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. K

    Ball rolling and bouncing from a wall

    Homework Statement A ball of mass m rotates without sliding at velocity v1 and hits a wall. it rotates backwards at velocity v2. what is the energy loss. Homework Equations Kinetic energy of a rigid body: ##E=\frac{1}{2}I\omega^2## Moment of inertia of a ball round it's center...
  2. J

    Physics Practical: Rebound height of a table-tennis ball

    Homework Statement For part aiii), the mark scheme states "Use of set squares to indicate height". I know what are set squares, but how does it aid to determine the rebound height, h? I thought set squares are to ensure two objects are perpendicular to one another? How does it help in...
  3. D

    Average acceleration of impact of ball.

    A ball travels vertically downwards until it hits a concrete floor with speed 16.1-m/s. It then bounces vertically upwards at 3.4-m/s. Examination of a high speed video shows that the collision took 1.1-ms. Considering just the collision, what is the magnitude of the average acceleration? b)...
  4. K

    Ball hitting a hanging rod: Velocity and Energy Loss Analysis

    Homework Statement A rod of length L hangs on a nail. a ball of mass m hits and sticks to it. the rod rotates to angle θ. What is the velocity of the ball and what's the loss of energy. Homework Equations Kinetic energy of a rigid body: ##E=\frac{1}{2}I\omega^2## Angular momentum...
  5. Samei

    Dropping ball into spring (inelastic collision)

    Homework Statement : [/B]I asked a question on this topic before, but I want to make sure I know the material well. So, I looked up another question similar to it (and a little more complex) to check my understanding. Here is the practice problem: A board with mass M, when placed into a coil...
  6. N

    Angle between velocity vectors of 2D billiard ball collision?

    Homework Statement During a game of billiards, a white cue ball traveling at speed v strikes a green ball that was initially at rest. The green ball's speed after the collision is twice the speed of the white ball after the collision. The billiard balls have equal mass. What is the angle...
  7. D

    Capacitor & Pith Ball: Exploring Charge Transfer & Static Electricity

    Suppose I first charge a capacitor so that one plate is positively charged and another negatively. Now I remove the charging source and ground only one of the terminals say negative terminal, will there be a net positive charge in the capacitor that can be detected by a pith ball? Can a...
  8. Bailey

    Falling objects: Tennis ball vs. feather

    Assuming air resistance, when a tennis ball and a feather are dropped from the same height? Which statement is true: A: Tennis ball has more mass so it will fall faster. B: Tennis ball has less surface area so it will fall faster I think the answer should be A, but the textbook say B is true...
  9. N

    Calculating Force Applied to Golf Ball by Club with Limited Data

    Homework Statement You hit a golf ball (mass 50g) squarely with the club face from ground level on a flat golf course. The ball leaves the club at an angle of 20 degrees above horizontal and travels 250m before hitting the ground. The force vs time graph below shows the force exerted on the...
  10. F

    Ball Bearing Speed Calculation in Elevator

    An open elevator is moving with an upward velocity of 0.52ms-1 with an upward acceleration of 2.4ms-2. A ball bearing then rolls off the floor with zero horizontal speed. Determine the speeds of ball bearing and elevator 2s after the ball rolls off the floor. Using v=u+at, speed of ball bearing...
  11. aman patel

    How to create force of 3000 joules to push iron ball of 100gm?

    Respected all my bros,, I want to creat force of 3000 joul to push the iron ball of 100 gm? The ball should go straight upto 10 meters at speed of 700 miles per sec.
  12. nmsurobert

    Charged ball exiting a box....

    Homework Statement A small ball has mass 3.4x10^-8 kg and charge of 2.0x10^-5 C. It enters a box with initial speed 1.2x10^4 m/s. The point where the charge leaves the box is at a voltage 350kV higher than the entry point. Find the speed of the ball as it leaves the box. [/B]Homework Equations...
  13. M

    How Should the Child's Acceleration Be Calculated to Catch the Thrown Ball?

