Balls Definition and 555 Threads

  1. B

    How Do You Calculate the Force in Pool Ball Collisions Including Friction?

    I have a bit of time on my hands at the moment and being an avid pool fan I wanted to try my hand at programming a pool simulation. Now I have the balls moving correctly whether they are sliding or rolling but I am having a little trouble getting my head round the collisions. Ideally I want...
  2. V

    What Are the Final Speeds of Billiard Balls After a Perfectly Elastic Collision?

    Homework Statement Two Billiard balls of equal mass undergo a perfectly elastic head on collision (Energy is conserved) . If the speed of one ball was initially at 2.0 m/s and the other 3.0 m/s in the opposite direction, what will be their speeds after the collision?? Homework...
  3. N

    Conceptual question about torque and balls

    [SOLVED] Conceptual question about torque and balls Homework Statement Take a look at the following thread: https://www.physicsforums.com/showthread.php?t=147053 In this thread, the torque is measured from the center of the ball. Can I measure it from the point where the ball and the...
  4. K

    Finding Collision Angles in Pool Ball Refraction

    Hi, I'm currently working on a game of pool/snooker. Its all going great, but i have this problem when the balls hit each other. I can get them to bounce off the walls correctly, but that's because the walls are either vertical or horizontal...hitting a ball is more difficult. At the moment...
  5. S

    Probability of picking one of several balls of one of two colors

    An bag contains four yellow balls and two green balls. Find the probability of getting a yellow ball if you. . . (a) . . . randomly choose a ball from the urn. (b) . . . randomly choose and discard two balls and then choose a third. i know how to do part a..it's just 4/6 = 2/3 but for...
  6. R

    2 balls dropped from a building

    Homework Statement A ball is thrown straight up from the edge of the roof of a building. A second ball is dropped from the roof a time of 1.00s later. You may ignore air resistance. If the height of the building is 21.0m, what must the initial speed be of the first ball if both are to hit the...
  7. B

    Two balls falling and bouncing one off the other

    I'm not sure how to do this. The Problem: http://i1.uploadem.com/11052007/untitled.GIF We have two balls one with mass M and another with mass m. M>>>>>m both balls are dropped at the same time, the heavier ball below the lighter ball from a height of 10 meters. (even though the lighter...
  8. C

    Collision between two balls physics problem

    Two identical steel balls, each of mass 4.3 kg, are suspended from strings of length 30 cm so that they touch when in their equilibrium position. We pull one of the balls back until its string makes an angle θ = 65° with the vertical and let it go. It collides elastically with the other ball...
  9. P

    Final question of the day help finding impulse of two billiard balls

    Homework Statement A billiard ball going 4 m/s collides with a stationary ball of equal size cause the second ball to move at an angle of 35 degrees at speed of 2.5 m/s --mass=.3 kg What impulse (magnitude and direction) did second ball receive? What about the first ball? What is the final...
  10. P

    Final speed of two billiard balls

    Both have mass of .5 kg and speed of 2.8 m/s; collide completely inelastically Do I use the conservation of momentum formula? v2= m1/m1 + m2 * v1? Ugh.
  11. C

    Measuring Elasticity of Balls using Collision Method

    This is quite tricky.. How to measure the elasticity of balls using a collision method? apparatus: air track blower gliders motion sensors (2 sets) 2 tennis balls How do i do this?
  12. A

    Solving Collision of Billiard Balls: Speed and Direction

    Homework Statement Similar to the other one... On billiard ball is shot east at 2.6m/s. A second, identical billiard ball is shot west at .8m/s. The balls have a glancing collision, not a head-on collision, deflecting the second ball by 90 degrees and sending it north at 1.58m/s. What...
  13. A

    What torque will bring the balls to a halt in 5.6s?

