I notice that even though we're working with frames of reference
here, you never said which frame the '5 km/hr' is measured in.
In fact ! You didn't even say which frame the '12 km/hr' of his
bike is measured in.
So there are several different ways this could go. I'll do it the way
I THINK you meant it, but that doesn't guarantee anything.
-- Simon is riding his bike at 12 km/hr relative to the sidewalk,
away from Keesha.
-- He throws a ball at Keesha, at 5 km/hr relative to his own face.
-- Keesha sees the ball approaching her at (12 - 5) = 7 km/hr
relative to the ground and to her.
(a) Period of the wave
The period of a wave is the time needed for a complete cycle of the wave to pass through a certain point.
So, if an entire cycle of the wave passes through the given location in 5.0 seconds, this means that the period is equal to 5.0 s: T=5.0 s.
(b) Frequency of the wave
The frequency of a wave is defined as

since in our problem the period is

, the frequency is

(c) Speed of the wave
The speed of a wave is given by the following relationship between frequency f and wavelength

:
The point at which all motion stops.
<span><u><em>This begins with the sun’s radiation,
which is absorbed differently on the earth’s surface. The earth's
surface is heated differently because of scenarios like cloud cover,
mountains, valleys, water bodies, vegetation and desert lands.</em></u>
<u><em></em></u>
<u><em>Good luck! </em></u></span><u><em></em></u>
Formulated in the 1980s by Robert Sternberg<span>, the </span>triarchic theory<span> distinguishes three aspects of </span>intelligence<span>: analytic skills, such as the ability to think abstractly and evaluate </span>information<span>; creativity, the ability to invent novel solutions or ideas; and practical skills, which enable one to cope with concrete ...</span>