Physics intensity question

Question

From a distance of 4.0 m, a bystander listens to a jackhammer breaking concrete. How far would he need to move from the jackhammer so that its perceived loudness decreases by a factor of 8?

Answer 1

Hello Michelle,

Intensity is Proportional to 1/d²

I = K/d²

Let I₀ = intensity at 4 m

I₀ = K/4² = K/16 Gives K = 16I₀

Decreased by a factor of 8

I₀/ 8 = K/d²

We need to find new distance d

I₀ = 8 K/d²

Plug in K

I₀ = 8*16*I₀ /d²

Gives d² =8 *16 = 128

d= 11.3m