1. A student standing near a brick wall claps her hands and hears the echo 0.250 s later. If the speed of sound was 340.0 m/s, how far from the wall was she?

42.5m

Explanation:

How far does sound travel in 0.25 s at a speed of 340 m/s?

d = v*t = 85 m

Sound travels from her hands to the wall, bounces off and comes back.

So the distance traveled is twice the length from the wall.

d = 2L

L = d/2

L = 42.5 m.

wavelength divides in half and speed stays the same.

find the surface area of the sphere to the nearest square unit. use a calculator.

a. 254 in.2

b. 64 in.2

c. 127 in.2

d. 1,018 in.2