Rhett Allain reports: Bob Riggle is 80 years old and he has a car. This car has a 2,500 horsepower engine mounted in the rear. But what happens when you have this much power? Yes, you can see in the video that there are two events. First, the car does a “wheelie” and second the car rolls over.
Fortunately no one was injured, but at least this is a great opportunity for a physics lesson.
Center of Mass and Wheelies
There are some forces acting on this car so let’s start with a diagram.
There are essentially three forces on the car in this case.
- The gravitational force pulls down. We can model this force as though it was only pulling down at one point. We call this point the center of mass (technically, it would be the center of gravity—but on the surface of the Earth these two points are at the same place).
- There is the force that the ground pushes up on the car. Since the car is not accelerating in the vertical direction, this ground force must be equal to the gravitational force.
- The friction force pushes on the tire at the point of contact with the ground. This force pushes the car in the direction that it is accelerating.
But how does this car stay tilted up like that? Shouldn’t the gravitational force make it fall back down? Clearly, it doesn’t. Perhaps the best way to understand this wheelie is to consider fake forces. We normally consider forces as interactions between objects (between the ground and the car or between the Earth and the car). However, it’s sometimes useful to create other forces that are due to accelerations. Now, these are fake forces in that they are not a real interaction. But as viewed in an accelerating reference frame (like inside the car), it is as though there is this real acceleration force.
Since the car accelerates to the left (in the above diagram), the fake force is to the right and keeps the car in wheelie up position.
But what about torque? If you want to rotate an object, you need torque. One expression for torque would be (this is just the scalar form—for simplicity):
In this expression, F is the force, r is the distance from the point of rotation to the point where the force is applied and θ is the angle between these two things. For the total torque about the wheel, it’s really just the torque due to the gravitational force and the torque due to the fake force.
If you put the engine in the front of the car (where it usually is) then the center of mass moves closer to the front. This means the gravitational torque will be much larger (since r is larger). If you get the center of mass closer to the back wheel, the torque from the fake force doesn’t need to be as high to get a wheelie. Read the rest of this entry »
Wireless giant gets ad technology for mobile video; AOL Chief Tim Armstrong to remain
Mike Shields And Thomas Gryta report: Verizon Communications Inc. agreed to buy AOL Inc. in a $4.4 billion deal aimed at advancing the telecom giant’s growth ambitions in mobile video and advertising.
“Certainly the subscription business and the content businesses are very noteworthy. For us, the principal interest was around the ad tech platform.”
— Verizon’s president of operations, John Stratton,
The all-cash deal values AOL at $50 a share, a 23% premium over the company’s three-month volume-weighted average price. AOL shares rose 18% in morning trading to $50.18. Verizon shares fell 1.7% to $48.98.
The acquisition would give Verizon, which has set its sights on entering the crowded online video marketplace, access to advanced technology AOL has developed for selling ads and delivering high-quality Web video.
“Certainly the subscription business and the content businesses are very noteworthy. For us, the principal interest was around the ad tech platform,” said Verizon’s president of operations, John Stratton, at a Jefferies investor conference early Tuesday.
The U.S. wireless business has matured in recent years, leaving carriers like Verizon, AT&T Inc. and Sprint Corp. increasingly fighting to steal market share from one another. Offering digital video-over-wireless connections represents a growth avenue in coming years for Verizon, which last year brought in $127 billion in revenue and profit of $12 billion. Read the rest of this entry »
[Also see – Japan Makes First Arrest Over 3-D Printer Guns – punditfromanotherplanet.com]
Yoshitomo Imura, an employee at the Shonan Institute of Technology in Japan, was arrested last may for printing and firing a 3D-printed gun called the ZigZag. He printed three guns in total and was arrested for running afoul of Japan’s strict gun laws.
[More – [VIDEO] How 3-D Printed Guns Evolved Into Serious Weapons in Just One Year – punditfromanotherplanet.com]
For TechCrunch, Darrell Etherington reports: Twitter has just announced that it has formally joined the cause of those defending use of its service in Turkey, by filing petitions for lawsuits in a number of Turkish courts after working with its Turkish attorney over the course of the past few days. The petitions ask that the ban be lifted formally, and join the existing chorus of Turkish legal community members, citizens and journalists who have already succeeded in winning a stay of the Turkish government’s application to block the service entirely.
Twitter says that the proposed ban is a series of three court orders that it wasn’t privy to before the ban was enacted, which include two that the company claims relate to content on their network that violate their own terms of service, and have accordingly been removed. The last one, which deals with a tweet accusing a former minister of corruption, isn’t in violation of Twitter’s ToS, so the social network is petitioning the courts to overturn that remaining order.
You started out simple, piercing the dark with a cheap handheld flashlight as you traced a terrible rendition of your name through the air. You were hardly halfway through the last letter of your name before you were running over to the camera to see if it worked. You, like many a bored digital camera owner before you, had discovered light painting.
