Mobile suits

Mobile weapons (機動兵器, kidō heiki^?) are fictional weapon systems from the Gundam anime metaseries. The term originally includes all self-propelled military used vehicles including traditional tanks and aircraft. However, the English term was used to generalize all weapons including mobile suits, mobile armour and any other machines based on the same mecha technologies. Note that in Universal Century, most weapons are designed to combat under the influence of the Minovsky Particle and thus differ from conventional weapons.

Although mobile suits are the main focus of the series, tanks are in use. For example, in the One Year War, Earth Federation Ground Forces rely heavily on their Type 61 Tank since they do not have mobile suits until towards the end of the war. Zeon forces also introduce a tank/fighter hybrid, the Magella Attack Tank, as mass-produced ground vehicles helping the outnumbered Zeon mobile suits against the Earth Federation's massive force of Type 61s.

In the background story, more is told about tanks and readers could conclude that tanks are actually still the main ground combat unit, mobile suits are comparatively less effective due to their complicated designs and size. Tanks are less seen on screen just because the series focuses on the development of mobile suits.

The Type 61 can hardly be imagined as a mobile weapon using the same technology as MS and MA since it is manufactured in UC0061, well before the Minovsky Technology become mainstream. However, the Magella Attack incorporates propulsion technology of the mobile suits and can have a thrust large enough to lift it in air while firing its cannon.

Later in the story, the Earth Federation Forces deployed a tank called G-Bull as a support mecha of RX-78-2 Gundam and have E-Cap technology built in for it to fire beam weaponry.

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Wikipedia