They are very good. 10 hours of solid combat is a fair price, as one rarely use it by itself, but accompanied as a knockout weapon, the 10 hours will last very long.
You cannot alch a Dungeoneering item.
g2h stands for "Gravite 2-handed sword" This is the strongest hitting melee weapon in free to play Runescape. It is a reward from the Dungeoneering skill.
If by Gravity Shortbow you mean the Gravite Shortbow, it's a reward bought from the Reward trader for 40,000 Dungeoneering tokens outside of Dungeoneering. It can't be brought into the dungeons and isn't an item in the dungeons.
You need 40,000 Dungeoneering tokens, so you need to get about 400,000 Dungeoneering experience. I couldn't find any reference on how much experience you typically get per hour, and I don't have enough experience myself yet.
Gravite shortbow.
a gravite weapon looses one charge every six minutes of combat.
The corrupt Dragon 2h is best tradable weapon on F2p, although is degrades rather fast. The Gravite 2h is not purchasable with gold, rather Dungeoneering tokens, and also degrades, but is the best weapon in Free-to-play.
hi, for melee, gravite 2h sword, for range, maple longbow (sighted) and for magic, gravite staff. All these items need a decent dungeonering level, but its worth it for the best weps!. hope this helped.
maple longbow sighted has a +110 and the gravite short has i think +47. If you want more accuracy choose the longbow sighted, but if you want faster speed choose the gravite shortbow. keep in mind that the longbow sight costs 10k tokens while the gravite shortbow costs 40k tokens and the gravite shortbow you have to keep repairing it, from 0% to 100% charged it costs 1 million GP. The longbow sight doesnt need repairing you buy it once and it's yours unless you lose it, you will have to buy a new one.
gravite
The overall best f2p Runescape weapon is actually a range weapon - Maple Longbow (sighted). It has a range bonus of over 100. The best f2p degradeable weapon is the Gravite 2h. Both are Dungeonneering weapons and need 45 Dungeonneering levels.
The best melee weapon for non-members is probably the Gravite Rapier, in terms of damage per second. The weapon with the highest accuracy and strength for nonmembers is the Gravite 2h sword, though this weapon attacks much slower. Please note that both of these weapons require you to dungeoneer for quite a while, especially if your combat level is 90 or higher.