Balls Definition and 555 Threads

Homework Statement Two billiard balls of equal mass undergo a perfectly elastic head on collision. If one ball's initial speed was 2.00 m/s, and the other's was 3.00 m/s in the opposite direction, what will their speeds be after the collision? Va = 2 m/s Vb = 3 m/s Homework...

Conditional probability & "r balls randomly distributed in n cells" Homework Statement I'm posting this in hope that someone can give me a correct interpretation of the following problem (problem V.8 of Feller's Introduction to probability theory and its applications VOL I): 8. Seven balls...

Homework Statement A 5.0-kg object has a velocity of 6.0 m/s, east when it explodes into two 2.5-kg objects. After the explosion one of the objects has a velocity of 4.0 m/s at an angle of 50° north of east. What is the magnitude and direction of the velocity of the other object after...

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 1.14 later. You may ignore air resistance.A- If the height of the building is 19.3 , what must the initial speed be of the first ball if both are to hit the ground at the same...

I typed the question and my attempt at a solution below... It seems obviously open to me, but I'm not sure how to state it using open balls considering that it's in R^2.

If 2 similar pith balls of mass m are hung from a common point with the help of 2 long silk threads. The balls carry similar charges q. Assuming theta is very small find an expression for x. Also assuming that each ball loses charge at a rate of 1*10^-9 c/s at what instantaneous relative speed...

Homework Statement Two metal balls of mass m1 = 2 g (diameter = 2 mm) and m2 = 6 g (diameter = 6 mm) have positive charges of q1 = 2 nC and q2 = 7 nC, respectively. A force holds them in place so that their centers are separated by 8 mm. What will their velocities be after the force is...

Homework Statement Three identical small Styrofoam balls (m = 1.95 g) are suspended from a fixed point by three nonconducting threads, each with a length of 52.1 cm and with negligible mass. At equilibrium the three balls form an equilateral triangle with sides of 28.3 cm. What is the common...

Homework Statement You have 3 urns: Urn 1 has 3 red balls, Urn 2 has 2 red balls, 1 blue ball. Urn 3 has 2 red balls 2 blue balls. You pick a ball from each urn and place it into Urn 4. You draw 2 balls from Urn 4 and they are red. What is the conditional probability that the 3rd ball is also...

Feynman's lecture on physics: chapter 4 derives equation for gravitational potential energy by a "lifting 3 balls" example. The book notes: "But the strange thing is that, in a certain way of speaking, we have not lifted two of them at all because, after all, there were balls on shelves 2 and...

Any idea where these space balls came from? Its speculated that several such balls have dropped in southern Africa, Australia and Latin America in the past 20 years.

I can't seem to find a description online, other than that they're used for neutron energy measurements.

I'm tasked with creating an egg protector that bounces. I'm thinking of gluing bouncy balls together side-by-side around a template sphere. The glue being used should be very strong, it's a super glue that works on rubber. Would this be able to bounce effectively? Will I need to add mass...

Hi guys, I just joined so I could ask a question on something about which I've been curious for quite a while. Imagine a shot in snooker whereby the white ball hits a red, and that red was already touching another red. The result of the shot is that that second red gets fired away like a...

Homework Statement A ball is thrown vertically upwards at 5 m / s from a roof top of 100m. The ball B is thrown down from the same point 2s later at 20 m / s. Where and when will they meet. Homework Equations S = So + ut + 1/2at^2 The Attempt at a Solution well at first I...

Homework Statement Two small balls of the same mass and shape are attached by a massless string of length L. Ball A is placed on a frictionless table and ball B is held a distance L/2 over the edge with the string taut. When ball B is dropped, will it hit the side of the table before A...

Suppose there are two conducting balls of the same radius and the balls are separated by some distance. If both balls are at the same nonzero potential and the potential at infinity is zero, does a closed form formula for the potential exist? Since I can't find the problem solved anywhere I...

