Balls Definition and 541 Threads

The problem I have here is that I can't see how the restitution coefficients (e) will change the trajectory of the ball since the speed of the ball B will be on the same direction as the normal component. And without information one the ball A, I can't see how to resolve that. I will really...

Homework Statement Consider a set of boxes, each containing 20 balls. Suppose every ball weighs one pound, except that the balls in one box are all one ounce too heavy or one ounce too light. A precise scale is available that can weigh to the nearest ounce (not a balance scale). By selecting...

Two objects of the same shape (say balls) fall through the Earth's atmosphere. For simplification, let's say that the air density is the same (some average sea level value) despite altitude change. One ball has considerably bigger mass than the other, but besides that, they're the same. Will...

I am reading a proof that claims that ##\overline{B_{\epsilon /2}(x)} \subseteq B_{\epsilon}(x)##, where the overline means closure, without really explaining why. It's clear to me that ##B_{\epsilon /2}(x) \subseteq B_{\epsilon}(x)##, but I can't quite see why the former is the case without...

I was thinking about this and couldn't really figure it out. You are standing on a cliff and you have two identical balls. In this case, air resistance is to be ignored. The only thing different is that you throw the ball horizontally at different speeds. Let's say you threw ball one at a speed...

Homework Statement Homework EquationsThe Attempt at a Solution i just don't know from where to take the R which is colored with brown, in the 2(MR^2), what is the R here exactly, because i took the radius of the sphere , but i get different answer althought it's near.

Assuming equal mass billiard balls and elastic collisions, classical physics shows that after any collision the motion of the colliding balls will be orthogonal. How does that situation change under SR ? More generally for an elastic collision between objects m and M with m<M, is maximum angle...

This problem appeared in a problem set which I encountered on the internet In a game, balls are labeled by integer numbers. One chooses three different integer numbers between 1 and 10. Two balls are picked at the same time, at random from a box. If they are part of the three earlier chosen...

Hello! (Wave) At a clock (on which we have the positions $1,2, \dots, 12$) we place at position $1$ a blue ball and at position $2$ a red ball. At discrete times ($1,2,3, \dots$) we shift the two balls. Each time we shift the blue ball by three positions and the red ball by one position. Will...

Homework Statement Two small balls, each of mass 5.0 g, are attached to silk threads 50 cm long, which are in turn tied to the same point on the ceiling, as shown below. When the balls are given the same charge Q, the threads hang at 5.0° to the vertical, as shown below. What is the magnitude...

Homework Statement which ball reaches at the end of the board first, which ball reaches ground first, which ball would be fastest when reached ground and at the end of the board? heights are same and balls are identical Homework EquationsThe Attempt at a Solution i think since ball rolls...

I don't really know how to fit what i want to this template, but i'll try. The thing is that i wonder if anyone can explain to me step-by-step what happened in this solution, because i don't really understand it. Homework Statement There are two balls. Upper one(mass m, charge Q) hung on a...

Hello! I have the following problem and attempt for solution. Two equal, small conductive balls hang on two long non-conductive threads attached to a hook. The balls are charged with the same charges and are located 5 cm apart. One of the balls will now be decharged. What is the new distance...

1. Homework Statement in picture Homework Equations momentuma+momentumb=momentum of system The Attempt at a Solution So i just spent 1 hour trying to solve this problem and got completely stuck when trying to solve for the angle of ball 2 in the final position i ended up with an equation...

Suppose we have two boxes, each containing three types of balls. On each ball there's written a number: First box: 1, 2, 3 Second box: 4, 5, 6 We don't know how many balls of each type there are, but we know the probability of taking out a specific one, so that we can make a graph showing the...

Homework Statement Two pith balls each have a mass of 1.0g and equal charges. One pith ball is hung from an insulating thread. The other is fixed at a horizontal distance of 3.0cm from the first, The first hangs at an angle of 30.0° from the vertical. Find: a) the gravitational force on the...