    Homework Statement Starting from rest, a child throws a ball of mass m with an initial speed v , at an angle B with the horizontal direction. The child then chases after the ball, accelerating at a constant acceleration a . If the child wants to catch the ball at the same height as it was...
  14. D

    Archimedes principle with a completely submerged ball

    Greetings, I have a question about the classic Archimede's principle. A ball inflated with air will not sink into water. My understanding is that it will be pushed from all directions by the surrounding water trying to fill the space occupied by the ball. So there will be a pressure downwards...
  15. J-dizzal

    Angular momentum of ball problem

    Homework Statement In the figure, a 0.400 kg ball is shot directly upward at initial speed 40.4 m/s. What is its angular momentum about P, 6.65 m horizontally from the launch point, when the ball is (a) at maximum height and (b) halfway back to the ground? What is the torque on the ball about P...
  16. M

    Solving Three Ball Collision: Elastic Collision with M and m Masses

    Homework Statement Ball of mass M collide two balls of mass m , elastic collision . initially, M has velocity v , and two balls are stationary. after the collision the two masses move ,like in figure , v_a , v_b / What is the velocity V ,of mass M after the collision ? Homework...
  17. S

    Time Dilation with a Tennis Ball

    So I just finished reading my textbook on special relativity and am a bit confused by the discussion of time dilation. We equip an observer with a light source, a mirror, and a clock and herd him onto a train moving at constant velocity relative to a second observer located at the station. If...
  18. BTBlueSkies

    Is the wave function more like a soccer ball, or a golf ball

    I have been trying to understand the wave function around an atom.. Is it more like a soccer ball where the shell is smooth but is more likely to be found in say the dark areas, or is it more like a golf ball where it is not only angularly undulating, but also radially undulating?
  19. M

    What is the Average Power of Energy Loss for a Bouncing Ball?

    Homework Statement A ball bounces down a uniform flight of stairs of height H , rising after each bounce to to the level h of the previous stair . the velocity of the ball before the impact is equal in all the impacts . what is the average power of energy loss ? Homework EquationsThe...
  20. A

    Calculate the force of ball on an incline leaning on a wall

    Hi all, I'm working on a problem from the Feynman exercise book, and have been racking my brains for an answer, so would really appreciate some help here. The problem seems simple enough: A ball with a 3cm radius, weighing 1kg rests on an inclined plane (angle alpha) and also touches a...
  21. srmico

    Ball rolling up a ramp with friction -- Find max height (Unsolved)

    Hello, 1. Homework Statement A spherical continuous ball is sliding with a constant velocity v along a frictionless lane. Thereafter it enters an inclined surface (the angle between the surface and the horizontal plane is α) with the coefficient of friction µ between the ball and the surface...
  22. K

    Calculating angular speed of a ball after collision

    Hi, I've been wondering is there anyway of calculating the angular speed of a ball after there is a collision of it and another mass. For example a baseball bat hitting the ball. I have not looked up on angular momentum, but is angular momentum involved in this? Based on common sense, I think...
  23. K

    Projectile motion of a fired cannon ball

    1. A cannonball is fired toward a vertical building 400 m away with an initial velocity of at 36.9° above the horizontal. The ball will hit the building in A. 4.0 s. B. 5.0 s. C. less than 4.0 s. D. more than 5.0 s. 2. If the cannonball in the previous question is fired horizontally from a...
  24. R

    Ball Hitting Stationary Blocks

    Homework Statement Objects A and C are made of different materials, with different “springiness,” but they have the same mass and are initially at rest. When ball B collides with object A, the ball ends up at rest. When ball B is thrown with the same speed and collides with object C, the ball...
  25. K

    Ball Rotation on a Ball: Solving for Center of Mass Velocity

    Homework Statement A ball of mass m and radius r starts off on top of a fixed ball of radius R. it rotates down without slipping. What's the ball's center of mass velocity as a function of θ. The angular velocity is ω. Homework Equations Moment of inertia: ##I=\frac{2}{5}mr^2## Potential...
  26. J

    Relativity Question: Airliner -- Light & ball movement

    Homework Statement Imagine that you are flying on an airliner on a long flight to Europe at a constant speed of 300 m/s a) you throw a ball towards the back of the plane at 20 m/s. You then shine a beam of light towards the back of the plane. How will these two things i) the ball and ii) the...
  27. Liam Lau

    Why Does a Ball Bounce Lower?

