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In this article (see the for this possibility at the end of the article) you can play around with various quantities related to a black hole. If you make the mass of the hole very large, the acceleration at the event horizon becomes very small compared to that of the earth. So why then is it so difficult to accelerate an object very near to the event horizon and make it move away from the hole? Is it because of the difference between the coordinate time $dt$ as measured by a far away observer, which makes the acceleration have such a small value, and the proper time $d\tau$ for the mass very near to the event horizon (which makes the time almost stop)?

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Deschele Schilder
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If you were to hover at a distance $r$ from a black hole of mass $M$ then the acceleration you would feel is given by:

$$ a = \frac{GM}{r^2}\frac{1}{\sqrt{1-\frac{2GM}{c^2r}}} = \frac{GM}{r^2}\frac{1}{\sqrt{1-\frac{r_s}{r}}} $$

This is derived in twistor59's answer to What is the weight equation through general relativity?

At $r = r_s$ the acceleration goes to infinity regardless of the mass of the black hole, so for all black holes the "g forces" you feel at the horizon are infinite.

The article you link is talking about Hawking radiation, and Hawking radiation is proportional to a property called the surface gravity, $\kappa$, at the horizon. The surface gravity is the acceleration calculated above multiplied by the time dilation factor. This is discussed in my answer to Why do larger black holes emit less Hawking Radiation than smaller black holes? The surface gravity is given by:

$$ \kappa = \frac{1}{2r_s} $$

so it does decrease as the mass of the black hole increases. The surface gravity is, in a rather handwaving way, the local acceleration at the horizon measured by an observer at infinity. It is relevant here because the Hawking radiation is measured at infinity as well.

So you are basically correct that it is the time dilation that causes the surface gravity to fall as the black hole size increases. However this is not the local acceleration experienced by an observer trying to escape the black hole so it does not mean objects can escape from a large black hole.

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John Rennie
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Only a small amount of momentum is exchanged between the very large black hole and the thing hanging near that black hole in one second of high altitude clock's time.

But as the thing hanging near the event horizon is very time dilated, in one second of the things proper time there are many seconds of high altitude clock's time. So if we ask the thing, there is a large amount of momentum exchanged in one second of its time. Another way to say that is that there is a large force.

stuffu
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