Sign up for our daily briefing

Make your busy days simpler with Axios AM/PM. Catch up on what's new and why it matters in just 5 minutes.

Please enter a valid email.

Please enter a valid email.

Subscription failed
Thank you for subscribing!

Catch up on coronavirus stories and special reports, curated by Mike Allen everyday

Catch up on coronavirus stories and special reports, curated by Mike Allen everyday

Please enter a valid email.

Please enter a valid email.

Subscription failed
Thank you for subscribing!

Denver news in your inbox

Catch up on the most important stories affecting your hometown with Axios Denver

Please enter a valid email.

Please enter a valid email.

Subscription failed
Thank you for subscribing!

Des Moines news in your inbox

Catch up on the most important stories affecting your hometown with Axios Des Moines

Please enter a valid email.

Please enter a valid email.

Subscription failed
Thank you for subscribing!

Minneapolis-St. Paul news in your inbox

Catch up on the most important stories affecting your hometown with Axios Twin Cities

Please enter a valid email.

Please enter a valid email.

Subscription failed
Thank you for subscribing!

Tampa Bay news in your inbox

Catch up on the most important stories affecting your hometown with Axios Tampa Bay

Please enter a valid email.

Please enter a valid email.

Subscription failed
Thank you for subscribing!

Charlotte news in your inbox

Catch up on the most important stories affecting your hometown with Axios Charlotte

Please enter a valid email.

Please enter a valid email.

Subscription failed
Thank you for subscribing!

Please enter a valid email.

Please enter a valid email.

Subscription failed
Thank you for subscribing!

Associated Press

Scientists in Paris have figured out what causes rolling suitcases to wobble then overturn. Their counterintuitive solution to the problem: speed up.

How it happens: Physicists studied suitcase instability by creating a model of a two-wheeled suitcase rolling on a treadmill. They found that a suitcase unsurprisingly begins to rock when it hits a small bump or something knocks into it. When one wheel is lifted off the ground, the tilted suitcase shifts to realign the wheels but when the wheel hits the ground again, the other one lifts and the energy from movement is transferred, rocking the suitcase the other direction. The motion continues or the suitcase falls over so long as the energy from rocking is greater than the dampening that occurs when the wheel touches the ground again.

How to make it stop: Go faster. It won't stop the oscillations entirely but it will decrease the amount of energy transferred from pulling to rocking. "Thus, one should rather accelerate than decelerate to attenuate the amplitude of oscillations. A non-experienced suitcase puller would not react this way," the authors wrote.

What's new: "People used to assume it was a resonance and that when you are walking, tiny movements in your hands are transferred to the suitcase and amplified," says Paris Diderot University physicist Sylvain Courrech du Pont. "By we, I mean the one guy who studied this."

Beyond suitcases: The rocking motion could inform the design of towed trailers, especially autonomous ones that will need to know how to self-correct the movement.

Go deeper

Tech scrambles to derail inauguration threats

Illustration: Sarah Grillo/Axios

Tech companies are sharing more information with law enforcement in a frantic effort to prevent violence around the inauguration, after the government was caught flat-footed by the Capitol siege.

Between the lines: Tech knows it will be held accountable for any further violence that turns out to have been planned online if it doesn't act to stop it.

Dave Lawler, author of World
5 hours ago - World

Uganda's election: Museveni declared winner, Wine claims fraud

Wine rejected the official results of the election. Photo: Sumy Sadruni/AFP via Getty

Yoweri Museveni was declared the winner of a sixth presidential term on Saturday, with official results giving him 59% to 35% for Bobi Wine, the singer-turned-opposition leader.

Why it matters: This announcement was predictable, as the election was neither free nor fair and Museveni had no intention of surrendering power after 35 years. But Wine — who posed a strong challenged to Museveni, particularly in urban areas, and was beaten and arrested during the campaign — has said he will present evidence of fraud. The big question is whether he will mobilize mass resistance in the streets.

Off the Rails

Episode 1: A premeditated lie lit the fire

Photo illustration: Sarah Grillo/Axios. Photo: Chip Somodevilla/Getty Images

Beginning on election night 2020 and continuing through his final days in office, Donald Trump unraveled and dragged America with him, to the point that his followers sacked the U.S. Capitol with two weeks left in his term. Axios takes you inside the collapse of a president with a special series.

Episode 1: Trump’s refusal to believe the election results was premeditated. He had heard about the “red mirage” — the likelihood that early vote counts would tip more Republican than the final tallies — and he decided to exploit it.

"Jared, you call the Murdochs! Jason, you call Sammon and Hemmer!”