My daugther’s growing up from toddler to small kid is happening without me. 🙁 And all I get the stories. She has a bump on her head, slightly bruised near the ear and a red swelling nose. My wife told be she fell down the stairs.
These stories really make me uneasy. And I found out she feel from the second to the last step and went down head forward, since her bump is in the middle of her forehead.
While chatting with my Marcia, my wife… I was doing a few rough estimates. Since she fell head first dropping like a log into a slightly diving position, and her feet was like stationary, it was her head that was building up acceleration. I estimated that to be about 3 feet which is 0.9144 meters. And acceleration due to gravity is 9.8m/s2, that means based on my estimate, her head was travelling at 8.96m/s2.
Force is mass multiplied by acceleration. And Marcia said Jamie is 10kg. The head is less than 25% of the total body weight. So I estimate it to be 2kg. That makes the force of impact 89.6 Newtons. And since I rarely use newtons in my life, I can’t even imagine it. I have no reference of how that feels like.
But in contact sports, punches are sometimes measured in pressure with the unit pounds per square inch. Often used in tires which is called PSI. And in sports they simply refer it as pounds. Pressure is force per unit area, and the area is the bump on her head which I estimate to have a 1×1 inch area. But I need metric to used the area with the Newton unit and the pressure is 3527.56kg/m2. Converting that to PSI is 5.02lbs/in2. Ouch! Now I can imagine it more. Having a few references based on experience… a 10 pound bowling ball, and getting half of that, laying on the floor, and having it fall on my head at 3 feet. Ouch.
Poor Jamie, good thing she is still a kid. Things like that are not nice to happen when you are grown up and falls like these also serve as balance lessons as they grow up. I guess everyone of us has a memorable bump on their head as a kid. I have tons of them until college days, mainly form the sports I was into. No wonder I am crazy. 😛
Jamie, take care next time. Daddy gets worried being far away. See you all soon Ate and Mommy too.