    Homework Statement A 1.2kg ball and a 2.2kg ball are connected by a 1.0m long rigid, massless rod. The rod is rotating clockwise about its center of mass at 26rpm. What torque will bring the balls to a halt in 5.6s? Homework Equations T = I(alpha) Wf = Wi + alpha (delta t) I =...
  14. B

    Find the Net Force on Ball A from Balls B & C

    Homework Statement Each ball weighs 3.00 kg A is 10cm from C to the left and B is 40cm to the right of A Homework Equations F=Gm1m2/r^2 The Attempt at a Solution ive tried adding the forces that each ball apply to A and subtracting it. i know each has its own force acting on A...
  15. S

    Collision of B1 & B2: Solving the Homework Statement

    Homework Statement Ball 1 (B1) and Ball 2 (B2) are located at (x,y)=(0,0) and (x,y)=(d,h). At t=0, B1 is sent towards the initial location of B2 with a speed vi. At the same instant that B1 is launched, B2 falls towards the ground with zero initial velocity. Assume there is no air...
  16. G

    Probability of balls chosen from an urn

    Homework Statement An urn contains 3 white and 4 red balls. A ball is chosen at random ( in a frequency sense) and replaced. What is the probability of the first 5 balls chosen exactly 2 will be white. Homework Equations The Attempt at a Solution Really I haven't made much...
  17. R

    Calculating the Free Fall of Two Balls

    Homework Statement Two ball are dropped from 5m high, Use 10 m/s^2 for the magnitude of the acceleration due to gravity. Homework Equations How do i start? The Attempt at a Solution not sure on how to start so i haven't attempted:(
  18. J

    Finding Explosives with 8 Balls & 2 Weighings

    The President is going to a ping-pong match in Tokyo. He is taking 8 balls with him. A terrorist has implanted one of the balls with explosives, but they add such a small amount that no one can tell the difference. The CIA has only enough time for TWO weighings before the match. I...
  19. S

    Solving Physics Problems: Dropped Stones, Thrown Balls, and Falling Tiles

    1. A spelunker (cave explorer) drops a stone from rest into a hole. The speed of sound is 343 m/s in air, and the sound of the stone striking the bottom is heard 1.64 s after the stone is dropped. How deep is the hole? 2. A ball is thrown upward from the top of a 25.0-m-tall building. The...
  20. N

    Collision Time of Thrown and Dropped Balls

    Homework Statement A ball is thrown straight up from the ground with speed v_o . At the same instant, a second ball is dropped from rest from height H - there's no air resistance. Find the time when the two balls collide. The Attempt at a Solution The path of the ball which is...
  21. N

    Finding the momentum of the each balls

    Homework Statement There are two questions. 1) A baseball, m=0.045 kg, moves in +y-direction with v = 5 m/s. a tennisball is moving in the -x direction with speed of 2m/s. Wat is the magnitude and direction of total momentum in the system? 2) A 0.01 kg rifle bullet is fired with v = 500...
  22. S

    What is Ball B's Speed After an Elastic Collision with Ball A?

    Homework Statement Two balls, Ball A on the left, and Ball B on the right, are moving towards each other. Ball A is much bigger and heavier than Ball B. Ball A is moving with speed x, and Ball B is moving with speed y. They collide, and an elastic collision occurs, sending Ball B rebounding...
  23. S

    Question on different masses striking balls

    Everybody knows that if a ball hits an equal mass ball the one that was moving will stop and the other on which was stopped will move, this is the funtioning of Newtons craddles. My question is rather simple: If a 1kg billiard ball at a speed of 1 m/s hits a 2kg still ball, with what...
  24. H

    Unsolvable Ball Weights Problem: Help Needed with 4 Balls and Scales

    My friend asks me this problem, and i fail. It seems unsolvable. Can anyone help You have to use the scales 3 times to identify 4 balls which look identical but with different weights: 1; 2; 3 and 4kg each. Thanks.
  25. L

    How Long is a Ball Thrown Upwards 3m Above Ground?

