I will assume you are correct. Now David sit up straight and answer this for extra credit. A train leaves Nantucket traveling 60 mph and pulling 75 cars heading towards Pikeville. Another train leaves Pikeville traveling 45 mph and heading towards Nantucket. When they collide in Stratford showering the grain silos with steel shrapnel, what would be the correct shutter speed to use in order for the sleeping signalman to register clearly on film as he wakes up and flees the scene? Greg > -----Original Message----- > From: ADavidhazy [mailto:ANDPPH@ritvax.isc.rit.edu] > > > Assuming none of the cars stop and everyone flies through > the intersection at > > 30 mph, the image frame encompasses 1/2 block, what is the > minimum shutter > > speed needed to prevent the moving cars registering? > > Greg, you devil, > > Well, according to my postulated theory ... the fact it is > 1/2 block does not > make much difference ... what matters is the speed that cars > are moving at. > Assume a car is 15 feet long. At 30mph it is moving at about > 45 feet per > second. So it covers its own length in 1/3 second ... so 100 > times that is 30 > seconds. > > So, the answer is 30 seconds. > > am I right? > > andy > > >
