I have been using continuous lighting for mannequin pictures and it was quite difficult to overexpose the background all the time however I made it work. Due to my dog ( long story) I am being forced to upgrade sooner than planned. I was wondering if two 160 watt strobe lights would be enough to over expose a 5x10' background. I am not concerned with perfect lighting on the subject at the moment — I just want the background to be a solid white (some refer to it as "high key").
There are details... Flash is rated as watt seconds (electrical energy input). A continuous light is only useful for photography while the shutter is open. Watts is its rate of energy. A 250 watt continuous bulb through a one second shutter is 250x1 = 250 watt seconds, but at 1/100 second is 250x1/100 which is only 2.5 watt seconds. Huge difference.
The 160 watt second flash is 160 watt seconds at any shutter speed (up to camera maximum sync speed, typically around 1/200 second shutter)... 160 is another huge difference. And the flash is also maybe about 4 times more efficient than incandescent about making light from energy (efficiency about like fluorescent bulbs, instead of just making heat). So flash is a lot of light.
I'd say one flash does it, CERTAINLY AS COMPARED TO CONTINUOUS LIGHTS, but it depends on your exposure of course. A silly example would be that a flash metering f/5.6 will overexpose a f/4 exposure by one stop. 1/2 stop over should be enough to make a white background be very white (incident metering).
As an example of one case, the Paul C. Buff company (Alienbees, etc), publishes this chart: http://www.paulcbuff.com/output.php It says a 160 watt second Alienbees B400 flash with standard 7 inch reflector (80 degrees wide) has a Guide Number of 77, which is almost f/16 at 5 feet, ISO 100.