### The Physics Philes, lesson 90: Don’t Cross the Streams!

So far in our discussion of fluid mechanics we’ve been dealing with properties of fluids when those fluids are at rest. I think we have that pretty much mastered, so it’s time to move on to something a little more complex: fluid in motion, aka fluid flow! Fluid flow is …

Physics

### The Physics Philes, lesson 89: Sink or Swim

OK, class. Let’s talk a little more about fluid mechanics. You’re probably already pretty familiar with buoyancy. It’s why you float in water and why helium balloons float in the air. Those things are just a physical manifestation of something called Archimedes’s Principle: When a body is completely or partially …

### The Physics Philes, lesson 66: Walk the Plank!

As promised last week, I’m back with a sample problem dealing with a body’s center of gravity! So let’s dive right in, shall we? Let’s say you have a wooden plank that is 6.0 m long and weighs 90 kg. You set the plank of wood on top of two …

### The Physics Philes, lesson 60: Momentum, It’s Not Just for Lines Anymore!

This will be a relatively quick post this week because of…laziness. But still! Physics! Today, we start a more in depth discussion of angular momentum. Before we get too deep, we need to start shallow. Let’s wade in. A loooooong time ago, we had a little discussion on momentum. The …

### The Physics Philes, lesson 59: Work and Power, Torque Style

I’ve been rambling on and on for the last several weeks about rotational and translational motion. This week we’re…not changing the subject, exactly. Instead, it’s time to bring the concepts of work and power into the mix. In real life, we can do work on a rotating object. Like when …

### The Physics Philes, lesson 54: Axis in Motion

So far in my studies of rotational motion, I’ve focused on rotating rigid bodies where the axis of rotation is stationary. But what about when the axis of rotation is actually moving? What then? Well all your questions will be answered in the coming weeks. I should probably first establish …

### The Physics Philes, lesson 53: Even More on Rotational Dynamics

I’m back, once again, just in time to serve you your weekly dose of physics. As promised last week, I’ll walk you through a problem that will illuminate the rotational dynamics of rigid bodies. Well, I’ll try to anyway. Let’s say we have a cable wrapped around a uniform solid …

### The Physics Philes, lesson 51: Pipe Dreams

Last week we started discussing a brand-spanking-new topic: torque! At the end of last week’s saga, I left you with several different methods of calculating torque. This week I’ll do my best to show you how those equations work. Are you ready to go? LET’S DO IT. We have a …