open Ball in Normed Vector Spaces

    Homework Statement Show that ##\overline{B(a,r)} = \{ x \in \mathbf R^n ; |a-x| \le r \}## in ##\mathbf R^n## for all points ##a \in \mathbf R^n## and ##r>0##. Is it possible to generalize the statement to any normed vector space? Give a example of a metric space where the statement is not...
  14. fantisism

    What Determines the Normal Force on a Ball in a Loop-the-Loop?

    Homework Statement A 150 gram ball slides down a smooth track with no friction, which has a circular loop with radius 20 centimeters. The ball has an initial speed of 3 m/s. Its initial position is 80 centimeters above the lowest point of the circular loop. Calculate the normal force of the...
  15. K

    Ball rolls without sliding in a concave bowl

    Homework Statement Ball of mass m and radius r rolls without sliding in a bowl of radius R. Express it's angular velocity ω as a function of the angle θ. What are the normal force and friction force as a function of θ. Homework Equations Moment of inertia of a solid ball round it's center...
  16. J

    Ball rolling down a ramp, no slipping, + friction (conceptual question)

    So if a ball is rolling down a ramp and not slipping, you have two torques... the mg*sin(theta) portion of gravity and the (mu)mgcos(theta) for friction. My question is this: Does this friction force remove energy from the ball? (I know it affects the balls rotation but this is just changing...
  17. Einstein's Cat

    I Papers on 4D ball through 3D space

    Could anyone please recommend any papers that describe the path of a 4D ball through 3D space?
  18. U

    Temperature change of Water after dropping a ball into it

    Homework Statement Suppose we drop a lead ball of mass M into water of mass m from a height h and allow everything to settle down. What is the temperature change of the water? Assume that the container is well insulated. Homework Equations Potential Energy = mgh dU = mcdT where dU is the...
  19. i_hate_math

    Question on Sliding/rolling spherical ball

    Homework Statement A bowler throws a bowling ball of radius R = 11 cm along a lane. The ball (the figure) slides on the lane with initial speed vcom,0 = 7.8 m/s and initial angular speed ω0 = 0. The coefficient of kinetic friction between the ball and the lane is 0.13. The kinetic frictional...
  20. Claire Augustus

    Project Help - Mousetrap catapault to launch cut tennis ball

    Homework Statement "Take a tennis ball and cut it into 2 equal halves. Take one of them and cut it again equally. You now have 1 half tennis ball and 2 quarter tennis balls. Glue the 2 quarters to the half, one to its outside (convex) and one to its inside (concave). Design, build and test a...
  21. O

    Tennis Ball Collision Homework Solution

    Homework Statement A 0.060 kg tennis ball, moving with a speed of 2.50 m/s has a head on collision with a 0.090 kg ball initially moving toward it with a speed of 1.00 m/s. Assuming a perfectly elastic collision, what is the speed and direction of each ball after the collision? Homework...
  22. Wandelgart

    Funny similarities between a ball and the expanding universe

    A rubber ball is bouncing on a flat surface. Every time it bounces, it loses energy, while the sound of the ball hitting the surface accelerates (because the intervals of the ball impacting the surface become shorter with each bounce). The ball seems to be accelerating when, in fact, it is...
  23. Biker

    Solving the Stacked Ball Drop Homework

    Homework Statement A tennis ball has a mass of 75 g that is placed above a basketball has a mass of 590 g. Both are stationary and They were dropped from a height about 1.2 m ( The collisions are perfectly elastic) 1) Calculate the speed of the basketball when it reaches the ground 2) Calculate...
  24. O

    Looking for ball bearing assembly with easy disassembly

    Hi folks! I am looking for a ball bearing assembly that can be easily taken apart and re-assembled. I'm trying to test some ball bearings (the balls themselves) so its advantageous to have a housing that I can easily take apart and reload with a different type of ball without damaging anything...
  25. A

    Short Webpage Title: Ball Toss Free Fall Equations

    Homework Statement Two students are on a balcony a distance h above the S street. One student throws a ball vertically downward at a speed vi ; at the same time, the other student throws a ball vertically upward at the same speed. Answer the following symbolically in terms of vi, g, h, and t...
  26. L

    Electric field at a point inside of a uniformly charged ball

    As the name of the thread says, I am wondering what would the amount and the direction of the electric field at some point in the uniformly charged ball of radius R(it has a constant charge volume density) be at the distance r from the centre of the ball. Does anyone know what would they be? I...
  27. P

    Rotational Motion of a bowling ball

    Homework Statement A bowling ball is released with speed V and no rotational kinetic energy. After a period of sliding and rotating, the ball enters pure rotational motion. The coefficient of friction between the ball and the ground while sliding is Uk. a. Show that the rotational acceleration...
  28. tink7718

    Initial height of a bouncing ball and energy lost

    I am doing a lab in my senior physics class (IB HL Physics 3-4) and I am very confused about a relationship that I found. For my experiment I dropped a racquetball from different heights and then used video analysis to find the height of the ball on its final bounce. I used this data to...
  29. J

    What is the momentum and velocity of each ball after hit?

