I have been out of school for a few years so my physics is rusty. I need help figuring something out for my job. I need to know how high I must drop an object so that it hits the ground with an impact of 1000g's. The object is a cylindar and weighs 2lbs. I have been confusing myself. I know that the object will fall with 1g acceleration. I think need an equation that allows me to find the instantaneous acceleration at the moment of impact. I think I can assume an infinitely hard ground for now. I have found that instantaneous acceleration is delta v/delta t where t->0. ~~~~ If a=9806 m/s^2 then as t-->0, the velocity would be 9806 m/s? So then I think I need to use another equation to back out the height I found this equation for free-fall with no air resistance but I'm not sure it helps. y(t)=-1/2*g*t^2 + v_o*t + y_o I found this equation for impact vel just before impact = sqrt(2*g*h). But if I set it equal to 9806 I get h=4,903,000 meters...that seems very high. I am also worried when the equations don't take mass into account. ~~~~~ Another option I thought of: F=ma F=(.907 kg*9806m/s^2) F=8894N And then I would need some sort of equation that lets me back height out of newtons. Can anyone help me? I'm going in circles.