Balls Definition and 555 Threads

Homework Statement There is total of 300 balls in the basket, 30 of them is red (rest is white). If we picked up, randomly, 4 balls, what is the probabilty that all of them is red ? 2. The attempt at a solution For one picked ball, probability that it's red is 30/300 = 1/10. If...

If a cylinder is rolling without slipping, C is the centre of zero velocity for a moment and O is the centre Does the angular rotation about O equal to the angular rotation about C, or is there only one angular rotation when a cylinder is rolling, that is the rotation about the point of...

I am working on a hobby project. I need 2 perfectly spherical, perfectly balanced, pure metal (ie. pure titanium, aluminum, etc.) balls made, and then I need one (the larger one) to be precisely drilled through the center. It is essential that everything is done in an extremely accurate manner...

Homework Statement I know about Plasma Balls (generally) from this site: http://www.4physics.com/phy_demo/plasma1.htm But I need to somehow explain what is occurring in this demo where a fluorescent bulb is lit up when in the vicinity of the plasma ball: Homework Equations None that...

Homework Statement A pendulum of mass m_1 is released at an angle theta_1 and strikes the pendulum of mass m_2, which rises to angle theta_2. The coefficient of restitution e for the two masses is given. Derive an expression for the angle theta_2. Homework Equations KE_1+PE_1=KE_2+PE_2...

Homework Statement near the surface of the Earth there is an electric field of about 150 V/m which points downward. 2 identical balls with mass 0.540 kg are dropped from a height of 2.0 m, but one of the balls is positively charged with q1 = +650 uC and q2 = -650 uC. use conservation of...

Homework Statement A Bag contains 4 balls.two balls are drawn at random,and are found to be white.what is the probability that all balls are white? Homework Equations P(B/A) = P(A intersection B) / P (A) The Attempt at a Solution A = Two balls are white. B = All four balls are...

Homework Statement Two billiard balls, one heading north at 15.0 m/s and a second heading south at 10.0 m/s, collide head-on. Take the collision to be perfectly elastic and choose the positive direction north. What is the post-impact speed of the first ball Answer: m/s What is...

Homework Statement Consider an elastic collision (ignoring friction and rotational motion). A queue ball initially moving at 2.6 m/s strikes a stationary eight ball of the same size and mass. After the collision, the queue ball’s final speed is 1.2 m/s. Find the queue ball’s angle (theta)...

Homework Statement There's a rod, 1 m long and by itself weighing 1 kg, with two balls attached at each of the sides, one weighing 2 kg, and the other 4 kg. The balls are put upon two scales. What force is applied upon each of the scales (e.g. what do the scales show)? Homework Equations...

The questions is pretty short... The source was a chat session and hence the simple sentence. I am stuck with this and thought that Homework Help doesn't attend out of the way questions and so I'm asking them here.

Hi everyone. I wasn't really sure where to put this thread so I stuck it here, which seems the closest fit. Anyway I've been thinking about this for too long: what characterises the unit ball of a norm? Let's be specific: consider a finite-dimensional vector space, which may as well be...

Homework Statement A pool ball with initial speed v is aimed right between two other pool balls (looks like: 0 -> : if the semicolon were two balls and were touching each other). If the two right balls leave the elastic collision with equal speeds, find the...

Hi guys, first time in this forum. seems legit. I'm in year 12, i have to find or make a EPI (prac) to do with one of these topics. 1. Co-efficient of friction between different surfaces. 2. Strength of nylon/cotton/steel/tin string. 3. Projectile motion. 4. Bending of a beam. 5. The...

Homework Statement A pool ball with initial speed v is aimed right between two other pools balls. If the the two right balls leave the elastic collision with equal speeds, find the final velocities of all three balls. Homework Equations Equations for Energy and Momentum conservation...

Homework Statement Estimate the number of Ping - Pong balls that would fit into a typical-size room (without being crushed). In your solution state the quantities you measure or estimate and the values you take for them. (Assume 25% of the space cannot be filled due to spherical packing.)...

Homework Statement Specifically, How many ways can you divide up 20 distinct balls into 5 distinct boxes so that no box contains more than 10 balls? Homework Equations This is similar to another problem in which we have to find the number of ways to divide up r balls into k boxes...

Homework Statement Give an example of a decreasing sequence of closed balls in a complete metric space with empty intersection. Hint 1: use a metric on N topologically equivalent to the discrete metric so that {n≥k} are closed balls. In={n,n+1,n+2,...}. Homework Equations N/A The...

Homework Statement Ball A is dropped from the top of a building of height 'h' at the same instant that Ball B is thrown vertically upward from the ground. When the balls collide, they are moving in opposite directions, and the speed of A is twice the speed of B. At what height does the...

Homework Statement A 0.0600 kg tennis ball, moving with a speed of 2.50 m/s, has a head-on collision with a 0.0900 kg ball initially moving away from it at a speed of 1.00 m/s. Assuming a perfectly elastic collision, what is the speed and direction of each ball after the collision...

box A has place for 2 balls, box B has place for 3 balls balls are placed randomly in each of the boxes until one of them is full if X is the amount of balls used, find: E(x) var(x) i drew the boxes and think there are only 3 options,,, X=[2 3 4] BOX A --- BOX B I) 2 balls...

4 balls are placed randomly into 10 bins, what is the probability that exactly 8 of the bins will be empty?? first i need to find out how many ways i can place the balls into the bins --> 10*10*10*10=10000 now i need to find how many ways the balls can be placed so that there are 8 empty...

Homework Statement Let (X,d) be a metric space and let A be a non-empty subset of X. Prove that A is open if and only if it can be written as the union of a family of open balls of the form Br(x) = {y ∈ X|d(x,y) < r} (the radius r may depend on the point x). Homework Equations...

http://fatcat.ftj.agh.edu.pl/~i7matras/hej.jpg Both masses are in point. I need to count displacement x(t) but I don't know how to write derivative equations? Could someone help? Or at least give me a tip?

Physics of "Hurricane Balls" Two ball bearings are welded together, placed on a mirror, and blown upon using a straw. The RPM's reportedly can reach 10,000 rpm's. There are numerous vid links, here's one: http://www.liveleak.com/view?i=d5c_1179564591 Anyway, I know this can also be done...

Suppose there are 8 balls in line on a horizontal table. Another 2 balls collide them from left side(both approach together) with velocity v. The last 2 balls(from right) get knocked off with the same velocity as that of the balls that approached first.Why don't all the 8 balls move with a...

It has always been explained to me that balls curve because a thin layer of fluid adheres to its surface as a boundary layer. This boundary layer retards the flow on one side of the ball and speeds it on the other. And then Bernoulli's principle is applied to make the pressure difference happen...

In R, every nonempty open set is the disjoint union of a countable collection of open intervals. (Royden/Fitzpatrick, 4th edition) What is the most general setting in which every open set is a disjoint union of countable collection of open balls (or bases)? In R^n? In metric spaces? In second...

I was spending an incredibly exciting Friday night playing with some magnetic "bucky balls" that I got from thinkgeek yesterday. As I am playing with the balls (heh), I have them aligned where I have two sheets, with opposing force. and I was pressing them together imagining the particle...

Homework Statement Question Reads: " A passenger in a hot air balloon throws a ball with an innitial unknown velocity. the ball accelerates at 9.8m/s down for 2.0s. at which time its instantenous velocity is 24m/s [45 below the horizontal]. determine the balls innital velocity "...

Homework Statement A ball was projected at an angle A to the horizontal. One second later another ball was projected from the same point at an angle B to the horizontal. One second after the second ball was released, the two balls collided. Find the speed of projection for the two balls...

Homework Statement A box has 10 bass, 6 are black and 4 are white. Three balls are removed from the box, color unknown. Find the probability that a fourth ball removed will be white. Homework Equations The Attempt at a Solution I got: \frac{4}{10} * \frac{3}{9} * \frac{2}{8} * \frac{1}{7}...

Homework Statement Two small balls with masses 3M and M hang on elastic massless rubber bands (with the M ball attached to and suspended beneath the 3M ball with one rubber band; the 3M ball is suspended from the ceiling by a separate rubber band). When the band between the balls is cut...

