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.
Iron ball hanging from a scale and suspended...
Iron ball hanging from a scale and suspended in a glass of water filled to the rim, what happens to the reading of the scale, volume of water, and weight of the glass of water?
The attempt at a solution: there's an FB that's equal to the...
Homework Statement
A rod of mass M is lying on a flat frictionless surface. A small ball of mass m and
velocity v collides with the rod in the center at the rod at right angle to the rod.
The collision is elastic.
Homework Equations
a) Where is the axis of rotation for the rod...
Homework Statement
A tennis ball is thrown upward with and reaches height of 18 m. What maximum height can reach this ball on the where acceleration of free fall is 6 times less than g? In both cases initial velocity is same. [sic] (excuse my physics teacher's grammar, don't shoot the...
Homework Statement
There is a ping pong ball being lifted and suspended in the air by a hair dryer. A.)What is the upward vertical force needed to suspend the ping pong ball? A ping pong ball has a Mass of about 2 grams. B.)If the pressure underneath and inside the ping pong ball is 1 atm...
Homework Statement
a) Find the frequency of vibration under adiabatic conditions of a column of gas confined to a cylindrical tube, closed at one end, with a well-fitting but freely moving piston of mass m.
b) A steel ball of diameter 2 cm oscillates vertically in a precision-bore glass...
given below is a more than one choice type MCQ,
A ball is bouncing elastically with a speed 1 m/s between walls of
a railway compartment of size 10 m in a direction perpendicular
to walls. The train is moving at a constant velocity of 10 m/s parallel
to the direction of motion of the ball...
When reading about entropy it states that ball does not automatically bounce up because of entropy. It is just not favorable.
I don't get this. Isn't the correct reason gravity? Ball does not bounce up because of gravity! Where does entropy come from?
First of all, I want to say that I am totally ignorant about physics. And I do not understand the general concepts of physics at all.
Now coming to the question.
Suppose, you drop a green tennis ball from above.
Now It usually lands on Earth and stop there ( ignore the bounces for...
Homework Statement
This problem is from a homework assignment. The professor says that the the ping-pong ball will go up if the cd = 0 and will go down if the cd is much larger than one. Is this logic correct? I keep thinking about how if an aerodynamic car is pushed by wind, the car...
Homework Statement
A rigid ball of mass m = 6kg and radius R = .23 m is sitting on a table. The mass center and geometric center of the ball coincide, but the radius of gyration about its mass center is k = .19 m. The ball is initially at rest. There is a coefficient of friction μ = .435...
Homework Statement
A ball is dropped from a height of 16 feet. Each time it drops h feet, it rebounds 0.81h feet. Find the total distance traveled by the ball.Homework Equations
The Attempt at a Solution
I don't understand the meaning of this.
$$-16 + \sum_{n=0}^{\infty}(.81)^n= 16+...
Homework Statement
In the figure on the right, a 4.0 kg ball is attached to the end of a 1.6 m rope, which is fixed at O.
The ball is held at A, with the rope horizontal, and is given an initial downward velocity. The ball moves through three quarters of a circle and arrives at B, with the...
Hi, I just need some help with 3 questions that is asked in my rubric for this investigation. I have already done the experiment to investigate the relationship between the height from which a ball is dropped and the height of the resulting bounce
Homework Statement
1) Draw a graph of average...
the question is on here http://imgur.com/z4EFJiO
ignore the silly answer i found it on facebook and started to solve it just for fun and i ended up with...
http://imgur.com/pBkXZIs
sorry for the messy format, but i explained all my calculations (you're going to have to click to enlarge...
Hello,
I'm having trouble with solving for the centripetal force.
Some questions in my textbook don't give the velocity and radius, so the centripetal force is a bit harder to calculate. There are three main scenarios which I am having trouble with:
[1] A girl has a ball in her hand...
[b]1. What would be the effect on the impact force of a lower or higher release point of a metal ball in an inclined plane.
[b]2. I don't know what to do here.. or how to answer. My teacher told us to include formulas to prove our answers.
Homework Statement
Lets say we have a silver ball with radius ##r=1cm## hanging on a string which is an isolator. What is a charge on the ball if we shine on it with a light with ##\lambda = 200nm##? The work function for silver is ##A_0 = 4.7eV##.Homework Equations
\begin{align}
&W - A_0 = W_k...
