G force question

1. May 16, 2007

Markus78

Hello,

Im trying to calculate the amount of G force generated from a golfswing for example. Let's say the swing is carried out with an acceleration of 26rad/sec, and that it is perfectly circular ;)

Im using formula a = w^2 *r; If my armls add 40cm and I want to know the G force 6cm below my grip...

a = 26^2 * 0.23 = about 155, divided into 9.82 meters/sec = 16G ,

That sounds a bit high to me so I would like to know if I am doing something wrong here...

Br
/Markus

2. May 16, 2007

FredGarvin

From what you have given, the only thing I see wrong is that you used your arm distance plus 6 cm as a diameter and not a radius. I assume that you are considering your shoulder as the center of the circle.

Your angular velocity (not acceleration) of 26 rad/sec is moving pretty quickly. It's almost 250 rpm.

3. May 16, 2007

Markus78

Aa that's right, so the correct value should be more something like 26^2*0.46 then... that's more like 30G,

I got the value 26rad/sec from some golfing website, it might be wrong, but the pro's can reach a speed of 100mph at the tip of the club, not sure how to convert that into rad/sec though.

/Markus

4. May 16, 2007

FredGarvin

It wouldn't be to tough to do an experiment to see how good your numbers are. A spring scale and a weight to mimic the club would do it.

30 G sounds a bit high, but not totally unreasonable.

5. May 16, 2007

AlephZero

100 mph = 160 km/h = 160*1000/3600 m/s = 45 m/s

Angular velocity = v/r where r is the total radius (length of arm + club). From the size of a normal person, r must be a bit less than 2m, say 1.8m

Angular velocity = 45/1.8 = 25 rad/sec.