Calculating the Force and Power to Split Wood

Rhett Allain
6 min readJul 20, 2024
Photo: Rhett Allain. Illustration of Thoren splitting wood.

Thoren Bradley keeps popping up on my video feeds. I don’t know why, but whenever I see a video with Thoren, I can’t stop watching. Yes, he’s just splitting wood. What’s the big deal? I seriously don’t know. Check it out.

But perhaps you know what I do. When I see something fun, I have to add some physics to it. In this case, I want to use the video above to estimate both the impact force during the collision with the wood AND the average power of Thoren as he swings this 8 lb maul. It’s going to be fun.

Force and Momentum

Let’s start with the physics. There’s a bunch of great physics that happens when the head of the maul hits the wood. First, there’s the momentum principle. This says that the net force on an object changes its momentum. Oh, but what is momentum? It’s a way that we can mathematically describe the motion of an object. We define it as the product of the object’s mass and its velocity.

Yes, we represent momentum with the vector p. It’s fine — we already use m for mass. If we look at the motion of the…

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Rhett Allain
Rhett Allain

Written by Rhett Allain

Physics faculty, science blogger of all things geek. Technical Consultant for CBS MacGyver and MythBusters. WIRED blogger.

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