    Homework Statement A 3.50 kg ball with a velocity of 10.00 m/s collides with a stationary ball with a mass of 5.00 kg. After the collision, the first ball travels at a 42.6 degree angle from its original path, while the second ball travels at a -26.7 degree angle from the other ball's original...
  30. S

    Double ball drop and conservation of momentum

    Homework Statement The classic double ball drop question: a ball of mass m is placed directly above another ball of mass M, and assume that m is not negligible. Both balls are dropped simultaneously. Find the mass m such that, upon the second collision (m with M), M has a final velocity of...
  31. K

    Calculating Force Exerted on Table Legs by Mass and Dimensions

    A ball of mass 15.47kg rests on a table of height 0.73m. The tabletop is rectangular with a mass of 12.11kg, supported by 4 thin legs. The width of it is 134.0cm and length of 63.7cm. If the ball touches the tabletop at point (67.0cm, 16.4cm) relative to corner 1, what is the force the tabletop...
  32. J

    What is the momentum and velocity of each ball after the....?

    Homework Statement A 3.50 kg ball with a velocity of 10.00 m/s collides with a stationary ball with a mass of 5.00 kg. After the collision, the first ball travels at a 42.6 degree angle from its original path, while the second ball travels at a -26.7 degree angle from the other ball's original...
  33. vjanandr

    Pressure inside a basket ball

    International basked ball games are played with a basket ball inflated to 8 PSI. But I am curious to understand how it can stay inflated when the atmospheric pressure is 14.7 PSI. So shouldn't the external atmospheric pressure overcome the pressure within the ball ? Shouldn't the air pressure...
  34. JulienB

    Rolling ball goes through a loop-the-loop....

    Homework Statement Hi everybody! Here is a classical mechanics problem about a ball (mass m, radius r) rolling down a slope (from height h) and going through a loop-the-loop. a) What is the minimum height h from which the ball must roll in order to successfully complete the loop-the-loop...
  35. R

    Pumpkin/bowling ball launcher questions:

    I'm trying to figure out a way to get better results in a "pumpkin launching" contest. The goal is to launch an 8-12 lb pumpkin (or bowling ball) as far as possible.One method is going to use elastic, bungee or large rubber/latex bands as the method of propulsion. The problem is there are...
  36. S

    MHB Choosing a ball at random from a randomly selected box

    I got this probability question as homework, but I got very confused as I didn't know if I should calculate the balls in the 2 boxes as whole or if I should calculate the probability of the first box then add the probability of the second. Any help is appreciated. Thanks.Here is the question...
  37. 2

    A ball is swung in a circular path

    Homework Statement A 0.5 kg ball is swung in a circular path from a 80 cm long rope, attached to a vertical pole. A. What is the speed of the ball theta (between the pole and rope) is 40 deg? B. What is the KE of the ball at theta = 40 deg? C. The ball slows down and the KE drops to 50% of the...
  38. M

    Energy Loss of a ball falling off the lip of a ramp

    Homework Statement This is a Lab: A Ball is placed on a 14cm high ramp and it rolls down to the bottom of the ramp and onto a table where it rolls 20cm (the ramp's horizontal displacement is 16.5cm). After rolling on the table, the ball falls off the table for 76.5cm with a forward horizontal...
  39. blueray101

    The maximum deformation of the ball?

    Homework Statement Part 1: I've worked out part 1 already. The answer is 4650m/s^2 A ball travels vertically downwards until it hits a concrete floor with speed 22.7-m/s. It then bounces vertically upwards at 10.8-m/s. Examination of a high speed video shows that the collision took 7.2-ms...
  40. heartshapedbox

    Describe the angular momentum of the ball and net torque on

    Homework Statement At the instant illustrated, which best describes the angular momentum of the ball and net torque on the ball, as measured around the origin? L⃗ is in the kˆ direction, ⃗τ is 0. Homework Equations torque= (F)x(r) Tension in rope= (mv^2/r)+qvbThe Attempt at a Solution I am...
  41. B

    Rotational Energy, ball on a loop

    Homework Statement Imagine a ball with moment of inertia I_{cm} = \beta MR^2 encountering a circular loop of radius R_0 > R after rolling on a level surface at a speed of v_0. Assume that the ball does not slip. Attached a diagram. A) What is the minimum value of v_0 required for the ball...
  42. RaulTheUCSCSlug

    Calculating the Mass of a Half Ball with Given Density δ(x, y, z)

    Homework Statement If the density of the half-ball x ^2 + y ^2 + z ^2 ≤ 4 ; z ≥ 0 is given by δ(x, y, z) = ( x^ 2 + y^ 2 + z ^2)^(1/2) find its mass. Homework Equations ∫∫F⋅ds ∫∫FoΦ(u,v)||Tu,Tv||dudv ∫∫FoΦ(u,v)⋅(Tu,Tv)dudvThe Attempt at a Solution For the last problem I was asked to find the...
  43. J

    Acceleration of golf club hitting a ball

    The great Ben Hogan said he learned from a physics book when he was on the PGA Tour that if the golf club head is still accelerating AFTER it has struck the golf ball, the result is a straighter shot on line to the target. I can't find any examples of what he is talking about in the physics...
  44. Eclair_de_XII

    How to find the time for a ball with (v_i=/=0) to drop?

    Homework Statement "In a jump spike, a volleyball player slams the ball from overhead and toward the opposite floor. Controlling the angle of the spike is difficult. Suppose a ball is spiked from a height of 2.30 m with an initial speed of 20.0 m/s at a downward angle of 18.00°. How much...
  45. vinamas

    Calculating the Radius of a Metallic Ball

    Homework Statement A mettalic ball is dangling from a light thread connected to an object that is floating on water the objects length is 6 cm and its area is 12 cm^2 and its density is 0.30g/cm^3 if the floating part of the object is 4 cm what's the radius of the ball (the balls density is...
  46. 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...
  47. 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...
  48. 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...
  49. 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...
  50. 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...
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