1) 3 miles/Hour
The speed is defined as the distance covered divided by the time taken:
where
d = 1.5 mi is the distance
t = 0.5 h is the time taken
Substituting,
2) 1.34 m/s south
Velocity, instead, is a vector, so it has both a magnitude and a direction. We have:
is the displacement in meters
is the time taken in seconds
Substituting,
And the direction of the velocity is the same as the displacement, so it is south.
Answer:
Radio waves have a wavelength between and
While,
X rays have a wavelength between 1m and 10km.
=> It is one of the condition of diffraction that the obstacle (coming in the way) must be comparable with the size of the wavelength.
=> This shows, that radio waves have a wavelength which is comparable with the size of buildings and can really easily diffract through it
=> While, X-rays are big enough to diffract through the wall.
So, if an X-ray technician stands behind a wall during the use of her machine, she will remain safe.