If you missed today's class in 2013-2014 (any of the teachers classes)
Watch this video to see students making your measurements
Then watch this video to see their data and I explain briefly what to do with the data.
Finally, here is the smart board work done by other periods with different data than period 8 that may help you finish your lab. period 3 period 7
If you missed today's class in 2012-2013
We demonstrated how bulletproof vest absorb the energy of impact by letting students hit us in the stomach while wearing a bulletproof vest. We pasted around a pair of bulletproof vests and a small box with a section of a bullet proof vest so students could feel the kevar fibers and three bullets that had been shot into a bullet proof vests. We also had an egg cartoon with several bullet casings and the bullet outside the casing above it in the egg carton with statics about each bullet written on the inside lid.
Watch the following short video explaining how bulletproof vest works.
We also continued working on the homework sheet
Videos showing how bullet proof vest absorb the energy of a punch
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Finally we gave time for lab partners to finish up yesterdays lab.
The BIG PICTURES for today is:
1. Bulletproof vest are NOT Bulletproof but bullet resistant as they catch the bullet thus prevent the bullet from entering your body. Even though the energy of the impact is spread throughout the vest the impact site leaves a huge bruise and possibly broken ribs (still better than the alternative).
2. Homework problem 13 allowed you review momentum and relate it to the conservation of energy. Some problems the work done equaled the K.E. (if solving for velocity) and others the work done equaled the P.E. (if solving for the height).
1. Bulletproof vest are NOT Bulletproof but bullet resistant as they catch the bullet thus prevent the bullet from entering your body. Even though the energy of the impact is spread throughout the vest the impact site leaves a huge bruise and possibly broken ribs (still better than the alternative).
2. Homework problem 13 allowed you review momentum and relate it to the conservation of energy. Some problems the work done equaled the K.E. (if solving for velocity) and others the work done equaled the P.E. (if solving for the height).