Blueprint Excerpts, Case 3: Rush is a Good Boy
Welcome back to another edition of Blueprint Excerpts, a segment where we speculate on how some of the robots of the Mega Man series work. We don't just have to talk about Robot Matsers here, so today, we are gonna talk about Mega Man's robotic companion, Rush. Rush has sported a lot of abilities over the years, but his most iconic just might be Rush Coil. Today, we ask ourselves, how strong is Rush Coil?
Rush Coil uses a compressed spring to shoot Mega Man up, and fortunately, the equations to model a spring are fairly simple! The Force and Potential Energy are given respectively by:
F(s) = -kx
PE(s) = .5kx^2
So F(s) = -2PE(s)/x
Where x is the distance the spring is compressed and k is called the spring constant, a physical property that usually is experimentally found. In the posts up until now, we have used some idea of the net force being zero, ie, the Robot in question was not experiencing acceleration. But that clearly is not the case here; Mega Man gets sent flying before gravity slows him down and pulls him back down. Instead, we are going to be using some idea of energy conservation. After all, once Mega Man is no longer is touching that spring, he's got nothing but Kinetic Energy, which is given by:
KE = .5mv^2 = PE(s) = .5kx^2
So F(s) = -2PE(s)/x = -2KE/x = -mv^2/x
Recall that Mega Man's mass is 105 kg, and x, the amount Rush Coil's spring is compressed, can be measured to be about 55/150 of his height, which is listed to be .65 meters, so that comes out to be .238 meters.
To find velocity, we could try to measure his speed frame by frame (as we did in the last post), but here, we are gonna use another shortcut. Imagine that, rather than Rush Coil boosting Mega Man to some height where his velocity becomes 0 (as his upwards movement changes to downwards movement), we consider when he falls downwards from the apex of his jump, gaining some speed due to gravity. It takes 25 frames to reach that apex, and at the point, it was the same speed Rush launched him upwards, just opposite in direction. So his speed leaving Rush Coil must be:
v = 25/60 * 9.81 = 4.09 m/s
So F(s) = -mv^2/x = -(105)*(4.09)^2/*(.238) = 7361 newtons.
And let me tell you, that is pretty strong. It's a good thing Mega Man is a robot, cause that is MORE than enough to break some bones, if not kill you. Now, this was a shorter post, so I want to addressthe elephant in the room; this 80s retro video game's physics make no sense. If we had calculated this another way, we would have to conclude that the acceleration of gravity on Mega Man's earth is much different than our own, despit the worlds seeming identical. Maybe we can talk about that some other time.
Rush Coil (ラッシュコイル, Rasshu Koiru) is a recurring item in the original Mega Man series. When used, Rush appears and a coil platform emerges f
"No, you're wrong! I only fight when I am forced to protect the world from those who would pit machines against man. I believe humans and ro
Written by: Tobyjoey