[clueless (OP)]

I have a question about friction and acceleration. Imagine a wooden surface, or made in stone (I’m not sure yet), inclined for, say, 40 degrees. I guess you could slide down, right? So since you accelerate as you slide down the incline, will you be badly hurt or even die when you arrive at the flat earth? I need a scenario when you safely slide down for about 10 seconds (w/o getting hurt or you do receive minor injuries). Thanks.

[alancalverd]

A quick look at a children's playground suggests this isn't a problem.

[clueless (OP)]

Err... you're right. I'm clueless. 

[RD]

A quick look at a children's playground suggests this isn't a problem.

What about sliding down a newly-made Egyptian pyramid ? ... http://www.todayifoundout.com/index.php/2011/04/the-pyramids-of-giza-were-originally-white/

If the friction was not sufficient to slow your descent you'd slam into the desert at high speed.
If the friction was higher it could strip the flesh from your body by the time you got to the bottom.

[clueless (OP)]

...and I thought I was morbid.   

[alancalverd]

If the friction was not sufficient to slow your descent you'd slam into the desert at high speed.
If the friction was higher it could strip the flesh from your body by the time you got to the bottom.

(a) that's why they make slides from polished wood or metal, not stone, and

(b) if the friction was sufficient to strip your skin, you wouldn't begin to slide in the first place.  That's why you don't slide downhill if you sit on a roadway. More to the point, that's how cars drive uphill. If you lock the brakes when the car is moving quickly, road friction will indeed remove the rubber from the tyres even on a horizontal surface, but if you lock the brakes when it is not moving, it won't slide on a 1 in 2 slope.

[CliffordK]

I usually don't strip down nude before jumping on a slide made of sand paper.  []

Rocks can be polished smooth by both natural and artificial means, or left rough. 

I've been down a natural rock slide down a creek bed, and landing in a pool of water below.  It was fun.

I would wonder how quickly one would reach terminal velocity when going down a slide.  I presume it takes fine tuning to get the slide to have enough angle that one slides, and not too much that one is killed at the bottom. 

However, most slides also change the slope at the bottom, so the kids slow down somewhat at the bottom, perhaps even coming to a stop rather than getting slammed into the ground.

Sliding down a steep grassy or sandy hillside can be fun if there are no obstructions, and the slope becomes gentle at the bottom, or it can be downright scary if there are many things to bump into, a rough rocky surface and potentially a cliff at the bottom.

[RD]

I usually don't strip down nude before jumping on a slide made of sand paper.  []

Regular clothing doesn't provide much protection ... 

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[CliffordK]

Good film.  But, the denim didn't do too bad, with a bit of scuffing on the pockets (I suppose one shouldn't choose a pair of jeans with the knees already worn out).

If the mannequin just had a good wallet in its pocket, it might have ended up a little poorer, but otherwise no worse for the wear. 

What about motorcycle leathers?