As its name implies, Pixelstick is… a stick of pixels
More specifically, the Pixelstick is a 6’ bar containing 198 full color LEDs. At the core of Pixelstick is a simple brain: a handheld controller, an SD card reader, and a bit of lightweight circuitry to parse images pulled from the card.
Not even the coolest president ever can conjure up a national medical regime for 300 million people
“We were working in a very very nimble hyper-consumer-focused way,” explained Todd Park, the chief technology officer of the U.S. Department of Health and Human Services, “all fused in this kind of maelstrom of pizza, Mountain Dew, and all-nighters . . . and, you know, idealism. That kind of led to the magic that was produced.” Read the rest of this entry »
To Get Around US Law, The NSA Collects Email Address Books And Chat Buddy Lists From Foreign LocationsPosted: October 15, 2013
The Washington Post broke news this afternoon that the National Security Agency (NSA) is collecting huge numbers of email address books and chat buddy lists for both foreign individuals and United States citizens.
It appears that the NSA lacks Congressional authority to collect buddy lists and address book information in the way that it currently does. As the Post rightly points out, address book data can include physical addresses, very personal information, and more.
To get around that lack of a mandate, the NSA has agreements with non-U.S. telcos and works with other, non-U.S. intelligence groups. So to get its hands on even more information, the NSA avoids the constraints of its provided oversight and legal boundaries, by going to alternative sources of the data that it wants.
That matters because the rules of other countries for tracking the communication of United States citizens are more lax. Recall that the NSA is in some ways slowed from collecting information on citizens of the United States, but not those of other countries.
So, if the NSA is willing to accept data from foreign intelligence agencies that it is not able to collect in this case, why not in other cases as well?
Here’s a video of Woojer’s Naimer pitching the concept earlier this year:
Natasha Lomas reports: Woojer is a wearable mobile accessory designed to allow its wearer to feel what they’re listening to on their mobile device — via the medium of haptic feedback — rather than simply having banging tunes inserted into their earholes. It’s also being aimed at gamers who want a more immersive in-game experience, or for watching movies or other audiovisual content on a mobile device.
The Israel-based startup behind Woojer, which closed a $600,000 angel round earlier this year, has been developing the product since the start of 2011. It currently has a working prototype — and plans to launch a Kickstarter campaign next month to raise funding for an initial production run. If that’s successful, they hope to ship to backers in early Spring 2014.
How exactly does Woojer work? Its creators describe it as a “tactile transducer” that reproduces sound as a polyphonic vibration, allowing a haptic, noiseless element to augment the standard stereo audio the user hears via their own headphones (which plug into the Woojer box via a 3.5mm headphone jack).
Unlike some of the rival offerings in this space, such as subpac and bassAware Holster, Woojer doesn’t require the user to strap on some form of backpack or wear a special headset. (Or look like they buy all their clothes at Cyberdog.) Instead, the roughly matchbox-sized box is clipped to clothing so it rests against the body. Its low frequency vibrations then create a physical bass sensation — similar to hearing live music at a concert or cinema surround sound. Or that’s the theory. Read the rest of this entry »
MATTHEW PANZARINO reports: Apple will hold an invitation-only event on October 22nd to show off its new iPads, as well as the new Mac Pro and OS X Mavericks release, according to areport from All Things D’s John Paczkowski.
That timing seems just right for the new iPads to make an appearance — last year’s event was held on October 23rd — and Apple has previously slated OS X Mavericks for a ‘fall’ release. It also makes some sense for Apple to talk about the Mac pro, also slated for fall, and to hopefully deliver us a release date. Read the rest of this entry »
If you like DVDs but also like shelf space, have we got a project for you. Called Jack the Ripper, this Raspberry Pi-powered system takes DVDs from one pile, drops them into a DVD drive for ripping, and then tugs them out and onto another spindle. Ad infinitum. Read the rest of this entry »
As Apple enthusiasts worldwide gear up for an imminent release of the new iPhone, Apple wants to make sure that Russian citizens don’t miss out.
Apple has sent some of its top executives “to meet with key distributors to revisit how it sells devices” in Russia. TechCrunch reports that Russia has experienced a short supply of iPhones, challenges working with carriers and had a grey market in the past. Hopefully these talks will result in better availability and easier access to iPhones for Russian consumers.
TechCrunch reports that Svyaznoy, a key distributor in Russia, sells half the iPhones sold in Russia in its 3,300 stores. Other distributors of mobile phones may never get iPhones to sell or face high subsidy costs. A July article on AppleInsider reported that three Russian carriers dropped the iPhone due to marketing costs and subsidies.
As Ingrid Lunden of TechCrunch notes, if Apple launches a lower-cost iPhone, it “has a shot of killing two birds with one stone in emerging markets … Apple can use it as an opportunity to finally give consumers there the supply that it has been demanding … finally bring more users into the fold.”