A bag contains a total of 50 balls (10 red, 10 blue, 10 green, 10 black, 10 white). If I draw x balls from the bag, what is the probability that the largest number of balls that are the same color is y? For example, if I draw 7 balls, and I get 4 Blue, 2 Green, 1 Red, y=4 It'd be nice if you...

Homework Statement I want to analyse two colliding balls, rolling flat on a billiard table. I have recorded two collisions from above the table. A 1D collision and a 2D collision. In both collisions only 1 of the balls are rolling before the collision. Known is: mass of the balls: m1=207g...

Dear forum I have set AS physics (in england) coursework where the students drop squash balls at different temperatures and measure the bounce height. Yes, I know it is mentioned a lot but haven't so far found a good explanation. Their results will show that the higher temperature...

Homework Statement A wrecking ball is commonly used to destroy old buildings. The energy comes from a motor pulling a large pendulum back, which then allows it to swing against a wall. Why not just use the motor to do the same work on the wall? 2. The attempt at a solution The kinetic...

Hi, I'm an online poker player and i need some help modeling a promotion that the site where i play offers. I think it's rigged and intend to prove it but I'm short on skillz. The promotion is described here and i already made a model but can't solve it. It goes like this: Supose you have...

Hi there :) Homework Statement I am currently preparing an experiment for IB physics, and I need some help planning how I'm going to carry it out. We were given the topic "Balls and Rubber Bands", and we could choose freely upon the exact research question. I personally chose "How does the...

I have a 15 balls and 8 bins. Each bin can only hold 4 balls. If throw the 15 balls in the bins (random) and all the balls land in the bins, how do i find the distribution of balls/bin. eg. #4 bins with 3 balls, #1 bin with 1 ball etc. Thanks!

Homework Statement I already have the solution to the problem. Just need some help deciphering the logic behind it. There are V balls, which are identical except for their color. N of them are blue and V-N are red. We place the balls inside a box so that V/2 balls are on each side...

Homework Statement The problem is given in the picture: (please refer to the 2 pictures below, thank you!) I'm having trouble with the last part... Homework Equations Conservation of momentum in both x and y - directions. The Attempt at a Solution From symmetry it can be seen...

While learning about limit points the use of an open ball has been of high discussion. Why can you not use a closed ball to define a limit point? If someone could give me some intuition as to why I think I may get it. Thanks.

Homework Statement two students throw identical tennis balls towards a building at the same speed. one ball strikes the wall, bouncing back at half its original speed. the other ball smashes a window and continues in the same direction at half its original speed. did the two tennis balls...

Homework Statement Two billiards balls of equal mass move at right angles and meet at the origin of an xy coordinate system. One is moving upward along the y-axis at 2.0 m/s, and the other is moving to the right along the x-axis with speed 3.7 m/s. After the collision( assumed elastic), the...

Homework Statement I recently posted a bingo probability problem, and you guys helped me get an correct answer. Now I have a different problem: 6 balls (can be) are distributed into 12 boxes. What is the probability that the 10 boxes are empty? Simple enough, right? Well its giving me...

Two identical, perfectly smooth 71.2 {\rm N} bowling balls 21.7 {\rm cm} in diameter are hung together from the same hook in the ceiling by means of two thin, light wires, as shown in the figure. The balls are touching with an angle of 50 degrees between the two wires split evenly between the...

Homework Statement This was an example given in class but I didn't understand how the answer was derived. Suppose we draw 3 balls without replacement from an urn with 2 red, 2 green, and 2 blue balls. Define the following random variables: R = number of red balls drawn G = number of...

Homework Statement Suppose that Joe draws k balls from and urn containing n red balls and n green balls, without replacing the balls after they are drawn. Similarly, Mary draws k balls from an urn containing m red balls and m green balls, without replacing the balls after they are drawn. We...

