Rotational Mechanics 2

"R" You Good at Vocab?

2

The shortest distance between the center of a circle to one of its edges. 

Radius

4

Instead of angular dynamics, we also use this term to describe spinning kinematics. 

Rotational

6

The word we use for how many times a disk went around- one whole spin is one of these. 

Revolution

8

We most often convert revolutions to this unit, which always has a pi term. 

Radians

10

This is the tendency of an object to resists changes in how fast it is spinning. 

Rotational Inertia

Put Some Spin on It!

2

Δx

Δθ

4

v

ω

6

a

α (I know they look similar. That is alpha.)

8

F

ꚍ

10

m

I

Moment of Inertia Calculations

2

An object whose mass is entirely distributed throughout the axis of rotation

No moment of inertia (0)

4

An ideal 10m long string is held at one end and is spinning a 1kg mass at its other end

100 kg m²

6

A massless 10m long stick is held at its center and is spinning a 1kg mass at both ends

50 kg m²

8

A solid cylinder with a mass of 2kg and a radius of 2m spins about its cylindrical axis

4 kg m²

10

A massless 20m long stick is held at its center and is spinning. It has 5 1kg masses at every 5 m interval, including on the ends

250 kg m²

Follow the Law (or Theorem)

2

This law is why you spin faster if you bring your arms in- similarly to how if you throw mass off of a boat, it will speed up.

Law of Conservation of (Angular) Momentum

4

Torque being proportional to moment of inertia and angular acceleration is the rotational version of this law

Newton's 2nd Law

6

This theorem shows that the moment of inertia for an object is always greater when not spun about its center of mass

Parallel Axis Theorem

8

Name the two requirements for an object to be in equilibrium.

1. Must have a net force acting on it of 0.

2. Must have a net torque acting on it of 0.

10

Explain the parallel axis theorem in words

The moment of inertia for an object spinning about an axis parallel to an axis through its center of mass increases with distance between the two axes. It is proportional to the mass of the entire object and the square of that distance.

Random Trivia

2

This is the deepest point of Earth's ocean. 

The Mariana Trench

4

Mr. Trauger is seeing a symphony play music from this farming themed game next month. 

Stardew Valley

6

This Saint is known for marrying soldiers in private when it was outlawed. 

St. Valentine

8

This is how many people on average die annually from vending machines in the US. 

2-3

10

This British biologist is most famous for his voice that spans over many different nature documentaries. He achieved knighthood twice for his conservationist efforts. 

David Attenborough