$30$ seconds of exposure to $115$ dB sound can damage your hearingm but a much quieter $94$ dB may begin to cause damage after $1$ hour of continuous exposure. You are going to an outdoor concert, and youll be standing near a speaker that emits $50$ W of acoustic power as a spherical wave. What minimum distance should you be from the speaker to keep the sound intensity level below $94$ dB$?$