Homework Statement Attached to each end of a thin steel rod of length 1.00 m and mass 6.80 kg is a small ball of mass 1.15 kg. The rod is constrained to rotate in a horizontal plane about a vertical axis through its midpoint. At a certain instant, it is rotating at 43.0 rev/s. Because of...

If a ball is thrown upwards, another straight out, and another downwards, which will reach the ground with the highest velocity? After thinking about this for a while my conclusion is that they all will have the same velocity since they all have the same initial gravitational potential energy...

two balls with known mass, radios, and distance between each other, are attract, due to gravitational force. how much time will it take them to reach each other? this is NOT homework... just something i thought about, and have no idea how to solve. (pay attention the mass and radios of each...

I am a little lost on where to begin with this problem. In my mind, it has something to do with a 90 degree angle, so it would require the use of sin or cos. But I may be wrong. Any help would be appreciated. It is due tonight. Problem: A 20 g ball of clay traveling east at 4.5 m/s collides...

Homework Statement Two small balls are suspended side by side from two strings of length L so that they just touch when in their lowest positions. Their masses are m and 2m, repectively. If the left ball (of mass m) is pulled aside and released from a height h, it will swing down and...

An urn contains b blue balls and c cyan balls. A ball is drawn at random, its colour is noted, and it is returned to the urn together with d further balls of the same colour. This procedure is repeated indefinitely. i) What is the probability that the second ball drawn is cyan? ii) What is...

which will strike the ball at the fastest speed? -one launched upward at a certain angel -one launched downward -one launched perfectly horizontally I am guessing 1, since it has the additional height to fall under gravity influence

Hi everyone, this is a problem I posted here a month ago but it wasn't given any attention from the helpers here. I still cannot solve it. So I will greatly appreciate any help. 1. Homework Statement Three small balls of masses m, 2m and 3m are placed on a smooth horizontal surface so that...

Homework Statement Two Styrofoam balls with the same mass m = 7E-8 kg and the same positive charge q are suspended from the same point by insulating threads of length L = 0.92 m. The separation of the balls is d = 0.024 m. What is the charge q? I am unable to add a graphic at this time...

Homework Statement Two metal balls A and B of negligible radius are floating at rest on Space Station Freedom between two metal bulkheads, connected by a taut nonconducting thread of length 1.30 m. Ball A carries charge q, and ball B carries charge 2q. Each ball is 1.66 m away from a bulkhead...

Homework Statement Assume each ball is loosing charge at a rate of 1.20nC/s, as what instantaneous relative speed do the balls approach each other initially. m=11.2g L=122cm x=4.70cm http://img40.imageshack.us/img40/9708/electballs.jpg Homework Equations I figured since the value...

Homework Statement A recipe calls for 1.75cups of melted chocolate. All you have in the cupboard are solid chocolate balls measuring 5/16inch in diameter. How many chocolate balls do you need to melt? ( V_{sphere} = \frac{4}{3} \pi r^3 ) The Attempt at a Solution The attempt is...

Hallow I want to know why if I throw 2 balls and one ball is bigger and whit more mass Why the two balls arrive to the ground in the same time This is the experiment of glilio glili Also I search after more experiment in mechanics (physics) like this Or like this experiment - if I throw a...

https://www.youtube.com/watch?v=yxHrLzvUNZc

Homework Statement You are given a jar with 9 balls in it. 4 of which are red, 3 are green, and 2 are blue. The 9 balls are taken out of the jar one by one. What are the odds that the first 3 balls have 3 different colors? What are the odds that the last 3 ball have 3 different colors...

Hi there, can anyone help me with this problem, I'll be grateful to received your help. It was like this, we were doing an experiment on collision and this is how it goes; We place a ramp on table and a sheet of paper at the bottom of the table but close to the edge. Then we put two...

Hi All, I conducted some experiments on snooker balls and am trying to find the coefficient of restitution between the balls. For the sake of the experiment, I have stated that the balls are sliding rather than rolling, and from an earlier experiment, I have discovered that there is a...