Estimate the acceleration you subject yourself to if you walk into a brick wall at a normal walking speed.?

Question

Estimate the acceleration you subject yourself to if you walk into a brick wall at a normal walking speed. (Make a reasonable estimate of your speed and of the time it takes you to come to a stop, and explain those numbers also.)

Answer 1

Well, generally speaking, it depends on how fast you're walking -- since, relative to you, the brick wall is an immovable object (okay, so it plastically deforms ever so infinitessimally upon impact, but COME ON...), you experience an inelastic collision, and come to a complete stop in more-or-less the same amount of time (there may be a few nanoseconds difference if you run into the wall at 3 mph as opposed to a brisk 3.5 mph, but it's negligible in a time scale that you'd notice) So let's say the average walking speed is 3 mph (for simplicity), and you come to a stop in approximately 0.1 seconds. Let's put acceleration in terms of feet/sec/sec, so 3 mph X 5280 feet/3600 sec/hr / 0.1 seconds = about 44 feet/sec/sec acceleration in the opposite direction. Moving at a faster speed, you will experience that much more acceleration back the way you came, but because you are softer than the wall, the inelastic collision will probably cause you to bounce back off the wall, changing the actual experienced acceleration you feel. Really, hard to answer without more assumptions.

Answer 2

if i were walking toward a brick wall, i would not accelerate.