De broglie wavelength, , where h is the Planck's constant, m is the mass and v is the velocity.
Mass of hydrogen atom,
v = 440 m/s
Substituting
Wavelength
So the de broglie wavelength (in picometers) of a hydrogen atom traveling at 440 m/s is 902 pm
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.