Cycling Equipment · Public discussion

Re: Physics - biking question

Started by Dan · · Last activity · 2 posts · 314 views

Thread details

What we know about this thread

Original section
Cycling Equipment
Published
3 October 2004
Last activity
3 October 2004
Original author
Dan
Posts
2
Discussion status
Public discussion
Total views
314
Views / 30 days
0

The navigation and discussion metadata provide context. Posts remain in their original chronological order.

Showing posts 1–2 of 2
Posts remain in their original chronological order.

Text size
  1. You need to think of an energy solution. At 10 mph you have stored up
    one-half-mass-times-velocity-squared (.5MV^2) dynamic energy. In the crash
    this energy is used up in deforming materials, making sound, producing heat
    and the post impact velocity. There is also the force-times-distance (Fd)
    energy which is what you are referring to.

    Lets make it easy, assume that you and the bike are a rigid body, the impact
    brings you to a complete stop and ignore all losses except (Fd). Mass is
    weight/gravity and 1 mph = 1.47 mph. Then:

    ..5MV^2 = Fd
    ..5(150/32.2)(10)^2(1.467)^2 = Fd

    Or:
    Fd = 503 ft-lb

    It takes a 503 lb force to stop in one foot (ouch!)
    Braking at .6g, F = .6(150) = 90 lbs and d = 10 ft

    In an impact you can use a conservation of momentum solution as well.


  2. Quoted message said:

    It takes a 503 lb force to stop in one foot (ouch!)
    Braking at .6g, F = .6(150) = 90 lbs and d = 10 ft

    Ooops! Make that d = 503/90 = 5.6 ft

Active in the last 60 minutes

Active in this thread

0 users · 0 guests ·0 bots ·0 total

No signed-in users are active right now.

No known search crawlers active right now.