The NFL divisional playoffs are all about physics. Will the objects in motion (the four teams that won road games in the wild-card round) also deliver against objects at rest (the four highest seeds that had byes last week)?

The degree of difficulty is raised to win two in a row on the road, especially when a team just played and got more banged up. But one is built best to maintain its momentum.

MORE: David Steele’s picks | Betting lines | SN’s 2015 NFL awards

Wild-card playoffs straight-up record: 4-0

Wild-card playoffs against the spread record: 2-2

Season-to-date straight-up record: 166-94

Season-to-date ATS record: 131-123-6

Line: New England -5

Saturday, 4:35 p.m. ET, CBS

This isn’t the same Kansas City defense that throttled New England on a Monday night last season, a game that had everyone doubting whether Tom Brady had anything left. It’s actually a better defense. The Chiefs still can stop the run and rush the passer, but now they have another big-play cover man in Marcus Peters. Justin Houston and Tamba Hali should be licking their chops to go after an injury-riddled Patriots offensive line.

But Brady is also better a year later, and his supporting cast, including Julian Edelman, Danny Amendola and Rob Gronkowski, are all healthier. He will find one or two good matchups to move and protect the ball, not worrying about how effectively the Patriots can run the ball.

Really, it’s the Patriots defense that saves the day. Alex Smith is set to be without top wide receiver Jeremy Maclin, and with New England set to get back its key players in the back seven, the Patriots should take full advantage. Smith won’t be able to match Brady’s efficiency on the road, and the Patriots survive with a big takeaway late.

Patriots win 20-16 but fail to cover the spread.

MORE: Playoff predictions: Familiar road for Pats?

Line: Arizona -7

Saturday, 8:15 p.m. ET, NBC

When these teams met in Week 16, it wasn’t close — a Cardinals 38-8 rout, during which the Packers dried out in the desert. It allowed Aaron Rodgers to take a beating with eight sacks before he left a lopsided game. The Packers figured out some fixes in pass protection in Washington to make Rodgers look like Rodgers, but Arizona’s aggressive attack scheme, backed by a still deep man-to-man secondary without Tyrann Mathieu, is a different story.

Rodgers should play a lot better, as the Packers will be wise to take some pressure off him early to call for many runs and quick passes. But it will be hard for him to light it up enough. That’s because the Packers will give up some big runs to David Johnson and long passes to Carson Palmer, who will pick Green Bay’s poison with his wide receivers. The Cardinals are the better all-around team in every way, and they prove it again.

Cardinals win 30-20 and cover the spread.

STEELE: Rodgers is still Rodgers, and Packers like that

Line: Carolina -3

Sunday, 1:05 p.m. ET, FOX

The first matchup was a thriller, with the Panthers rallying with 14 points in the fourth quarter to take the game 27-23 in Seattle. Outside of this rematch being played in Charlotte, there are a few key differences.

The foremost is the Seahawks throwing the ball more effectively to their wide receivers, as Russell Wilson has been locked in throwing everywhere downfield for the past couple months. On the flip side, the Panthers’ secondary has been weakened by injury away from shutdown cornerback Josh Norman.

The Seahawks’ secondary, meanwhile, has gotten better at corner with Jeremy Lane. At middle linebacker, Bobby Wagner, who missed the first game, is dominating. Both teams will struggle to run the ball, given Luke Kuechly is also cleaning up as the Carolina counterpart.

So it comes down to which QB — Wilson or Cam Newton — can escape the pressure and get support from playmakers. Seattle should key on containing tight end Greg Olsen, so the Panthers’ wideout limitations will catch up with them against The Legion of Boom. It’s either Doug Baldwin, Tyler Lockett or Jermaine Kearse who comes up with the final big play to help Wilson and the Seahawks advance to another NFC title game.

Seahawks win 27-26 in an upset.

MORE: Panthers know Seahawks matchup was inevitable

Line: Denver -7

Sunday, 4:40 p.m. ET, NBC

Ben Roethlisberger will fight through his shoulder injury and play. But even when healthy this season, he has struggled against good defenses on the road. He’ll also be down two key players, running back DeAngelo Williams and (probably) go-to wide receiver Antonio Brown.

Brown ripped through the Broncos’ tough coverage and was the reason the Steelers rallied to win the first matchup in Pittsburgh. The Steelers suddenly go from 60 to zero with their offensive explosiveness, as Markus Wheaton and Martavis Bryant can’t get the job done against the Broncos’ brutal cornerbacks. Big Ben will have his hands full with the heat of Von Miller, too.

As for Peyton Manning, his main goal is to get out the ball quickly to his deeper, healthier supporting cast and simply avoid turnovers. The Broncos’ defense will do most of the winning here, and Manning will do his job as effectively as they need.

Broncos win 26-10 and cover the spread.

GENTILLE: Of course Big Ben will play in Denver