    Homework Statement A ball is thrown vertically upwards with a speed of 10m/s from a point of 2m above the horiztonal ground. a) Calculate the length of time for which the ball is 3m or more above the ground. Homework Equations v^2=u^2 + 2as v=u+at The Attempt at a Solution So there's...
  26. H

    Pool Ball Grade 12 - Issue Resolved Thanks to Trajan22

    pool balls grade 12 please help issue resolved tyvm to Trajan22
  27. D

    Find the coefficient of restitution between the balls (should be easy)

    Homework Statement i'm retaking a test question for half credit and this is the 3rd part to the question. i know the velocities are correct because the teacher gave us the answers. this SHOULD be simple... but okay.. (velocity) V1 = 20ft/s, V2 = 0ft/s. after the collision V1` = 16ft/s...
  28. E

    Thermodyamics, two balls with same temperature, different elevation

    Homework Statement Two identical balls, A and B, of uniform composition and initially at the same temperature, each absorb exactly the same amount of heat. A is hanging down from the ceiling while B rests on the horizontal floor in the same room. Assuming no subsequent heat loss by the...
  29. R

    What is the maximum height reached by the other ball after collision?

    Two identical steel balls, each of mass 1.4 kg, are suspended from strings of length 36 cm so that they touch when in their equilibrium position. We pull one of the balls back until its string makes an angle q = 36° with the vertical and let it go. It collides elastically with the other ball...
  30. P

    Electrostatics: 3 balls on a string, calculate net forces.

    Homework Statement 3 balls are on a ?string?/line?. Each are equally displaced, 72cm. Ball A has a charge of -50e5c, Ball B a charge of +25e2, Ball C -10e10. 1. What is the net force applied on the middle ball (Ball B)? 2. Assuming a force to the right(ungiven name of Ball D?) (of Ball C)...
  31. C

    Which Arrangement of Charged Balls Results in the Largest Net Force?

    Homework Statement Three balls, with charges of +4q, -2q, -q, are equally spaced along a line. The spacing between the balls is r. We can arrange the balls in three different ways: (1) +4q, -2q, -q; (2) -2q, +4q, -q; (3) +4q, -q, -2q. (a) Which ball experiences the largest magnitude net force...
  32. S

    Two ferromagnetic balls, rolling down a ruler

    Here's the situation: We have a ruler, inclined slightly with a strong ceramic magnet at the end. Now, we put two identical ferromagnetic (steel, for example) balls on the top of the ramp, touching each other. We let the balls roll down the ramp, and, perhaps against intuition, the balls...
  33. M

    What other theories/formulas can be linked to a project on bouncing basketballs?

    hi all I'm doing an experimental investigation for a school project on bouncing basketballs. I've linked this project with kinetic and potential energy (i.e I've written how kinetic and potential play a role in the resultant rebound height) and I'm wondering if anyone knows any other...
  34. R

    Calculating the required energy for throwing a tennis ball into space

    hello i would really like to figure out the amount of energy one would reuqire to throw a tennis ball into space hypothetically speaking? i understand that this is impossible but i would like to find out anyway. i would be very grateful if anybody could help me with this. thankyou
  35. G

    Electric Fields and Styrofoam balls

    Here is the question: Three identical small Styrofoam balls (m = 1.93 g) are suspended from a fixed point by three nonconducting threads, each with a length of 49.0 cm and with negligible mass. At equilibrium the three balls form an equilateral triangle with sides of 29.2 cm. What is the common...
  36. G

    Inelastic collision of two soccer balls of different masses

    You might or might not have seen the astro blaster. But if you drop two soccer balls (stacked together) you'll notice that the smaller top soccer ball lifts up to great heights. I am researching this phenomenon for my extended essay and would really appreciate it if you guys could provide me...
  37. D

    Exploring Metric Space and Nested Balls: A Surprising Result

    I need to find a complete metric space and a sequence of nested, closed balls such that their infinite intersection is empty. How is this possible?
  38. S