Homework Statement So I've been stuck on this exercise for a few hours now, maybe you can help out: 3 balls meet at the same height hm. Ball 1 is accelerated straight up into the air for 1s from height 0. When the acceleration stops, ball 2 is launched straight up from height 0 with v2 =...

Hi, I'm struggling with a basic probability question and I need some insight into this problem. I can solve the problem, but its a really inefficient and time consuming way. The problem: There are 10 blue balls and 2 red balls in a jar. Calculate the probability of drawing 2 red balls if 4...

Homework Statement Consider 2 balls A,B on the same line . and they are connected to a third one G with a rope L. AG, AB. now the system monves in the effect of the mass of G and its projection to the line AB is in the middle. No friction. mass of A=mass of B=m and mass of G=2m .FInd the time...

Homework Statement Consider 2 balls A,B on the same line . and they are connected to a third one G with a rope L. AG, AB. now the system monves in the effect of the mass of G and its projection to the line AB is in the middle. No friction. mass of A=mass of B=m and mass of G=2m .FInd the time...

Homework Statement Bob had a box containing 9 green balls and 1 white ball. A Bob's friend removed one ball from the box without telling Bob what was its color. Now what's the probability for Bob picking up one green ball from the box? Homework Equations [/B] Not aware of "formulas", I just...

Homework Statement 1.[/B] two balls are thrown vertically from two points on a building. at the bottom of the building ball 1 is thrown and from the roof ball 2 is thrown. ball one reaches its maximum height after three seconds and ball two after one second. after two seconds the balls cross...

Dear all, I've always had, for some reason, mental problems with combinatorics. Somehow I'm missing something (a vital brain part or whatever). The situation I want to analyse for myself, is the following. I want to divide 4 indistinguishable balls over 4 boxes. In the end I want to calculate...

Homework Statement Homework Equations I consider four directions from the point of throwing the balls, east, west, up, down. At any given time, the balls will be at different distance from this point, (the upward ball will travel less distance than the downward ball). So, it could not be a...

Homework Statement Homework EquationsThe Attempt at a Solution The length of the rod is along y direction and (A+B+rod) is traveling along +x direction . Since there is no external force along x direction momentum is conserved along x direction . If v' is velocity of CM of (A+B+P) then 2mv...

Homework Statement Say you're bowling and you roll the ball down the lane. The bowling ball has just knocked the first bowling pin forward and that pin's forward velocity is now much larger than the bowling ball's velocity before their impact. How can the pin travel forward faster than the ball...

In an Elastic Collision in free space with no gravity or friction of two solid balls of radius r1 and r2 I need to calculate the momentum and kinetic energy of the induced spin with angular velocity w1 and w2 to solve for the Conservation of Momentum and Kinetic Energy. Spin Angular Velocity w1...

If an object is thrown vertically upward from a height of h_0 feet with an initial speed of v_0 feet per second, then its height H (in feet) after t seconds is given by h = -16t^2 + vt + h One ball is thrown vertically upward from a height of 50 feet with an initial speed of 40 ft/sec. At the...

Homework Statement Attached. Homework Equations I=mr^2, I=(1/12)m*l^2 for a rod. The Attempt at a Solution Part A I got by doing I=(1/12)3.5*(2.6)^2+2*.7*1.3^2 (I added the moment of inertia of the rod and the balls). Part B since the axis is on one of the balls, I thought we don't include...

Hey! :o I am looking at the following and need some hints: A lottery wheel contains five red, blue and yellow balls. For each color the balls are labeled with the numbers $ 1,2,3,4 $ and $ 5 $. A good fairy draws from the lottery wheel two successive balls. A ball which has already been drawn...

Homework Statement Homework EquationsThe Attempt at a Solution the answer for no adjoining _W_W_W_W_W_ for 3 red balls, there are 6 positions so ## 6C_3 = 20## i'm curious, on other way to find arrangement? for adjoining = all arrangement - adjoining all arrangement = 3 red can get to any...

Homework Statement Homework Equations I have thought about using the momentum formulas here. The Attempt at a Solution As the momentum is a conservative quantity, I have thought that p (before collision) = p(after collision). Since p (before collision) = 12, I wanted to use that result to...