    Homework Statement Why does a ball bounce less and less high, even though the force exerted by the ground on the ball is the same, due to Newton's third law. I do understand the ball loses energy as heat energy. Homework Equations F=ma ; F1=-F2 The Attempt at a Solution I'm just curious why...
  28. T

    Ball with maximum velocity on reaching the ground.

    Homework Statement A ball A is thrown upward to a height H with a velocity of 20m/s, another ball B is thrown down from H with a velocity of 20m/s and a third ball C is just dropped from the same height. Find which ball has the maximum velocity when it hits the ground.Homework Equations...
  29. w3dnesday

    Gauss' law, spherical symmetry

    Homework Statement Assume that a ball of charged particles has a uniformly distributed negative charge density except for a narrow radial tunnel through its center, from the surface on one side to the surface on the opposite side. Also assume that we can position a proton anywhere along the...
  30. M

    Doppler Effect with Swinging Ball

    Homework Statement A ball (like the one used in lectures) generating a sound with a frequency of 594 Hz is swung around in a large circle with a radius of 1.49 m. The time it takes the ball to travel around one complete circle is measured and found to be 0.96 s. the speed of sound in air is 343...
  31. S

    What is the period of a ball rolling on a track with a given height function?

    Hi guys, My logic is obviously flawed here I'm just not sure what I'm missing. I'd love a hint but don't tell me too much as I want to try to figure this out once I'm heading in the right direction :) I'm really upset with myself that I couldn't solve this, so I'd love more SHM problems to...
  32. gen66

    Would I be able to see a ball passing next to me at 340m/s ?

    Imagine a football(soccer) ball passing next to you with a speed of 340 meters per second. Would you be able to see that? I would like to ignore realistic details as the ball burning or leaving trails etc. I'm just interested if I would be able to see the actual ball passing next to me at that...
  33. mesa

    What is the best material for cryo ball mill cup assembly?

    I am working with a set of alloys that must first be ground up in a ball mill at cryogenic temperatures. It is important that no contamination makes it into the material and careful steps are taken to ensure this end. Unfortunately when we ran a set of samples through our RBS lab and then again...
  34. P

    Will house burn down enclosing camera in foam ball?

    Homework Statement This is not exactly homework, but is homework level so this is probably the best place to ask rather than the more learned sections. However, I'm prepared to defer to your better judgement. I want to put a web camera inside a foam ball. The camera is a retail product so...
  35. M

    Conservation of energy in bouncing ball

    Throwing a ball which is (m)kg on the ground If the velocity of the ball just before it reaches the ground is (v)m/s Assume it is a elastic collision The velocity of the ball when it leaves the ground should be (-v)m/s According to conservation of momentum,the ground has a change of...
  36. Puddles

    Finding the Ratio and Height of a Double Ball Drop Collision

    Homework Statement A ball of mass m1 is aligned above a ball of mass M2 (with slight separation), and the two are dropped simultaneously from height h. (Assume the radius of each ball is negligible compared to h.) (a) If M2 rebounds elastically from the floor and then m1 rebounds from M2, what...
  37. RileyF1

    Find x(t) for a ball travelling down a cycloid under gravity

    Homework Statement I want to find the equations of motion for a ball traveling down a cycloid under gravity so I can model the brachistochrone problem on matlab. I've looked online everywhere and can only find the equations for x and y with respect to theta (of the cycloid). I'm guessing then...
  38. RileyF1

    Deriving Position WRT time of ball travelling on curve

    Homework Statement [/B] I'm trying to write a program in MATLAB which demonstrates a tautochrone curve and how the starting point of a ball is irrelevant as to the time it takes to get to the lowest point in the curve (without friction). At the moment I'm just trying to model it using a simple...
  39. Rmehtany

    Friction Direction on Rolling Ball: Am I Missing Something?