    Sliding/rolling billiard balls

    Hi, I have got a bit stuck on some basic principles to do with the motion of a billiard ball, and was hoping someone could point me in the right direction! Assuming I have the linear velocity and angular velocity of a uniform billiard ball (with the centre of mass exactly in the middle), how...
  39. P

    Stop Evaporation & Heat Loss with Anti-Evaporation Balls | Explained

    Can anybody tell me if there is a technical name for the balls that are used to float on a liquid surface to stop evaporation and heat loss? Thanks
  40. D

    After how long will the balls be at the same height?

    Can somone please walk me through how to do this problem. I've been going at it for wat too long: A ball is thrown upward from the ground at an inital velocity of 25 m/s; at the same instant, a ball is dropped from rest from a building 15 m high. After how long will the balls be at the same...
  41. Aquafire

    What Defines a Planet?

    When is a Planet a planet...? and when is it just a ball of gas..? My personal belief is that Jupiter, Saturn, Neptune and Uranus...should NOT be considered planets. How can you call a spheroid ball of rotating gases a planet ? Surely, if you can't step on it, land on it or float on it...its...
  42. K

    Elastic Collisions of steel balls

    Here's the problem: "Two steel balls are suspended on (massless) wires so that their centers align. One ball, with mass 2.30 kg, is pulled up and to the side so that it is 0.0110 m above its original position. Then it is released and strikes the other ball in an elastic collision. If the...
  43. D

    Balls and Boxes Complicated Problem

    Consider a set box boxes. Say we have 30 boxes. And then we have x number of black balls and y number of white balls And these balls are stacked in the boxes. The total nuber of ways of stacking them is easy to find, but a much harder problem is to find the probability that for anyone of...
  44. Amith2006

    Mass of spherical balls after adding charges

    # Two identical spherical balls A and B are given equal amount of positive and negative charge. What is the ratio of the masses A and B now? a)Equal to one b)Greater than one c)Less than one d)May be Greater than or Less than one depending on their sizes
  45. E

    Looking for a 3D graphics program to draw balls in space

    Is there exist a program that I just give the (x,y,z) coordinates, and the program draw me a 3D ball where I asked. I will use it to draw a crystall consisting of balls. I need the program to help me visualize the structure of a crystal, and to draw a picture of a crystall, and identify the...
  46. B

    Probability Distribution of 4 Balls: Mean & Variance

    an urn contains 4 red balls and 4 white balls an experiment consists of selecting at random a sample of 4 balls and recording the number of red balls in the sample setup the probability distribution and compute its mean and variance i know what a probablity distribution is. can someone please...
  47. H

    Optimizing Bowling Ball Speed: Comparing 15 lbs and 16 lbs Balls

    I think this is a fairly basic question, but I have been out of physics since high school. Let's assume that I have two identical bowling balls, except that one is 15 lbs and the other is 16 lbs. If we avoid discussion about ball rotation and friction on the lane, how much additional speed...
  48. T

    Mechanics Question of two balls

    Mechanics Question :) Hi. Two small balls A and B have masses 0.5kg and 0.2 kg respectively. They are moving towards each other in opposite directions on a smooth horizontal table when they collide directly. Immediately before the collission, the speed of A is 3m/s and the speed of B is 2...
  49. L

    Name of the pendulum thing with five balls suspended on strings?

    Hey guys I know you're probably going to laugh at me for this question, but what is the name of the pendulum thing with five balls suspended on strings? You know, the thing that every boss has on his desk in every movie? I have been trying to figure it out for a while now.
  50. L

    Pressure of balls bouncing on area

    a 5g balls fall dropped from 3m bounces up 1m. if 100 such balls fall on an area of 2m^2 every second what is the average pressure exerted by the balls? ive tried to solve this problem 100 different ways and i can't get the answer (3Pa).
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