Physics, 28.01.2020 06:31 mangowammy

An alien spaceship streaks past spanos football stadium along the direction of play at 0.8c. a football field is 120 yards long by 55 yards wide. eager to learn about earth games, an alien on the spaceship makes some measurements. conveniently the alien has already studied earth units of measurement. (i) what does the alien measure for the length and width of the stadium? (ii) the game begins at 1: 30 pm pacific standard time (pst) and ends at 4: 30 pm pst. how much time has elapsed according to the alien? (iii) who sees the proper length of the stadium? why? (iv) who sees the proper time for the game? why?

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(i) Length of stadium, L₀ = 72 yards; width of stadium W = 55 yards (ii) 5 hours (iii) The people on earth. This is because they are not moving at relativistic speed relative to the game. (iv) The people on earth. This is because they are not moving at relativistic speed relative to the game.

Explanation:

(i) Given Length of stadium, L₀ = 120 yards, width of stadium, W₀ = 55 yards, speed of alien spaceship in direction of play, v = 0.8c

We use the equation for length contraction to determine the length of stadium L measured by the alien spaceship, since it is moving in the direction of game play and length contraction only occurs in the direction of motion. So, L = $\sqrt{1-\beta^{2} }$ L₀ where β = $\frac{v}{c}$ v= speed of alien spaceship and c= speed of light. So, β = $\frac{v}{c}$ = $\frac{0.8c}{c}$ = 0.8. Therefore, L = $\sqrt{1-0.8^{2} }$ L₀= $\sqrt{1-0.64}$ L₀= $\sqrt{0.36}$ L₀ = 0.6L₀ = 0.6 × 120 = 72 yards. So, the alien spaceship measures a length of 72 yards. The alien spaceship measures a width,W of 55 yards because there is no length contraction in the direction perpendicular to that of its motion. So, W = W₀ = 55 yards.

(ii) Since the game begins at 1:30 PM Pacific Standard Time (PST) and ends 4:30 PM Pacific Standard Time (PST), the proper time t₀, which is the duration of the event is 4:30 - 1:30 = 3 hours. The time measured by the alien spaceship t (since the time dilates)is given by t = t₀/ $\sqrt{1 - \beta ^{2} }$ . From (i) above β = 0.8 and t₀ = 3 hours. So, t = 3/ $\sqrt{1 - 0.8^{2} }$ = 3/0.6 = 5 hours.

(iii) The people in Spanos football stadium. This is because they are not moving at relativistic speed relative to the game. Since $\frac{v}{c}$ ≈ 0 then β ≈ 0 So, L = $\sqrt{1-\beta^{2} }$ L₀= So, L = $\sqrt{1-0}$ L₀thus L = L₀ for the spectators in spanos football field (iv) The people in Spanos football stadium. This is because they are not moving at relativistic speed relative to the game. Since $\frac{v}{c}$ ≈ 0 then β ≈ 0. So, t = t₀/ $\sqrt{1 - \beta ^{2} }$ = t₀/ $\sqrt{1-0}$ = t₀.Thus t = t₀ for the spectators in spanos football field.

Answer from: Quest

quantum mechanics or quantum physics is physics of very small objects (particles) and physical entities.

quantum physics has some parallels to our macro world and some pretty unique ideas which theoretically and mathematically proven to be true even though we will never be able to access them because of our size.

there are many types of particles: subatomic, elementary etc.

subatomic means they are smaller than atom, elementary means they are at the very basis of everything.

subatomic particles are for eg. protons, neutrons but not electrons.

elementary particles are categorised into 3 groups by what they do.

these 3 groups are quarks, leptons and bosons.

light for example is a particle more precisely a photon a part of leptons.

proton (subatomic particle) is made out of 2 up quarks and 1 down quark each of these has a fractional charge like $\frac{1}{3}$ . (i crazy)

most famous scientist who contributed to this physics are:

max planckalbert einsteinerwin schrödingermany

the topic itself us understand a lot and will probably be vastly used in the future (quantum computers, understanding the big bang,

we also must not forget quantum effects like:

superposition (where 1 thing can be this and that at the same time),entanglement (where two particles are seemingly connected by some sort of unknown (or known) force, energy, matter (i know all that can be the same at least it was at the beginning)

and there is more. but probably too much for this answer to be consistent due to my average understanding of this topic.

hope this you understand quantum mechanics a little more. i'm not an expert in the topic (so don't be like wth if you are an expert) but i'm very interested in it.

anyways quantum physics is a very hard topic (harder than physics (perhaps)) therefore searching for every information there is about it and learning it is unfortunately impossible (you can only specialise into 1 - 3 things or more (perhaps

have fun and i wish you luck!

r3t40

Answer from: Quest

Iread this book last year so take this with a grain of salt.gene jumps from the tree to compete with finny due to the fact that gene is always trying to do better than finny. he is put under the grasp of peer pressure due to finny almost forcing him to do this. ever since he first jumped finny kept pressuring him to jump since he thought gene enjoyed jumping.rather than uses this answer you should probably just reread chapters 3-4

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