It's the angle made by the incident ray when it's perpendicular to the surface. (Perpendicular lines are the lines that form a graph or like a 90-degree angle)
Answer: The wave can flip upside down.
Reflection is the bending of a wave when it cannot pass through. For example, plain mirrors which are flat, a ray of light hits the mirror and is reflected from the mirror since it cannot pass through
When reflection occurs the speed and frequency of the wave does not change but the wave is flipped upside down.
The speed does not change because speed is affected by the change in medium the frequency also remains the same since the energy of the wave does not change.
Before the engines fail
, the rocket's horizontal and vertical position in the air are


and its velocity vector has components


After
, its position is


and the rocket's velocity vector has horizontal and vertical components


After the engine failure
, the rocket is in freefall and its position is given by


and its velocity vector's components are


where we take
.
a. The maximum altitude occurs at the point during which
:

At this point, the rocket has an altitude of

b. The rocket will eventually fall to the ground at some point after its engines fail. We solve
for
, then add 3 seconds to this time:

So the rocket stays in the air for a total of
.
c. After the engine failure, the rocket traveled for about 34.6 seconds, so we evalute
for this time
:

Answer: The Company has spent $5 million in research and development over the past 12 months developing cutting-edge battery technology which will be incorporated ...
Explanation: uhmmmmmm i dont know this one but it is pretty ez
There's a crest and a trough in each complete wave. So the question is describing 10 complete waves.
After that, the question becomes somewhat murky. It goes on to say "its time period is 0.2 seconds".
-- The "time period" of a wave is usually defined as the time for <u><em>one</em></u> complete wave. If that's what the phrase means, then ...
Frequency = ( 1/0.2sec )
<em>Frequency = 5 Hz.</em>
<em>= = = = = = = = = =</em>
<u>BUT</u> ... Is the question awkwardly trying to tell us that the <u><em>10 waves</em></u> take 0.2 seconds ? If that's what it's saying, then ...
Frequency = (10) / (0.2 sec)
<em>Frequency = 50 Hz .</em>