Last week I went to a state fair which I saw a game of lucky draw. There is two sealed boxes, contains bunch of 4 different color balls: red, blue, green and white. Here is the game rule. Players make an initial draw on box one, if players get a white ball, lose the game; if getting a red one...

Homework Statement A tennis ball and basketball are dropped from a height of 1m (the tennis ball on top of the basketball). The tennis ball has a mass of 75g and the basketball has a mass of 1kg. When dropped separately, the tennis ball bounces to a height of 0.5m and the basketball to a...

There are two identical ball,ball A with velocity v and ball B is at rest. Ball A hit ball B directly. How will the two balls move after the collision? In my mind there are three cases: 1. Ball A stops and ball B moves with the velocity v. 2. Two balls move together with same speed v/2. 3. Two...

Homework Statement A super cue ball is made of the same material with the target ball (radius r) but slightly larger: rc = (3)^(1/3)*r The cue ball collides with the target ball on a frictionless table, as shown below, with initial speed of v0. The collision is not head-on, as shown below. a)...

Can anyone explain this "mathematically"? i.e. how to calculate the time in each cases?

Homework Statement Three identical balls fit snugly into a cylindrical can: the radius of spheres equals the radius of can, and the balls just touch the bottom and the top of the can, If the formula for the volume of a sphere is V = 4/3 PI * radius * radius * radius, what fraction of the...

Assume both billiard balls have same mass and same radius. So situation 1: ball 1 is moving forward without slipping on a surface and collides elastically with ball 2 which is stationary on that same surface. I read that immediately after the impact, ball 1 stops and keeps spinning with its...

Homework Statement I have N balls and B baskets. I look at each basket i in turn and decide with some probability P_i whether to insert one ball. After N balls are inserted, I stop. If I look through all the baskets B , I stop; I do not make a second run-through, even if all the balls haven't...

Homework Statement Homework Equations MaVa1 + MaVb1 = MaVa2 +MaVb2 The Attempt at a Solution I found Va2 = 2 m/s e is found to be 1.75, correct?

Imagine you have two identical metal balls, each carrying the same amount of charge, but with one ball being positive and the other negative. When you bring them close together, there will be polarization, so you can no longer treat the balls as point charges. How does one find the charge...

A very neat video showing a phase transition in rotating balls in a cup. Serves as a good analogy to other phase transions.

So I saw the post with the Bernoulli math, but playing with my grandsons in the leisure pool we have observed a ping pong ball released from about 12 inches below clear the surface of the water by an unmeasured inch and a half. And when the twelve year old swims to the bottom of the four foot...

An urn has 5 black balls ans 4 white balls in it. We randomly choose a ball, and return it to the urn, until we get 2 balls with the same colour. What is the probability that the first ball was white, if we know that the last one was white ? I tried building a tree, and realized that the...

The ancient Great Pyramid of Giza had a base of 230.4 meters, and a height of 146.5 meters. A ping pong ball has a diameter of 40 millimeters. The volume of the Great Pyramid = (b^2 x h)/3 = (230.4^2 x 146.5)/3 = 2,592,276 cubic meters. The diameter of a ping pong ball is 40 millimeters =...

Homework Statement In how many ways can 12 balls be arranged into 4 different rows with each row having at least one ball (a) if the balls are identical? (b) if there are 6 identical red balls and 6 identical blue balls? Homework EquationsThe Attempt at a Solution a) Put 4 balls in each row...

< Mentor Note -- thread moved to HH from the technical physics forums, so no HH Template is shown >[/color] i am doubting my solution to this problem , therefore i hope someone assists me a bit . it's simple , there is a bucket that contains 5 red balls and 3 white balls , a player picks up 4...

Homework Statement Ball A is thrown vertically by speed 40 m/s. After 1 second, Ball B is thrown vertically also by speed 47.5 m/s. What height from ground will they pass each other? ( g = 10m/s2 ) Homework Equations s = vt + ½at2 t = v/g v2 = v02 + 2asThe Attempt at a Solution Time A to...