This problem has been giving me problems for the past two days and I can't figure it out :( please help. this is my first ever physics class. Homework Statement A rubber ball is shot straight up from the ground with speed v_0. Simultaneously, a second rubber ball at height h directly above the...

There are 2 radioactive balls, which have the same radius and the same weight. They are covered with absorbing layer. They are made of diffrent materials, with other half-life. What is the easiest way to recognise which is which? I had searched for the answer for a longer time and could not...

Hi, I came across this question which i couldn't figure out why the kinetic energy of the table-tennis ball is greater than the bowling ball after collision. Qn: A table-tennis ball is thrown at a stationary bowling ball. The table-tennis ball makes a one-dimensional elastic collision and...

Homework Statement There are n distinct balls, and n distinct boxes, and one right order for the boxes to be in. What is the chance that none of the balls are in the correct box. And each ball can go into only one box. Homework Equations The chance that none of the boxes are in the correct, is...

Homework Statement Say you have 5 identical balls. You want to put them into 4 different boxes. What is the total number of ways the balls can be arranged? For example, you could have all 5 balls in one box. You could have 3 balls in one box and 2 balls in another, etc. Homework...

Nvm, I figured it out. Thanks anyway.

Homework Statement An urn contains four colored balls: two orange and two blue. Two balls are selected at random without replacemen, and you are told that at least one of them is orange. What is the probability that the other ball it orange? Homework Equations Now, we have been...

EDIT: MASS OF CANOE IS ACTUALLY 50G I typed it wrong the 1st time :/ Homework Statement 50kg girl sits in a 50kg canoe at rest on the water. She holds two 10 kg cannon balls. she throws them over the stern of her canoe one at a time, each ball leaving her hands at a velocity of 5.0m/s...

Homework Statement A ball is thrown at angle \Theta and another ball is thrown at an angle (90-\Theta) with the horizontal from the same point with velocity 39.2 m/s. The second ball reaches 50 m higher than the first. Find the heights. Homework Equations v = u -gt where v is the...

1. You drop a ball from a window located on an upper floor of a building. It strikes the ground with speed v. You now repeat the drop, but your friend down on the ground throws another ball upward at the same speed v, releasing her ball at the same moment that you drop yours from the window. At...

A blue ball is thrown upward with an initial speed of 23.5 m/s, from a height of 0.9 meters above the ground. 2.9 seconds after the blue ball is thrown, a red ball is thrown down with an initial speed of 11.9 m/s from a height of 31.4 meters above the ground. The force of gravity due to the...

Homework Statement A bowl contains w white balls. One ball is selected at random from the bowl; its color is noted, and it is returned to the bowl along with n additional balls of the same color. Another single ball is randomly selected from the bowl (now containing w+b-n balls) and it is...

A ball is thrown straight up from the ground with speed v0. At the same instant, a second ball is dropped from rest from a height H, directly above the point where the first ball was thrown upward. There is no air resistance. How to I find the time at which the two balls collide. A how do I find...

Find the number of distributions of 5 distinct balls into 2 red boxes and one blue box if the two red boxes are identical and no boxes are empty. So First I assumed that the boxes were all identical and got 5!/(3!2!)+5!/(2!2!2!) =25 from there I multiplied 25 by 2 because there are 2...

Homework Statement Two marble spheres of masses 30 and 20 grams, respectively, are suspended from the ceiling by massless strings. The lighter sphere is pulled aside, as shown in the diagram, through an angle of 75° and let go. It swings and collides elastically with the other sphere at the...

Some friends and I were out at a pub last night and this question came up. If you were in space and you had two balls. You threw one ball in one direction at half the speed of light. You through the other ball in exactly the opposite direction then relative to each other they would be traveling...

I've heard many times of the first systematic study of static electricity: Otto von Guericke would spin a ball made of sulfur and rub it by hand, building up an electric charge. To make a sulfur ball, he would pour molten sulfur into a hollow glass globe, wait for the sulfur to harden, then...