Hi everyone! I need help on these two problems:(adsbygoogle = window.adsbygoogle || []).push({});

1.) A flower pot is knocked off a balcony 20m above the sidewalk and falls toward an unsuspecting 1.75-m-tall man who is standing below. How close to the sidewalk can the flower pot fall before it is too late for a shouted warning from the balcony to reach the man in time? Assume that the man below requires .3 s to respond to the warning.

Would I use the formula:

v=(d)/(delta t)? If so how?

The answer is 7.82m

2. Consider the sinusoidal wave, with the wave function:

y=(15 cm) cos(.157x-50.3t)

At a certain instant, let point A be at the origin and point B be the first point along the x axis where the wave is 60 degrees out of phase with point A. What is the coordinate of point B?

I did:

y=(15 cm) cos(.157x-50.3t)=60

15cos(.157x)=60

cos(.157x)=4 and this is impossible

I have no clue what to do.

~Thanks

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Sound waves and wave motion

**Physics Forums | Science Articles, Homework Help, Discussion**