Replies

Let's say she reached a height of 6 feet, and rolled/slid for 12 feet -- leaving a distance of 60 feet in the air.

Using d = 1/2 a t², it would have taken her about 0.6 seconds to drop six feet. Total flight time would therefore have been about 1.2 seconds, meaning that her speed was something like 50 feet/second, or 34 mph.

If we assume a radius of 4 feet for the merry-go-round, the ejection speed of 50 feet/second corresponds to an angular rate of 12.5 radians/second, or about 120 rpm.

We have to assume, btw, that the dumbass kids wrapped the ropes around the outside handles of the merry-go-round.

24 yards is pretty good. Assuming a weight of 120 for the victim, I'd love to see somebody do the math on what the rotational speed of that thing was.

Her weight shouldn't come into play -- much like a bullet fired horizontially from a gun will land on the ground at the same time one is dropped from your hand.

So figure the truck is the bullet and the speed of the bullet (Vh) is how fast the truck was going before she let go. The only other variable to consider is consider how high (H) off the ground she was when she let go.

She has two components of motion: tangenial to the merry go around (Vh, Ah = 0 where A == acceleration) and toward mean old earth (Av = 9.8m/s^2).

H = Vv * t + 1/2 * Av * t^2 where t == seconds aloft.

Since she had no downward velocity (Vv) to start off with this simplifies to H = 4.9*t^2. If the H = 1.5 meters that means she was aloft for (1.5/4.9)^0.5 = 0.55 seconds.

How far does this travel? That's D = Vh * t.

Since we know the distance of 24 yards = 9.1 meters:

9.1 meters = Velocity * 0.55 seconds

Or the velocity is 16.5 meters / s = 37 MPH

For the merry go round the velocity at an outside point is V = radius * radians / second = radius * RPM * 2*pi / 60

Pluging in 37MPH = 54 feet / second = 2 * radius * (RPM) * pi / 60 = Diameter * RPM / 19.1

Figuring a typical merry go round diameter of 10 feet that works out to be 54 ft / second = 10 ft * (RPM) / 19.1
100 revolutions per minute.

Keep in mind its been 10 years since I did anything with Excel so I could of screwed up somewhere. But 37MPH sounds about right if you have enough rope wrapped around the merry go round. Also I'm not accounting for things like wind resistance and the flailing of the individual.