Roll Definition and 179 Threads

Alrighty-then:smile:Homework Statement This is from a book called "Engineering by Design." It sucks. Really. It asks problems and doesn't provide sufficient information to answer them. Now that I have complained, here is the question: Explain with sketches why a combination of rotations...

http://www.reuters.com/news/video?videoId=84561 I don't have sound so what does the Reuters vid say?

(1) How do you identify Ground roll on a shot record? Is it just the polarized nature of the ground roll that leads to its recognition on a shot record? (2) What is the importance of the Fresnel zone? and What does it depend on?

Homework Statement A cylinder (R= 0.11 m, I (center of mass)= 0.015427 kg*m2, and M= 1.48 kg) starts from rest and rolls without slipping down a plane with an angle of inclination of Theta= 26.3 deg. Find the time it takes it to travel 1.51 m along the incline.The attempt at a solution...

Starting from rest several toy cars roll down ramps at different lengths and angles. Rank them according to their speed at the bottom of the ramp from slowest to fastest. Car A goes down a 10m ramp inclined at 15 degrees, Car B goes down a 10 m ramp inclined at 20 degrees, car C goes down a 8...

Homework Statement 12 different dice are rolled. How many outcomes will have at least one of each number 1,2,3,4,5,6 occurring? The Attempt at a Solution I don't even know where to go because I really don't know what the question is asking. Does it mean how many rolls (where each roll is...

Simple question but not such a simple answer. If I place a piece of toilet paper so that it is just touching the surface of a bowl of water, the water will move up the toilet paper. I know the paper is "absorbing it" but how does it work? What is making it counteract gravity?

Let X be a random variable representing the number of times you need to roll (including the last roll) a fair six-sided dice until you get 4 consecutive 6's. Find E(X)? answer is 1554. I get confused with this, probability { X > n-5 }. I know that the last for throws must be 6's and the one...

Hello, Well i am trying to conduct an FEA on roll cages. I found that the usual materials used for Roll cages (According to FIA regulations+not) were: 1) CDS Carbon Steel 2) ERW Mild Steel 3) DOM Mild Steel 4) Cr (Chrome Molybdenum) Steel Now i was...

I am designing a Roll Cage (Using CAD+FE) and trying out new materials for testing/analysis. Commonly used materials i found are: * CDS Carbon Steel * ERW Mild Steel * DOM Mild Steel * Cr (Chrome Molybdenum) Steel * T-45 * 1020 Grade Mild Steel CDW Anybody...

Hello, I am hoping to build a model rocket with a roll control system for my senior project. Since the idea of building or obtaining a wind tunnel seems infeasible I will need to theoretically calculate how this rocket will behave with various canard fin angles and at various air speeds. I...

60 efolds with no inflaton, no slow roll, no reheating---QEG's apt to be right QEG predicts the Einstein-Hilbert action of General Relativity. don't have to put it in by hand Starting with zero entropy it predicts the right amount of entropy after inflation. (essentially the measured CMB...

I am not an engineer and my math skills are not great but I have this problem that I would like to know the answer to. We have a blister packaging process that seals labeled tyvek against formed pvc blisters that contain our product. What I would like to be able to do is figure out how many...

Homework Statement A climber of mass 72 kg can stand on a rock sloping at 40degrees to the horizontal. What can you deduce about the coefficient of static friction between his boots and the rock? ________________________________________________________ I'm really lost on this one. His...

Hello, I need some help in resolving a dispute. Recently, a friend of mine told me that the probability of rolling a 6 on the second roll of a die after not rolling a 6 is not 1/6. He believes it is not 1/6 but rather the probability of rolling 6 after not rolling a 6 increases with each...

Homework Statement A 30cm diameter wheel rolls without slipping at 120rpm. The point of contact with the ground has an instantaneous speed of: a-5.2mm/s b-1.04cm/s c-2.6 m/s d-zero Homework Equations I'm not really sure about my final answer but i think is d-zero because i have a...

Not sure if this is a diff geom. question or more appropriate for the strings forum or even relativity or cosmology. I'm doing work involved in inflationary models for compact spaces and the two important quantities are the slow roll parameters \epsilon and \eta. Previously I've been using...

I want to calculate the roll of a car going around a turn that is bank 24 degrees at a velocity of 160mph and a track width of 50 inches. TO be honest I am not sure where to start with the data I am given. It would seem to be a simple dynamics problem

https://www.physicsforums.com/attachment.php?attachmentid=7470&stc=1&d=1155157461 spool.JPG Q: if the thread(see attach) is pulled in the direction shown, which way will the spool roll? i know that the spool will roll to the right according to Newton's law (for every action there's an equal...

The "Roll and grow" Oh my god as we speak i am looking at a commercial for a "roll out garden". Yes, you heard it here, just like buying a modular lawn at the hardware store, you can now just buy a roll of seeds/"nutrients" and water it and it'll grow a garden on the little strip. Respect...

hey, well I am doing a project and the title is 'investigating how the distnce traveled by a ball bearing rolling down a slope affects time taken' so basically how the distance of travel (independent variable) effects the time taken to reach the end of the ramp. and, the ball starts from rest...

A small solid marble of mass m and radius r will roll without slipping along A loop-the-loop track, if it was released from rest somewhere on the straight section of track from what initial height h above the bottom of the track must the marble be released so that it is on the verge of leaving...

A gyroscope of a certain size is mounted midship of an SUV of about 2100 lbs, and the gyroscope was setup to accelerate if this SUV accelerated. Now normally if a SUV makes a 90 degree turn past 35 miles per hour the driver looses control and or the vehicle rolls over. How fast would...

The radius of the roll of paper is 7.6 cm and its moment of inertia is I = 2.9 10^-3 kg · m2. A force of 3.2 N is exerted on the end of the roll for 1.3 s, but the paper does not tear so it begins to unroll. A constant friction torque of 0.11 m · N is exerted on the roll which gradually brings...

I'd be willing to bet that no one else can comment on so many threads and not make a bit of difference to the overall "information quotient" I just like to talk and get lonely sometimes.

Curious, since dice have varying indentations per side(one, two, three, four, five, six), is a dice(die?) not more apt to settle with the single "one spot" down on the table?

A certain teacher at my school who teaches compters always says "Magnetism is the future". He says that by utilizing the magnetic fields of planets as "energy boosts or a trampoline" for travel at c+. I explained this is impossible, according to SR a while back, but I backed off (because he was...

OK here's a question which I really, really can't understand. A large, cylindrical roll of tissue paper of initial radius R lies on a long, horizontal surface with the outside end of the paper nailed to the surface. The roll is given a slight shove (initial velocity is about zero) and...

I've been thinking for a while about a Sci-fi series. Sort of trek like but with more believable concepts. Since the arrival of "Enterprise" I think there is room for a good show. This is the idea. At some time in the not too distant future, there is some sort of world disaster (not too...