Homework Statement
Two soccer players kick a ball back and forth toward each other. They start off 50 meters apart, and walk toward each other with equal speeds. They kick the ball continuously until they meet in the middle one minute later. What is the magnitude of the ball’s average...
Homework Statement
A ball is dropped from a height of 16 feet. Each time it drops h feet, it rebounds 0.81h feet. Find the total distance traveled by the ball.
Homework Equations
Geometric series sum of ar^n
The Attempt at a Solution
D1= 16 feet
D2 = 16(0.81) + 16(0.81) =...
Homework Statement
A ball is thrown at 72km/h speed from top of a building. Building is 125m tall.
Homework Equations
Distance traveled before it hit the ground is as follows:
s = Ut + 0.5 gt^2
The Attempt at a Solution
Using quadratic equation:
x = -b±b^2 - 4ac / 2a
The...
Homework Statement
If you swing a ball in a vertical circle using a thin string, at the bottom of the circle the tension in the string must be greater than the ball's weight. True or false?
Homework Equations
F = mvv/r
F = mg
The Attempt at a Solution
The correct answer, it says...
Shuttling ball.
I was told that as the two conductive plates are brought closer together the speed the shuttling ball travels between them is increased. I don't understand this as i thought because the electric field is uniform between plates the distance they are apart wouldn't affect the...
Homework Statement
(context: I'm studying for a test, and this is a question from a past exam paper.)
"A wedge of mass M with angle \phi is free to slide on a frictionless horizontal table. A solid ball of radius a and mass m is placed on the slope of the wedge. The contact between the ball...
Hello,
Just wanted to say I did this today. I could envision it in theory a while.
Went ahead and filed it under creative commons. Wondered If any of you "are" aware if this is a pattent somewhere? And maybe shed some light on it.
We start with arranging neodymium ball magnets in a diamond...
Hi all,
I have a question about how to analyze the problem of a ball rolling down an incline plane. Assuming there is friction, at each instant the ball swivels about a pivot point on the incline that is stationary due to static friction. We then would analyze the torques about this point...
Hello, I would like to share a cool experiment... but not yet experimented for me.
Suppose you have a ball of metal between two plates.
The upper plate is charged - and the lower plate is charged +
There is constant potential between the plates.
When the ball touches the lower plate, it...
Physics Homework Help -- Force when kicking a ball
Homework Statement
I have a few physics problems on my homework, I need help.
A player kicks a 0.5kg ball with a force of 50N, what is the force on his foot?
Homework Equations
F = Mass * Acceleration
The Attempt at a Solution...
Homework Statement
There is a large\infinite amount of balls in a basket to pick from.
Each ball in the basket is with the same probability (33.33...%) either black, white or gray. No other colors exist.
You first pick 4 balls out of the basket.
Then you pick 2 more balls out of...
Hi,
I have a 'simplified' equation of the magnetically suspended ball.
a = g - (i/h * M)
where
a - actual acceleration of the ball.
h - distance from the magnet.
g - gravitational acceleration, to keep it simple let g = 10
M - mass of the ball 0.05 kg
i - current through the...
Homework Statement
Mass of Cue stick : 595 g
Mass of White Ball: 170 g
Mass of Black Ball: 155 g
On the pool table, the white ball bounces off of the black ball and moves in the direction opposite to its original direction. If the speed of the white ball immediately after the collision is...
Hi PF.
I'm currently developing a 2D platform game that is significantly physics-based using the Box2D physics engine.
However, one of my main problems right now is that the main "character" of my game is a ball and unfortunately, Box2D does not support rolling friction. The result is that...
Homework Statement
model the run up a bowler takes before he throws the cricket ball
Homework Equations
model the path of the cricket ball
The Attempt at a Solution
we can make any assumption. if anyone good in physics please helo me model it.
Hi guys, just an intuitive question I've come across. Quite ambiguous, not sure on the correct response.
So basically I'm given a scenario where I'm provided the data of an actual height vs time points of a vertical ball drop and it's bounce up and back down etc.
Question starts off where I...
Homework Statement
Under which class of materials would the following materials be categorized?
