We already said that the value of g is 9.81(m/s)/s. That's an accelaration value. Say that an object falls for 10 sec before touching ground, then it's speed will be (if we neglect air friction which in this case I think would be neglectible anyway) 98.1 m/s. If you consider the acceleration formula which is a= dv/dt ("d" standing for delta or variation)you'll get an acceleration of -98.1(m/s)/s if you slow down your object in one second. That is 10 times earth's g or 10G. Now it's easy to get a much more important g force on an object. Imagine you let your coffee mug fall for one second, it will get to a speed of 9.81m/s. If at the end of that second, concreet floor awaits, it will only take a fraction of second before it's stoped, say 1/10 of a second (probably conservative). Then again your poor little mug will endure 10g's... and will be blown to bits! -----Original Message----- From: Brian Ellis [mailto:[log in to unmask]] Sent: Thursday, October 11, 2001 2:08 AM To: [log in to unmask] Subject: Re: [TN] Question for the physics "gurus" Ken I'm damned sure that the black orange box may fall with an acceleration of 1 g, up to when air resistance starts to slow it down, but if it lands on a concrete road, it will decelerate at a very high value of g, depending on the give in the concrete and the box itself. It's all a matter of kinetic energy which is dissipated quasi-instantaneously. The g-value would be lower if it landed on somebody's head, because the latter being squashed down to the mid-torso would allow the acquired energy from the free fall to be better dissipated. No mental energy would be dissipated in such a case as the skull contents would be heated to dissociation of the grey matter molecules into other carbon and hydrogen combinations. Brian Ken Patel wrote: > > All, > If G force is the gravitation force acting on the object then why many times an object is > being designed to take so may G forces. What I have heard that voice recorder of the plane > that went down in Pennsylvania can take on 700G force! So, if the free fall is 1 G then why > design 700 times safer. So, height above the ground does matter. May be I got to take a look > at the physic's book unless someone explain in layman's term. > > re, > Ken Patel > > Timothy Reeves wrote: > > > No Jason, > > I am not a guru, but that's OK. They are not interconvertible. One is a > > measure of force, the other acceleration (actually a dimensionless > > multiplier of the standard gravitational acceleration, g, 9.8 m/s^2). If you > > have an object in mind of a known mass, you could find the force exerted on > > it given the acceleration ("G's") by F = m a. > > > > Example: 100 gram object subjected to 5 G's ---------> F = 0.1 kg * 5 * 9.8 > > m/s^2 = 4.9 Newtons or 0.5 kilogram force or 1.1 lb-force. > > > > Tim Reeves > > > > -----Original Message----- > > From: Jason Gregory [mailto:[log in to unmask]] > > Sent: Tuesday, October 09, 2001 9:01 AM > > Subject: Question for the physics "gurus" > > > > How do you convert pound/kilogram to G-force? Is this convertable? Since > > G-force is somewhat time derived and pound/kilogram is force derived? > > Any help is appreciated. > > > > Jason Gregory > > Software Specialist - NPI Group > > SCI Systems/Plant 2 > > 13000 S. 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