Answer:
There are four different stages of sleep.
Stage 1 NREM
Explanation:
<em>The process of firmly falling asleep has four stages through which a person goes.</em>
<em>It goes from being awake over light sleep and falling firmly into sleeping.</em>
(STAGE 1)
This is a stage in which there are non-rapid movements of the eyes. In other words, it is a process of dreamless sleep. You enter this stage the moment you decide to sleep and shut your eyes. After several minutes, your body is in fact in the sleeping mode, but not entirely. This means that you can easily be woken up without being aware that you have slept.
Features:
- <em>You can easily awake</em>
- <em>Your may roll and they may be a little open</em>
- <em>The blood pressure and the temperature of the brain start to decrease </em>
- <em>You experience the natural human reflexes that the brain sends to assure that the place of your sleep is in a safe environment. By sending twitches to your muscles, your brain may awake your body for several seconds which comes in handy if you are tired and close to sleep on work or some dangerous place like a cliff for example.</em>
- <em>Your breading starts to slow down alongside with your pressure and temperature, and your heartbeats slow down.</em>
Total internal reflection complete reflection of a ray of light within a medium such as water or glass from the surrounding surfaces back into the medium. The phenomenon occurs if the angle of incidence is greater than a certain limiting angle, called the critical angle.
Answer:
a. 
Explanation:
The equation of the forces along the directions parallel and perpendicular to the slope are:
- Along the parallel direction:
where
:
m = 6.0 kg is the mass of the box
g = 9.8 m/s^2 the acceleration of gravity
is the angle of the slope
is the coefficient of friction
R is the normal reaction
a is the acceleration
- Along the perpendicular direction:
From the 2nd equation, we get an expression for the reaction force:
And substituting into the 1st equation, we can find the acceleration:
Solving for a,
According to Newton's 3rd law, there will be equal and opposite force on the astronaut which is -6048 N
<h3>
What does Newton's third law say ?</h3>
The law state that in every action, there will be equal and opposite reaction.
Given that a rocket takes off from Earth's surface, accelerating straight up at 69.2 m/s2. We are to calculate the normal force (in N) acting on an astronaut of mass 87.4 kg, including his space suit.
Let us first calculate the force involved in the acceleration of the rocket by using the formula
F = ma
Where mass m = 87.4 kg, acceleration a = 69.2 m/s2
Substitute the two parameters into the formula
F = 87.4 x 69.2
F = 6048.08 N
According to the Newton's 3rd law, there will be equal and opposite force on the astronaut.
Therefore, the normal force acting on the astronaut is -6048 N approximately
Learn more about forces here: brainly.com/question/12970081
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Answer:
Explanation:
Δ
- Δ
is the difference in velocity before and after a given time. 
is the acceleration of the object during this time. 
is time
is another way to write this equation.
- The Δ symbol represents "the difference between the initial and final values of a magnitude or vector", so Δ
- I rearranged this equation to solve for , but this is a step that you don't need to take, it's just good to get in the habit of doing this.
- Plug in the given values. Note that our final velocity is
, because the car travels until at <em>rest</em>.
![a=\frac{v_f-v_i}{t}\\a=\frac{(0)-[(17.1\frac{miles}{hour} )(\frac{hour}{3600s})(\frac{1609.34m}{mile})]}{9.7s}](https://tex.z-dn.net/?f=a%3D%5Cfrac%7Bv_f-v_i%7D%7Bt%7D%5C%5Ca%3D%5Cfrac%7B%280%29-%5B%2817.1%5Cfrac%7Bmiles%7D%7Bhour%7D%20%29%28%5Cfrac%7Bhour%7D%7B3600s%7D%29%28%5Cfrac%7B1609.34m%7D%7Bmile%7D%29%5D%7D%7B9.7s%7D)
- Our initial velocity is in mph, something not in standard units, so if not changed, you will get an incorrect answer. What you need to do is cancel out the units your prior value had using division and multiplication, and at the same time multiply and divide the correct numbers and units into your equation. Or look up a converter.
![a=\frac{(0)-[(17.1\frac{miles}{hour} )(\frac{hour}{3600s})(\frac{1609.34m}{mile})]}{9.7s}\\a=\frac{0m/s-7.6m/s}{9.7s} \\a=\frac{-7.6m/s}{9.7s}](https://tex.z-dn.net/?f=a%3D%5Cfrac%7B%280%29-%5B%2817.1%5Cfrac%7Bmiles%7D%7Bhour%7D%20%29%28%5Cfrac%7Bhour%7D%7B3600s%7D%29%28%5Cfrac%7B1609.34m%7D%7Bmile%7D%29%5D%7D%7B9.7s%7D%5C%5Ca%3D%5Cfrac%7B0m%2Fs-7.6m%2Fs%7D%7B9.7s%7D%20%5C%5Ca%3D%5Cfrac%7B-7.6m%2Fs%7D%7B9.7s%7D)
- if you converted correctly, your answer for
will be ≅ 
. - Now divide. Notice that the units for acceleration are
or <em>meters per second, per second</em>.
- Our final answer is <em>negative </em>because the car is <em>slowing down</em>. Do not square this answer as the square symbol only applies to the units, not the magnitude.
