Everyone has them Same comment about Batman: He’s cool because he’s just a regular guy, but he’s also a superhero. It’s true, he doesn’t have superpowers. However what he did does have is a combination of skills and equipment.
In the movie The Batman, we see him using one of his “toys” – his Ascender pistol. (It’s also known as a grapple gun or grappling gun.) Batman uses it to launch something like a grappling hook connected to a cable. Once attached to a high point, an electric motor inside the gun winds up the cable and pulls Batman up.
In this scene, Batman is in a building with a group of Gotham cops who have arrested him. He doesn’t think that’s such a good idea. After breaking free, he runs to an interior stairwell and shoots the riser near the top of the stairwell and then activates the motor to pull him up. Spoilers: He escapes. (But you probably knew that.)
Now for the physics calculations: what type of battery or power source would his ascender require and how much current would it draw? Let’s start with a little background knowledge about energy.
energy for ascension
One of the key ideas for understanding energy is to define a system of interest, which is the collection of objects we want to study. (Of course, the most complete system is the entire universe, but it’s not very practical to cover it all at once. Instead, we want to isolate only the objects we’re interested in.)
Let’s use the following system: Batman plus the winch (and its battery) and the earth. (You might think Earth is a weird thing to add to the system, but just wait, we’ll get there.)
Once we have a system, we can apply one of the most important concepts in physics: the work-energy principle. This states that the work done on a system is equal to the change in energy of the system. But what the heck is energy?
That’s actually a tough question, but here’s my best answer: Energy isn’t a real thing, it’s a way of keeping track of various interactions. Energy also comes in different forms. For example, kinetic energy is related to the movement of objects, and potential energy is the kind that depends on the position of objects.
So work is a way of adding or removing energy from a system. In terms of forces, we define work as follows: