Everybody loves a good hero. But, are they realistic? Some of our favorite crusaders - Batman, Link, Green Arrow - use grappling hooks to get around. I wonder if they’d work like in the games and movies.
Let’s say Batman is trying to get into Arkham Asylum to teach some no good-nicks what he thinks of this whole “rehabilitation” thing. He needs to get two floors up, which is about 6.6 m. And, like in the movies, he needs to rocket up that distance, let’s say at about 6 m/s. The average man weighs 70 kg, but Batman is pretty buff, so we’ll make it 75 kg. We can calculate the work needed to be (.5)mv^2 + mgh, which here equals 6205.95 J. We also know v = d/t, so that means t = d/v = 1.1 s. And, power = W/t = 5641.77 W.
It’s pretty safe to say a handheld motor like the ones we see in the media couldn’t make over 5.5 kW of pull. A mounted artillery grappling gun could, and are used by the US special forces for stealth missions. However, until our technology evolves a bit more, Batman will just have to learn to actually fly.