Transcript: Calculate minimum distance for first aid tent fill in the blanks

Remember: SPL₂ = SPL₁ minus 20 times log times (R₁ over R₂)

where R is the distance in metres from the source of the sound and SPL is the sound level in decibels at that distance.

Question

Use the formula to determine how far away the first aid tent will need to be (R₂) for a sound level (SPL₂) of 60 decibels.

How far away should James set up the first aid tent?

Hint

This time we’re solving for R₂. Again, we’ll begin by filling in the values that we know:

60 = 100 minus 20 times log times (R₂ over 1)

We can simplify this as follows:

negative 40 = negative 20 times log times (R₂)

2 = log times (R₂)

To solve this, we’ll need to rewrite it as an exponential equation. Remember that when no base is written, we are working with the common log, which is base 10.

10 squared = R₂

R₂ = 100 metres

Answer

James will need to set up the first aid tent 100 metres from the stage.