How long can you be exposed to 85dba without hearing protection?

What are examples of a first class pulleys? What will increase when you increase pitch angle rotor blades? How do currents flow round two series and parallel circuits? What is the meaming of rotary pumps? Self starting single phase induction motors are also called? Is it common for a plumber to install a shower pan and liner wrong? Why did they invent a chair? A pendulum of the length L is suspended from the ceiling of an elevetor. When the elevator is at rest the period of pendulum is T. What is the period of the pendulum if the elevator is freely falling? How do you change the size of a text box with CSS? Who invented the lasting machine? What are the most common voltage sources? What is the towing capacity of a 2003 Mercedes c class estate? Who is reliable sap support consultant for offshore sap development across US? What is the tag line of genpact? Is Yahoo a computer program? What is filter in rectifiers? Can you lay tile directly onto a rubber shower membrane? What is the best material of the core of a transformer? What is the difference between volumetric analysis and gravimetric analysis? What are the different shapes of science and technology?