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PolarNik [594]
3 years ago
8

Bart awoke screaming, shaking, and sweating in his heart was beating rapidly. Homer and Marge, being good parents, had Bart hook

ed up to an EEG. Checking Bart's EEG, they noted that Bart was in stage 4 sleep just before he awoke. From this information, they felt confident in saying that Bart had just experienced __________.
a. a lucid dream
b. an episode of sleep apnea
c. a nightmare
d. sleep terror disorder
Physics
1 answer:
Nuetrik [128]3 years ago
7 0

Answer: D

sleep terror disorder

Explanation:

It is a sleeping disorder causing feelings of panic or dread which typically occur during the first hours of stage 3–4 non-rapid eye movement (NREM) sleep.

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A small package is attached to a helium-filled balloon rising at 2 m/s. The package drops from the balloon when it is 14 meters
scZoUnD [109]
I would assume air resistance is negligible and so the acceleration of the package would be approximately 9.81 m/s².

Taking downwards as positive, use v²=u²+2as.
v²=(-2)²+2(9.81)(14)
v=16.7 m/s
4 0
3 years ago
Barnard’s Star is a red dwarf. It is located 5.9 light years from Earth. (One light year is the same as 9.46 trillion kilometers
mote1985 [20]
A star is located 5.9 light years from Earth.
We know that : 1 light year = 9.46  trillion kilometers.
We will calculate the distance in trillion kilometers multiplying the number of light years by 9.46:
5.9 * 9.46 = 55.814
Answer: The distance is 55.814 trillion km.
5 0
3 years ago
Read 2 more answers
An electron is released from rest at a distance of 6.00 cm from a proton. If the proton is held in place, how fast will the elec
lana66690 [7]

Answer:

91.87 m/s

Explanation:

<u>Given:</u>

  • x = initial distance of the electron from the proton = 6 cm = 0.06 m
  • y = initial distance of the electron from the proton = 3 cm = 0.03 m
  • u = initial velocity of the electron = 0 m/s

<u>Assume:</u>

  • m = mass of an electron = 9.1\times 10^{-31}\ kg
  • v = final velocity of the electron
  • e = magnitude of charge on an electron = 1.6\times 10^{-19}\ C
  • p = magnitude of charge on a proton = 1.6\times 10^{-19}\ C

We know that only only electric field due to proton causes to move from a distance of 6 cm from proton to 3 cm distance from it. This means the electric force force does work on the electron to move it from one initial position to the final position which is equal to the change in potential energy of the electron due to proton.

Now, according to the work-energy theorem, the total work done by the electric force on the electron due to proton is equal to the kinetic energy change in it.

\therefore \textrm{Kinetic energy change}= \textrm{Change in potential energy}\\\Rightarrow \dfrac{1}{2}m(v^2-u^2)= \dfrac{kpe}{y}-\dfrac{kpe}{x}\\\Rightarrow \dfrac{1}{2}m(v^2-(0)^2)= \dfrac{kpe}{0.03}-\dfrac{kpe}{0.06}\\\Rightarrow \dfrac{1}{2}mv^2= \dfrac{100kpe}{3}-\dfrac{100kpe}{6}\\\Rightarrow \dfrac{1}{2}mv^2= \dfrac{100kpe}{6}\\

\Rightarrow v^2= \dfrac{100kpe\times 2}{6m}\\\Rightarrow v^2= \dfrac{100kpe}{3m}\\\Rightarrow v^2= \dfrac{100\times 9\times 10^9\times 1.6\times 10^{-19}\times 1.6\times 10^{-19}}{3\times 9.1\times 10^{-31}}\\\Rightarrow v^2=8.44\times 10^3\\\Rightarrow v=91.87\ m/s\\

Hence, when the electron is at a distance of c cm from the proton, it moves with a velocity of 91.87 m/s.

8 0
3 years ago
Driving on asphalt roads entails very little rolling resistance, so most of the energy of the engine goes to overcoming air resi
Bad White [126]
A) Agreed. 
<span>b) Value agreed but units should be W (watts). </span>

<span>c) Here's one method... </span>

<span>15 miles = 24140 m </span>

<span>1 gallon of gasoline contains 1.4×10⁸ J. </span>

<span>So moving a distance of 24140m requires gasoline containing 1.4×10⁸ J </span>

<span>Therefore moving a distance of 1m requires gasoline containing 1.4×10⁸/24140 = 5800 J </span>

<span>Overcoming rolling resitance for 1m requires (useful) work = force x distance = 1000x1 = 1000J </span>

<span>So 5800J (in the gasoline) provides 1000J (overcoming rolling resistance) of useful work for each metre moved. </span>

<span>Efficiency = useful work/total energy supplied </span>
<span>= 1000/5800 </span>
<span>= 0.17 (=17%) </span>
8 0
3 years ago
A rock weighing 98 newtons is pushed off the edge of a bridge 50 meters above the ground. What was the kinetic energy of the roc
Ahat [919]
2,450 Joules,  kinetic energy is 1/2 mass x velocity squared.
3 0
3 years ago
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