=Non interview technical questions= 

• How to measure speed of a tennis ball... by Merc_1976.
  During big tennis tournament there is a large score table reporting speed of a tennis ball. What type of sensors or radars do they use?
  
   
   
   
• Automatic control of a stage projector ... by Merc_1976.
  My neighbor plays bass guitar in a band. He told me that they had a light effects system that included a joystick to manually control projectors. There is an operator who's job is to focus the light spot on a singer while she moves around the stage. I have been thinking lately what would be the best way to automate that process. Any ideas?
  
   
   
  
   
   
• Applying black paint to a heat sink: better or worse?.. by Johan_son.
  Had an argument recently with a coworker from manufacturing dpt: they apply black paint to increase performance of a heat sink. I don't think it's a good idea, because paint provides thermo insulation. Am I right ?
  
   
   
   
• Phone for mute pepople?.. by Anonimous1.
  Is there a way to design a phone for mute people ?
   
   
   
• Better road grip with wider tires?.. by Victor.
  Most people agree that a car with wider tires has better road grip, but the theory doesn't seem to explain this? I remember from school that a force of friction depends on surface and weight and has no relation to the area:
  F = kN,
  where k - friction coefficient depending on material, N - is a normal fource proportional to the weight of a car.
  What am I missing?
   
   
   
• Measure multiple points... by Seviri.
  I Would like to get experts opinion on the following problem. I am taking voltage measurements at multiple points. The data is within 1v...2v range. Will I get better accuracy if I use the same instrument for all measurements rather than taking parallel measurements ?
   
   
  
   
   
• Question to power supply experts... by vball13.
  I need to build a test bench for a chip. The chip has a block that when enabled draws 1.6A from a supply during 5nS. The problem is I need to put 20 chips on the test board. Any suggestions?
   
   
   
• Granite ball in San Diego... by alex.
  Last month I took a trip to San Diego, CA. I stopped at the coffee shop downtown La Jolla.
  They have a small fountain right in front of that shop. Nothing unusual on the first sight. The fountain is in the form of a plate. There is a ball on that plate, and water comes from underneath the ball. When I came closer I noticed that the ball seems to be floating on that plate. It must have made from rubber...
  I touched it: no, the ball as well as the plate were made from granite. And again the ball was floating... I am an engineer myself. My best guess would be that the water pressure keeps that granite ball floating. Is it so, or is there another trick?
   
  
  
   
   
   
• 2 outlets in series? by A3.
  Hi, can I connect two 110v outlets in series to double the voltage?