I do after school tutoring for Math and Science. Whenever I come across a problem or strategy I like, I post it here. I am also working on a series called "The Math of 'The Martian'" In which I pull out Jr High and High School level Math and Science problems from the book "The Martian"
Saturday, March 19, 2016
Multi-part geometry problem
One side of a right scalene triangle is 100. The perimeter is 240. A similar triangle has a scale factor of 3:5 (new:old). Find the perimeter of the new triangle. Find both possible sets of solutions for the other two sides of the new triangle.
Monday, March 14, 2016
The Math of "The Martian" Sol 98
These are the first two messages that
Watney received today. Translate them from ASCII:
Message 1:
434e48414b52565232544c4b32505448464452505250344c4f4e474d5347
Message 2:
4c4e4348686578696469744f4e525652434d502c4f50454e46494c452d2f7573722f6c69622f686162636f6d6d2e736f2d5343524f4c4c54494c4944584f4e4c465449533a32414145352c4f565257525431343142595453575448444154415745274c4c534e444e58544d53472c5354414e44494e56494557344e45585450494332304d494e41465452544853444f4e45
The Math of "The Martian" Sol 97 (2) Solution
Sol 97 (2) SOLUTION
Mark instructed NASA to time their
transmissions so they arrived at the top of every hour, with their first
transmission arriving at 11:00am. Which means the last transmission from NASA
arrived at 5:00pm. Marks’s first note would have to be placed up at least 32
minutes before 11:00 am, so this entire conversation took at least 6 hours and
32 minutes.
ASCII conversions:
STATUS: 535441545553
HOWALIVE: 484F57414C495645
CROPS?: 43524F50533F
WESAW-SATLITE: 57455341572D5341544C495445
BRINGSJRNROUT: 4252494E47534A524E524F5554
SJRNRNOTRSPND: 534A524E534E4F545253504E44
WORKINGONIT: 574F524B494E474F4E4954
Saturday, March 5, 2016
The Math of "The Martian" Sol 97 (2)
Sol 97 (2)
Mark has fixed the Pathfinder lander to
communicate with earth! Although it will be tedious, the story states that
earth and Mars are currently 16 light minutes apart. He can hand write messages
on note cards and place them in view of the camera, getting a response is much
more tricky. Mark has decided to tell NASA to use ASCII to spell messages. He
placed then numbers 0 through 9, and the letters A through F in a circle around
the lander. NASA can select one by pointing to the camera at it. The following
is their’ first day’s worth of communication:
Mark: Spell with ASCII. 0-F at 21-degree
increments. Will watch camera staring 11:00 my time. When message done, return
to this position. Wait 20 minutes after completion to take picture (so I can
write and post reply). Repeat process at top of every hour.
NASA: STATUS
Mark: No physical problems. All Hab
components functional. Eating ¾ rations. Successfully growing crops in Hab with
cultivates soil. Note: Situation not Ares 3 crew’s fault. Bad luck.
NASA: HOWALIVE
Mark: Impaled by antenna fragment.
Knocked out by decompression. Landed facedown, blood sealed hole. Woke up after
crew left. Bio-monitor computer destroyed by puncture. Crew had reason to think
me dead. Not their fault.
NASA: CROPS?
Mark: Long story. Extreme botany. Have
126 m2 farmland growing potatoes. Will extend food supply, but not enough to
last until Ares 4 landing. Modified rover for long-distance travel, plan to
drive to Ares 4.
NASA: WESAW-SATLITE
Mark: Government watching me with
satellites? Need tinfoil hat! Also need faster way to communicate.
Speak&Spell taking all damn day. Any ideas?
NASA: BRINGSJRNROUT
Mark: Sojourner rover brought out, placed
1 meter due north of lander. If you can concoct it, I can draw hex numbers on
the wheels and you can send me six bytes at a time.
NASA: SJRNRNOTRSPND
Mark: Damn. Any other ideas? Need faster
communication.
NASA: WORKINGONIT
Mark: Earth is about to set. Resume 08:00
my time tomorrow morning. Tell family I’m fine. Give crew my best. Tell
Commander Lewis disco sucks.
How long did this conversation take?
Convert NASA’s transmissions back into
ASCII.
Wednesday, March 2, 2016
The Math of "The Martian" Sol 83
Mark is retrieving the Pathfinder space
probe in hopes of fixing it’s radio so that he can communicate with earth. He
is at Pathfinder’s landing site, but he needs to get the probe onto the roof of
his rover. He has removed several parts of the probe that he won’t need, but it
still has a mass of 200 kg. How much would that weigh on Earth? How much would
that weigh on Mars?
He has decided that the best way to get
it up to the top of the rover is to use rocks to build a ramp. After some small
scale experiments he has determined that the best angle for the ramp will be 30
degrees. If the rover is 2.5m tall, how long will the base of the ramp be?
If the ramp is 1m wide, and the rocks in
the area have a density of 3 g/cm^3, what is the upper limit of the mass of
rocks must he move to create his ramp? How much does this weigh on Mars?
Tuesday, March 1, 2016
classdojo.com
The teacher I sub'ed for today used classdojo.com to keep track of class behavior. IT'S AMAZING! I wish all of the teachers I sub for used it!
The Math of "The Martian" Sol 71
Mark is planning on testing his long
distance modifications to the Rover with a long distance trip.
The Hab is
located at 31.2 degrees north, 28.5 degrees west. He plans to go to 19.13
degrees north, 33.22 degrees west, and back. How far is that? How many Sols
will the trip take?
The Rover’s Oxygen tanks hold enough for 7 Sols. If Mark
needs 588 Liters of gaseous Oxygen per Sol, how much liquid Oxygen does he need
to make up the difference? If the Hab has two 25 Liter liquid Oxygen tanks,
will he need to take one or both?
His potatoes aren’t ready to harvest yet,
so he will need to take ration packs with him. What is the minimum amount of packs
that he will he need to take?
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