there was a lot of little bits of info today, so instead of ranting about all of it and wasting my time, i'll just say refer to "comparison of introduced and native pasture species/pastures"
its a big table with 3 columns.
the general geist is that introduced pastures are more tasty, digestible, nutritious and contain more energy, however native plants are more resistant to weeds, extreme climate and dont necessarily need re-sowing after grazing. however they dont withstand heavy grazing as well as introduced species do.
overall native species are more sustainable coz they dont cost as much and you dont need to pay for things to protect them from weeds and climate and such as much.
one last thing we did was seeing the relationsb etween pasture quality and animal production quality.
eg. irrigating pasture will maximize photosynthesis, thus growth & nutrient uptake, making more nutritious and delicious plants, and so cows produce more milk
Monday, November 30, 2009
phys (1130) - Space: conservation of momentum
man i shouldve been paying more attention instead of doing maths, but i had tests to prepare for.. but i managed to get SMOEthing into my head.
we all know newton's second law, F = ma, now rockets move because there's a net force. that is, a netforce acting upwards, that's higher than gravity (something different to reaction force coz thats only enough to counter gravity, not push the rocket further)
the rocket burns fuel, it pushes it out, and as a result the fuel pushes the rocket upwards (newton's third law)
robson derrived the formula for momentum (p) from F = ma today, it goes like this
F = ma [where a = (v-u)/t]
F = m((v-u)/t)
F = (mv-mu)/t
Ft = mv - mu = /\p
see?
we all know newton's second law, F = ma, now rockets move because there's a net force. that is, a netforce acting upwards, that's higher than gravity (something different to reaction force coz thats only enough to counter gravity, not push the rocket further)
the rocket burns fuel, it pushes it out, and as a result the fuel pushes the rocket upwards (newton's third law)
robson derrived the formula for momentum (p) from F = ma today, it goes like this
F = ma [where a = (v-u)/t]
F = m((v-u)/t)
F = (mv-mu)/t
Ft = mv - mu = /\p
see?
Saturday, November 28, 2009
phys (1127) - satellites to planets 2
today.. we went over.. just one concept i think.. one concept with multiple aspects.
it's that the movement of the earth affects the movement of the satellites that we launch.
mr robson described the axis spinning sort of like jumping off a moving train. when we jump, we still have the velocity from when we were on the train (aka, we're moving sideways though we dont realize)
that is why, launches are preferably done near the equator (rotational veloctiy is at its max there) and using the earth's rotational velocity to give the rocket extra speed is a good idea. 11km/s is the requried escape velocity to get out of the earth's gravity.
the earth is going anticlockwise (from looking above the north pole) around the sun, at a speed of approx 29km/s, so in theory.. satellites we launch are also following that same path, with that same speed. so to fire rockets in the opposite direction, unless they exceed 29km/s, the result wuold just be the rocket slows down and is pulled towards the sun. if its fired in the same direction, it escapes earth's orbit and goes elsewhere.
also.. i asked if all the planets were on the same plane.. turns out they are.. with the exception of pluto. i suppose they're in line with the sun's.. "equator"
also, before the lesson, as a question of gerenal interest i asked what fire is. no full explanation as yuet, it's not something that can be easily explained. but what we see and feel of the fire is energy for sure, but fire itself is more like.. a reaction.
it's that the movement of the earth affects the movement of the satellites that we launch.
mr robson described the axis spinning sort of like jumping off a moving train. when we jump, we still have the velocity from when we were on the train (aka, we're moving sideways though we dont realize)
that is why, launches are preferably done near the equator (rotational veloctiy is at its max there) and using the earth's rotational velocity to give the rocket extra speed is a good idea. 11km/s is the requried escape velocity to get out of the earth's gravity.
the earth is going anticlockwise (from looking above the north pole) around the sun, at a speed of approx 29km/s, so in theory.. satellites we launch are also following that same path, with that same speed. so to fire rockets in the opposite direction, unless they exceed 29km/s, the result wuold just be the rocket slows down and is pulled towards the sun. if its fired in the same direction, it escapes earth's orbit and goes elsewhere.
also.. i asked if all the planets were on the same plane.. turns out they are.. with the exception of pluto. i suppose they're in line with the sun's.. "equator"
also, before the lesson, as a question of gerenal interest i asked what fire is. no full explanation as yuet, it's not something that can be easily explained. but what we see and feel of the fire is energy for sure, but fire itself is more like.. a reaction.
ag (1127) - Lettuce: kgDM
using the data we've collceted, we calculated the the amount of dry matter (kgDM) in the two paddocks (1.8ha of ryegrass, 1.5ha of lucerne)
dry matter is everything in the plant that is not water (plants are 70-80% water) so this includes vitamins, minerals, carbohydrates, sugars, oils, etc.
for both, we calculated approx how long each paddock would be able to feed 20x 500kg beef cows (leaving approx 15cm of the pasture leftover to regrow)
i cant rememember fully coz i dont have the sheet, it was collected.
