The students appear to be focused on the physics of feats performed primarily in movies and occasionally in the comic books. They looked at how much energy it would take to perform certain feats for superman and how much solar energy would be need to power it. They looked at the tissue density needed to resist bullets (standard hand gun bullets).
They looked at Thor but gave him an iron hammer instead of a magic Uru metal hammer. Wolverine got an osmium reinforced skeleton instead of adamantium.
Based upon the comic book movies and television shows, Nextbigfuture would put Professor X or Dr. Strange as the winners of a superhero showdown. Superman is vulnerable to psionic mind control and to magic. Psionic or magic illusions could be used to misdirect any attacks from superman until control could be established with mind control or magic.
Another point is that in a world where superpowers were real and hand gun bullet resistance and rapid tissue regeneration was a common factor then everyone would use more powerful weapons.
Typical Tank Armor is 18 to 30 inches.
Tony Stark (iron man) developed hulk-buster armor when he needed to deal with the Hulk. Clearly he would create superman buster armor(s). He has developed multiple drone armors. Bruce Wayne (batman) has also developed gear specifically to deal with super-powered foes.
The gear I will list below exists in reality for infantry to go up against armored vehicles and tanks. Tony Stark has about a 10-20 year or more technological lead over reality. He has a portable fusion reactor.
I think Tony would head toward Bolo AI tanks
The RPG-7 has made it the most widely used anti-armor weapon in the world. The insurgent fighters who have to deal with tanks and armored vehicles have a lot of RPGs (rocket propelled grenades). Similarly anyone going up against a superman or wolverine would up-weapon themselves.
The Barrett XM109 is a prototype anti-materiel rifle, chambered for 25 × 59 mm grenade rounds and developed by Barrett Firearms Manufacturing. It was designed in accordance with a requirement set out in 1994, and is capable of defeating light armor and equipment out to 2 km (1.2 mi). Tests indicated about 2 inches of armor penetration at 500 meters.
There is a list of infantry anti-armor weapons here
The Mark 47 is a newer fully automatic grenade launcher. It is much lighter than the Mark 19, weighing 39 pounds as opposed to 77. It also has a capacity for airburst rounds, and the antiarmor round is the same HEDP as the Mk 19, offering the same 2200m range and 50mm armor penetration.
The Javelin ATGM is a ground-breaking weapon and was first used in combat in 2003 at the Battle of Debecka Pass. US Special Forces and Kurdish Peshmerga guerrilla engaged a force of eight armoured personnel carriers and four T-55 tanks. At least four of the APCs were destroyed by Javelin missiles. The Javelin was the first man-portable fire and forget antitank weapon. It uses an imaging infrared seeker to track the selected target. The Command Launch Unit and missile tube weigh just under 40 pounds. The Javelin has a maximum effective range of approximately 2,000 meters.
The BGM-71 TOW is the heaviest antiarmor missile operated by ground forces in the US Army. It is always vehicle-mounted, and can be found on the Bradley, Stryker ATGM vehicle and selected uparmored Humvee. The more recent variant is the TOW-RF, which unlike older models is not wire-guided and so has its range boosted to 4,500 meters as a result, as opposed to the A through H models’ range of 3,750 meters.
SOURCES - University of Leicester, firearm blog, wikipedia