This is related to the “airplane on a treadmill” myth (go watch).
Preservation of momentum
I wanna say it’s incorrect, but really I’ll say it’s exaggerated. The man on the diving board is going to continue moving forwards just like the rest of the gear, he’s not going to suddenly stop on relation to the road surface. However, he is going to be affected by wind resistance (which scales exponentially with speed) so he will need to make a good forward leap in order to not fall behind because of that. If he doesn’t, he would be effective jumping backwards - but not as far as depicted (unless the car is travelling really, really fast).
If the pool (and indeed, the man) were encased within an envelope to protect from that wind resistance, he would be entirely unaffected. So there.
Unless the driver tosses it in neutral, the engine is also still doing work even if keeping the car’s speed constant whereas when the diver jumps, I think he stops being a part of that system he will slow down compared to the van, right? How much this affects the landing of the jump depends upon speed, wind speed, etc.
This is related to the “airplane on a treadmill” myth (go watch).
Preservation of momentum
I wanna say it’s incorrect, but really I’ll say it’s exaggerated. The man on the diving board is going to continue moving forwards just like the rest of the gear, he’s not going to suddenly stop on relation to the road surface. However, he is going to be affected by wind resistance (which scales exponentially with speed) so he will need to make a good forward leap in order to not fall behind because of that. If he doesn’t, he would be effective jumping backwards - but not as far as depicted (unless the car is travelling really, really fast).
If the pool (and indeed, the man) were encased within an envelope to protect from that wind resistance, he would be entirely unaffected. So there.
It’s not just how fast the car is going. How high the diver jumps (how long he’s in the air) also factors in.
Unless the driver tosses it in neutral, the engine is also still doing work even if keeping the car’s speed constant whereas when the diver jumps, I think he stops being a part of that system he will slow down compared to the van, right? How much this affects the landing of the jump depends upon speed, wind speed, etc.
Drag scales quadratically with speed, not exponentially.