but we had to match up our average (-15 for reserve) with a graph that deteremined the DM in each pasture plant (depending on density)
after that.. we know that beef cows eat approx 3.5% of their weight a day, so we had to work that out.. and put the total DM we get over the required DM
the result was the amount of days that the paddock could last.
thing was that not all of the pasture would be eaten though, much of it would be trampled. so these readings arent always as accurate as they can be
dry matter is everything in the plant that is not water (plants are 70-80% water) so this includes vitamins, minerals, carbohydrates, sugars, oils, etc.
for both, we calculated approx how long each paddock would be able to feed 20x 500kg beef cows (leaving approx 15cm of the pasture leftover to regrow)
i cant rememember fully coz i dont have the sheet, it was collected.
but we had to match up our average (-15 for reserve) with a graph that deteremined the DM in each pasture plant (depending on density)
after that.. we know that beef cows eat approx 3.5% of their weight a day, so we had to work that out.. and put the total DM we get over the required DM
the result was the amount of days that the paddock could last.
thing was that not all of the pasture would be eaten though, much of it would be trampled. so these readings arent always as accurate as they can be
math (1127) - Quad: quadratic identities
pretty straight forward, if two expressions are equivalent, all the corresponding coefficients must be equal.
you can use this to solve retarded versions of the quadratic function y = ax^2 + bx + c
i dont know what i can say.. its so weird
you can use this to solve retarded versions of the quadratic function y = ax^2 + bx + c
i dont know what i can say.. its so weird
Thursday, November 26, 2009
ext2 (1124) - day 5: concept
in my confusion yesterday of double-day note-making, i forgot that i in fact was present at extension 2 on tuesday.
the teacher let me be coz i was unable to complete the tasks assigned coz i got sick last friday 'til monday, but at least i got to hear everyone elses.
however, if i did mine i found out it would've been lacking anyway. even though we were meant to write from the perspective of that random character again, we neeeded a concept.
the teacher explained that concept is a thematic thing, and its based on values of the time of the story, to give the story a meaning, make a comment on something, etc.
well i was told to do it anyway, even though i don't necessarily submit it.
our next task is using the setting we described last week, write about an event. and give one of the characters a voice, take their role; their persona.
also, i got to talk about my ideas for my movie more. the two ideas, either about the two peoples lives, or the one guy's life split into his past self and his present self. an issue would be time restraint. i've noticed for the other movies (i've been looking through the scripts) made, the scripts are like 7 pages, with hardly any talking.
but it's alright, i didnt wanna have much talking anyway.. but somehow i need to find a relevant and good story, and tell it within 8 minutes. hmm..
its like a minute a page approx, i need to really think about this.
first things first, if i cant think of a story for now, i'll at least look up how to write a script. that's a good starting point
the teacher let me be coz i was unable to complete the tasks assigned coz i got sick last friday 'til monday, but at least i got to hear everyone elses.
however, if i did mine i found out it would've been lacking anyway. even though we were meant to write from the perspective of that random character again, we neeeded a concept.
the teacher explained that concept is a thematic thing, and its based on values of the time of the story, to give the story a meaning, make a comment on something, etc.
well i was told to do it anyway, even though i don't necessarily submit it.
our next task is using the setting we described last week, write about an event. and give one of the characters a voice, take their role; their persona.
also, i got to talk about my ideas for my movie more. the two ideas, either about the two peoples lives, or the one guy's life split into his past self and his present self. an issue would be time restraint. i've noticed for the other movies (i've been looking through the scripts) made, the scripts are like 7 pages, with hardly any talking.
but it's alright, i didnt wanna have much talking anyway.. but somehow i need to find a relevant and good story, and tell it within 8 minutes. hmm..
its like a minute a page approx, i need to really think about this.
first things first, if i cant think of a story for now, i'll at least look up how to write a script. that's a good starting point
math (1126) - Quad: discriminant
got rather scared today when i found out our marks will always be compared to the rest of the grade from now on.
eep -.-
and theres so many more 3u people than us.
gay.
anyway.. besides seeing the proof of how the quadratic formula came to be, we worked with just one simple rule with discriminants.
let y = ax^2 + bx + c
if /\ < 0, y has no real roots, aka doenst collide witht he x-axis
now in terms of taht
if a > 0, and /\ <> 0 for all x values (aka the graph is concave up and above the x-axis)
if a < 0, and /\ < 0, the function is negative definite, and y < 0 for all x values (aka the graph is concave down and below the x-axis
eep -.-
and theres so many more 3u people than us.
gay.
anyway.. besides seeing the proof of how the quadratic formula came to be, we worked with just one simple rule with discriminants.
let y = ax^2 + bx + c
if /\ < 0, y has no real roots, aka doenst collide witht he x-axis
now in terms of taht
if a > 0, and /\ <> 0 for all x values (aka the graph is concave up and above the x-axis)
if a < 0, and /\ < 0, the function is negative definite, and y < 0 for all x values (aka the graph is concave down and below the x-axis
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