What are/is the primary bond type(s) in each material/object?
a. Tennis Ball
Homework Equations
The Attempt at a Solution
We'll consider a very simple and standard tennis ball...
Homework Statement
Homework Equations
Wnon-conservative forces = ΔEnergy
The Attempt at a Solution
I understand that I am to solve for the D in Wnon-conservative forces since I know the friction force. I am just having trouble understanding what the initial/final kinetic...
As stated, the problem is to prove B(x,r) is a subset of B(x',r') if and only if d(x,x')<r'-r, where d is a measure function. The proof going one direction seems pretty simple, but I can not figure out the other direction
Attempt at answer
<=
Assume d(x,x') < r'-r.
Assume a is an...
Homework Statement
Let there be 2 boxes U1 and U2. Box U1 contains 3 red balls and 4 black balls. Box U2 contains 5 red balls and 3 black balls.
We chose at random from one of the boxes:
-If it's a red ball from U1 we put it in U2.
-If it's a black ball from U1 we put 2 black balls in U2.
-If...
Homework Statement
A ball is thrown to a man and reaches him in 60s. The ball curves because it is spinning at an average angular velocity of 330 rev/min on its way to the man's hands. What is the angular displacement of the ball
Homework Equations
θ=ωt
The Attempt at a Solution
I...
I want to know why everything in the universe forms a Ball or Sphere? Is gravity the cause of this? If so why? For example, If we were to pick the sphere apart can we see the source of gravity? Is gravity also a ball or sphere and can we grasp and see it? Why do we not ever see square planets or...
(For recreation)
Assuming (from Wikipedia) that the mass of the Sun is 2 x 10^{30} Kg,
I wondered what would be the size of an equivalently-massed ideal ball of water at STP with uniform density?
I read there the Sun is about 109 Earth diameters. My water ball model calculation is ~123...
Homework Statement
Time tries to crush a 0.85kg basketball, but is only able to compress it by 1.5cm when a force of 50N in applied
a) What is the spring constant of the ball?
b) When he throws it against the floor, it is compressed by 3.4cm. How high will the ball bounce?
Homework Equations...
Homework Statement
a ball was hanging by an inextensible string to a small airplane. firstly, it was hanging straight down but when the pilot started the motor the string made an angle of 30 degrees wrt the vertical.
Assuming that the ball is a point mass, find the acceleration (m/s²) of...
Well, I took my Physics final today, and I passed it but I didn't do quite as well as I'd hoped. Anyway, there was one problem I spent tons of time trying to figure out. I've tried giving it a shot again at home, but it's still eluding me. Some guidance would be great! Sorry if this is...
Homework Statement
A ball of mass m is attached via a rod of length x to an axle that rotates with angular velocity ω. You can consider the ball to be a point mass.
m = 5 kg, x = 0.3 m, y = 0.4 m, ω= 30 rad/s
(a) What is the linear momentum (direction and magnitude) of the ball?
(b) What...
Hey guys, I've been thinking about inertia/forces for a test I have soon and I've been stumped by a question that the teacher gave us a while ago.
Suppose a football is rolling along the ground and you give it a swift kick in a direction perpendicular to its initial motion. In what direction...
Homework Statement
The mass of the ball: 136 G
Length of the slope that its sliding down: 132 Cm
Angle of the slope that its sliding down: 11,5228 °
All I have to do, is to find the velocity, and the acceleration of the ball. Though my teacher has given us no time at all for this project...
Homework Statement
A ball is thrown up , another is dropped. Do they arrive at the same time?
Homework Equations
The Attempt at a Solution
I think they won't because the ball which is thrown up has a greater distance to travel, but I am not sure, can someone explain please?
1. A 560 g hollow ball 18 cm in diameter is suspended by a wire and is undergoing torsional oscillations at a frequency of 0.78 Hz. What is the torsional constant of the wire?
Homework Equations
F=-κθ
ω=sqrt(κ/I)
The Attempt at a Solution
tried to use the frequency to get the angular...
There is a ball placed on a frictionless slope. As we all know that, since there is no friction, the ball will not rotate. But after drawing a free-body-diagram and decomposing the gravity, we find that the net force mgsinθ has a torque relative to the contacting point with the value of mgsinθR...