I believe it goes as the following::
1) Waves transfer energy without moving particles
2) The two types of waves are longitudinal and transverse waves OR The two types of waves are mechanical and electromagnetic waves. Both are applicable and should be correct!
Answer:
Frequency, 
Explanation:
We have,
Speed of radio waves is 
Wavelength of radio waves is 
It is required to find the frequency of the radio waves. The speed of a wave is given by :

So, the frequency of the radio wave is
.
The point obviously is in the 3rs quadrant
So
စ= tan^-1( y/x)-180
စ= -89.7°
Answer:
0.79 s
Explanation:
We have to calculate the employee acceleration, in order to know the minimum time. According to Newton's second law:

The frictional force is maximum since the employee has to apply a maximum force to spend the minimum time. In y axis the employee's acceleration is zero, so the net force is zero. Recall that 
Now, we find the acceleration:

Finally, using an uniformly accelerated motion formula, we can calculate the minimum time. The employee starts at rest, thus his initial speed is zero:

"<em>The different types of radiation are defined by the the amount of </em><em>energy</em><em> found in the photons. Radio </em><em>waves</em><em> have photons with low energies, microwave photons have a little </em><em>more energy</em><em> than radio </em><em>waves</em><em>, infrared photons have still </em><em>more</em><em>, then visible, ultraviolet, X-rays, and, the </em><em>most</em><em> energetic of all, gamma-rays.</em>"