    My question is the following. A ball is initially skidding and eventually starts rolling on a flat plane with friction, and later comes to a halt. Which direction does friction act? (see diagram) If friction acts to the right, then the translational speed will go up, and that's not right...
  40. LotusTK

    Will the ball clear the net? - Projectiles question

    There is a question i have done in my textbook and it initially asks you to calculate: the maximum height of the ball, and how long it takes to arrive at that maximum height. They give you a vertical velocity component of 5m/s. So i made an equation using t= (v-u)/a Which gives me...
  41. freutel

    Find the time it takes for bouncing ball to come to rest

    Homework Statement A ball, which is launched in the air with velocity V, has inelastic collisions with the floor: the kinetic energy after each collision is k times the kinetic energy before the collision, where k<1. Assume that the gravitational acceleration is constant: g [m/s^2]. I was asked...
  42. Glenboro

    Projectile Motion of a Cannonball: Calculating Velocity, Height, Time, and Range

    Homework Statement A cannonball is fired with a velocity of 125 m/s at 25.0° above the horizontal a) Determine the horizontal and vertical components of the initial velocity. b) Determine the maximum height the cannonball reaches in its path c) Determine the time it takes to reach maximum...
  43. Glenboro

    Calculating momentum of soccer ball.

    Homework Statement A soccer player, kicking a soccer ball, gives the ball a velocity of +26.8 m/s. The mass of the ball is 0.425 kg, and the duration of the impact is 1.05  10–3 s. a) What is the momentum of the soccer ball after it has been hit? b) What is the change in momentum of the...
  44. md abul hasan

    A ball is thrown upward direction , is it a -ve displacement

    when a ball is thrown in upward direction --how can it be a negative displacement?
  45. mooncrater

    A ball with some energy and yes a string

    Homework Statement There is a question that says: A small bal of mass m is attached to the end of the string of length ##l=1m## whose other end is fixed. From its lower position, the ball is given a kinetic energy ##\frac {mgl}{5}##. Find the net acceleration (in ##m/s^2## ) of the ball at...
  46. M

    Forces acting when we squeeze a ball?

    I have few doubts to clear. I would like to know the forces acting when we squeeze a foam ball. Mode of squeeze will be by placing the ball between the palm of the hand and the four fingers. What will be the force acting at the center of the ball when we squeeze? Is the force same through out...
  47. P

    A 0.5 kg ball sits on a cart

    Homework Statement I am a substitute today for a physics class. I am baffled by the following and could use some help. A 0.50 kg ball sits on a cart. When the cart is pulled to the right by a net force of 3N, friction exerts a force of 2.0 N on the bottom of the ball. The ball rolls without...
  48. E

    Modeling Ball and Spinning System

    How should I go about modelling a ball and spinning beam system in matlab? It's similar to the ball and beam control system except the beam spins like a propeller so the control system has to account for the centripetal force. Any reference papers?
  49. E

    Rotational motion -- Ball rolling back and forth on a U-shaped ramp

    If a ball rolls down a U-shaped ramp from a height h, why does it not reach a height h on the other side? (Frictionless ramp) It will reach a height of (5/7)*h, but I'm not sure why. Some of the potential energy is converted to rotational and some is translational kinetic, but why do they not...
  50. S

    Two people in a boat and one person throws a ball

    1. Two people sit at opposite ends of a boat. Ther person at the front of the boat has a ball and throws it to the person sitting at the back of the boat who catches it. What is the motion of the boat at the time immediaately after the ball is thrown and later after the ball is caught ? Answer...
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