Skateboarding Physics: Force of Landing from 10ft Roof

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In summary, the scenario with the most force on the skateboarders feet upon landing on the ground is when they ride the skateboard 15 mph off of a 10ft building roof.
  • #1
kevshabar Reference
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Which scenario would exert the most force on the skateboarders feet upon landing on the ground?

Scenario 1: Skateboarder rides skateboard 15 mph off of 10ft building roof
Scenario 2: Skateboarder falls directly vertical (0 mph) off of 10ft building roof

Assumptions:
-- no friction
-- maximum vertical fall distance is the same in both scenarios
-- roof and ground are level in both scenarios

UPDATE: (more assumptions)
-- board and rider remain in a horizontal (board) and upright (rider) position
-- rider lands with both feet on the board
-- board lands with all wheels coming in contact with the ground at the same time
-- rider's shock absorbing body movements are the same in both scenarios
 
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  • #2
Welcome to PF.
They will be the same, but in scenario 1, the front axle will start to fall first so axle impact with the ground will not be synchronous. The total deceleration time will be longer so the force can be less.
 
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  • #3
Sounds an awful lot like a homework problem, so why not show us your result first?

Meanwhile, there's no assumption that the guy is actually going to land feet-down. I mean, a skateboard under you is going to affect a fall since it cannot all go over the edge simultaneously.
 
  • #4
Halc said:
Sounds an awful lot like a homework problem, so why not show us your result first?

Meanwhile, there's no assumption that the guy is actually going to land feet-down. I mean, a skateboard under you is going to affect a fall since it cannot all go over the edge simultaneously.
It's actually a debate with my brothers, thanks for your concern though.
 
  • #5
The answer will be rider, style, case and assumption dependent.
If the rider lands on their head there will be little force on their feet.
What assumptions are being made?

I would expect the rider to transfer weight to the rear axle as the front axle goes over the edge, so there will be less rotation of the board. The scenario results will then be similar.

If it goes wrong, the survivability will be greater with injury reduced in scenario 1, since the rider will be better able to land and roll like a parachutist. That will transfer vertical momentum into horizontal momentum more efficiently than in scenario 2, where energy must be dissipated in a small area.
 
  • #6
@Baluncore we haven't even started debating about survivability yet.. 😂 I updated the original post with some more assumptions
 
  • #7
Welcome to PF. :smile:

kevshabar Reference said:
It's actually a debate with my brothers, thanks for your concern though.
We need to know if it's schoolwork so we can be sure to keep such posts in the dedicated schoolwork forums. Hence the question. Thanks for your reply.

kevshabar Reference said:
@Baluncore we haven't even started debating about survivability yet.. 😂 I updated the original post with some more assumptions
I hope you and your freinds are not contemplating trying this on a dare or bet or something. My teenage son did something almost similar from about 7 feet, and ended up with casts on both arms for a while (not a good scenario, for multiple reasons that was a very bad result).

I've flat-landed my MX dirtbikes from maybe 7-8 feet high a few times, and flat-landers are always uncomfortable. Much better to land on a down-slope, from no matter how high. :wink:

BTW, please try not to update your previous posts with new information -- that can be very confusing for otheres who are responding. Please instead just post a new reply. Thanks.
 
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  • #8
There can be no difference between the two scenarios if the goalposts are assumed to be in the same hole.
 
  • #9
They should be the same because the x and y components are independent of each other and the force of the feet on the ground is in the y direction. The x component of the skateboarder riding 15 mph (x component) would not affect the y component.
 
  • #10
annamal said:
They should be the same because the x and y components are independent of each other and the force of the feet on the ground is in the y direction. The x component of the skateboarder riding 15 mph (x component) would not affect the y component.
The force is almost certainly greater in the second case, as you have horizontal as well as vertical deceleration on landing.
 
  • #11
PeroK said:
The force is almost certainly greater in the second case, as you have horizontal as well as vertical deceleration on landing.
But there is no friction, so cannot decelerate horizontally.
 
  • #12
Baluncore said:
But there is no friction, so cannot decelerate horizontally.
There will be, once the skateboard shoots out from under and the posterior hits the sidewalk. [But OP specifically mentions "skateboarder's feet"]
 
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  • #13
jbriggs444 said:
There will be, once the skateboard shoots out from under and the posterior hits the sidewalk. [But OP specifically mentions "skateboarder's feet"]
The OP post #1 assumptions were extended.
Assumptions:
-- no friction
-- maximum vertical fall distance is the same in both scenarios
-- roof and ground are level in both scenarios
(more assumptions)
-- board and rider remain in a horizontal (board) and upright (rider) position
-- rider lands with both feet on the board
-- board lands with all wheels coming in contact with the ground at the same time
-- rider's shock absorbing body movements are the same in both scenarios
 

FAQ: Skateboarding Physics: Force of Landing from 10ft Roof

1. What is the force of impact when landing from a 10ft roof while skateboarding?

The force of impact when landing from a 10ft roof while skateboarding depends on several factors such as the weight of the skateboarder, the speed at which they are traveling, and the angle at which they land. However, on average, the force of impact can range from 4,000 to 8,000 pounds.

2. How does the force of landing from a 10ft roof affect the skateboarder's body?

The force of landing from a 10ft roof can have a significant impact on the skateboarder's body. It can cause injuries such as bruises, sprains, and fractures. In extreme cases, it can also lead to more serious injuries such as concussions or broken bones.

3. What role does gravity play in the force of landing from a 10ft roof while skateboarding?

Gravity plays a crucial role in the force of landing from a 10ft roof while skateboarding. As the skateboarder falls from the roof, they are pulled towards the ground by the force of gravity, which increases their speed and the force of impact upon landing.

4. How can skateboarders minimize the force of landing from a 10ft roof?

Skateboarders can minimize the force of landing from a 10ft roof by practicing proper techniques such as bending their knees upon impact, distributing their weight evenly, and rolling with the momentum. Wearing protective gear, such as helmets and pads, can also help reduce the force of impact.

5. Are there any other factors besides force that skateboarders should consider when landing from a 10ft roof?

Yes, besides force, skateboarders should also consider the surface they are landing on, the condition of their skateboard, and their own physical abilities. Landing on a smooth and flat surface can help reduce the force of impact, while a damaged skateboard or fatigue can increase the risk of injury upon landing.

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