# (Econ) You Don't Appreciate Me! (Pt 3)

{BACKGROUND / HINT: We went over the Straight-line method of depreciation, as well as the MACRS method.}

You've done it. You've finally met your goal of securing a consistent revenue (say X amount) for your company every year for the foreseeable future. You're in the rubber-band business. And surprisingly, the revenue stream is quite predictable. Once a retailer buys from you, it's for life.

However, it's also time you replace your rubber-mixing vats. You've got hundreds of them. So you know it's going to be costly... But it's OK since you plan on using the life out of these vats till they fall apart. And at least that will be a nice tax write-off!

Filling out the tax sheets, you realize you've got 2 options: You can "depreciate" your new vats according to the Straight-Line method or the MACRS methodLike any responsible business-owner, you want to minimize your taxes and ensure the long-term health of your business. Which depreciation method should you choose?

### Josin Sang

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# (Physics) Fire the Rockets!

(Original question contributed by Professor Autar Kaw; modified with permission)

Have you ever wanted to be the smartest person there is? Well then, you may want to be a rocket scientist!

You a running rocketry test using a miniature prototype. Through many measurements you figure out an equation that describes the distance covered in meters by the rocket in its current configuration:

Using this information, figure out what the acceleration of the rocket is at t=2.

### mauro perez

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# (Probability) Braaains...

You and two traveling buddies are in a local village one day feeling pretty hungry. That's when you decide to try something very different...

A vendor sells you and your buddies some sweet-smelling monkey brain. Unbeknownst to you, the monkey brain is starting to rot and you each equally have a 37% chance of being turned into a zombie.

How likely is it that someone will be trying human brains in the morning?

### mauro perez

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A great & versatile problem solver learns to look at problems a few different ways.

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# (Physics) The Drunk Chicken Balancing Act

This poor chicken got its hands on some fermented food. Now it’s inebriated! ... A gust of wind blows on it at an angle of 37° with respect to the horizontal. The horizontal distance from the claw to where the wind force is applied on the chicken is 0.7 cm.

If the wind’s feeling particularly nice that day, what force should it blow with to help this out-of-balance 2.5 kg chicken?

# (Physics) Recreating the Car Collision - Guilty of Speeding?

Another day, another collision to investigate...

You arrive at the scene of a car accident (a street intersection), and are asked to determine if any of the cars involved were speeding.

You immediately begin gathering information, and note the following:

• A sunny day, which means the accident occurred on dry concrete. Both cars have standard rubber tires. A quick glance at a reference table tells you the coefficient of kinetic friction is 0.68.
• Car #1 approached from the North. The model has a mass of 2675 kg.
• Car #2 approached from the West. The model has a mass of 1640 kg.
• The accident occurred in a 30 MPH zone.
• Witnesses say the two cars stuck together upon impact until coming to a complete stop.
• You measure a 13.9m long skid mark 66° South of East (a.k.a 294°).

So...anybody guilty of speeding here?