# Posts by sacroima

• ## Chapter 4

Let's calculate all the different options :

First, the travel time if the Jumbo Jupiter can do the trip at full speed : 620km at 300km/h takes 2hours and 4 minutes to complete.

Option 1 : A four hour delay would mean they miss their train in Hicksburg (4h + travel time > 6hours)

>> no point in going for option 1, better to simply cancel than perform the emergency fix to no avail.

Now let's investigate option 3 : 90min delay + travel time >> they would arrive before midnight and would get their connection. The price of the new motor is 12'000\$, much less than the 30'000 needed if they miss their connecting train.

Finally, option 4 : 40% of 300 km/h = 120 km/h. It would now take 5hours and 10min to do the trip. This would mean the passengers would arrive at 11:40pm, 20min before their connection departs. This also doesn't cost anything to the company.

Therefore, option 4 is the best option. People would get their connection, the company wouldn't have to pay anything, and could even use part of the economy (12'000\$ for the motor) to give some compensation to the passengers (a drink or sandwich in the train for example).

• ## Chapter 3

let's give some weight to each criterium :

punctuality = 1

price = 2

durability = 4

Now we give points (1 = bad, 2 = average, 3 = best) to each good for each criterium :

Mecha-Heads : punctuality = 2 ; price = 3; durability = 1;

Swiss Metal : punctuality = 3 ; price = 1; durability = 3;

General Machines : punctuality = 3; price = 2; durability = 2;

we then multiply with the weight to finally have that Swiss Metal scores better than General Machines and Mecha-Heads are the worst.

More simply, we could just see that Swiss Metal and General Machines score the same in punctuality, and are reversed on price and durability, but durability is more important to the manager. So we select the one with the best durability, since Mecha-Heads scores poorly.

• ## Chapter 2

LoL, I'm gonna get fired if I don't score 10 here

Q1 : 2.B

Q2 : 4.the scissors. too heavy for the contact surface. Haven't often seen bananas float either though

Q3 : 1.A

Q4 : 2.B (at point A and C, he will be losing speed)

Q5 : 1.A

Q6 : 1.20 counterclockwise

Q7 : 4.2.5kg

Q8 : 4.20cm

Q9 : 1.still A. Some fun experiments made for that one a few years back

Q10 : less than 5cm if the drawing's scale is correct (could be calculated if the areas are known)

• ## Chapter 1

Both trains are running towards each other, so you have to add both of their speeds to have the total speed that covers the 140 km.

280 km/h to cover 140 km = 30 min left before collision.

Now if he runs at 14km/h, he will cover 7km in that time. The switch is closer than that, so yes he will succeed but just barely.