Suppose a Car/Van is launched into space with you. Suppose you would like to do 'Surf' on the car roof like Marty in "Teen Wolf". On the earth, if car accelerate up to 30-50 or 100 mph will make Marty fall down because of air friction and because Marty is not "anchored" to the Van.

But what happen in empty space if car accelerate and I'm not anchored to the car roof ?

Will I get "car motion/speed" just because I'm lean on car roof ?

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    $\begingroup$ How does an answer get positive votes for a question that gets negative votes? I generally figure that if a question stimulates an up-voted answer, then the question must have been worth something and should get a vote as well. $\endgroup$
    – Greg
    Jun 1 '20 at 20:44
  • $\begingroup$ Technically capsules like Dragon car surf on their boosters until they reach orbit $\endgroup$ Jun 1 '20 at 21:34
  • $\begingroup$ Marty will not fall off because of air friction, but because of inertia. Same if he would be in the car and he'd not be have his belt on ... His death upon braking would hardly be due to air friction then. $\endgroup$ Jun 1 '20 at 21:51
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    $\begingroup$ @Greg The criteria for upvoting are different for questions and answers. For questions, they include "question shows research effort". A question without even basic research isn't worth being rewarded by an upvote, but its answers may still be useful. $\endgroup$
    – TooTea
    Jun 2 '20 at 9:53
  • $\begingroup$ What does "in empty space" mean? In vacuum? In free-fall? Both? (probably both, right?) $\endgroup$ Jun 2 '20 at 14:53

With no gravity there is no friction between shoes and the car roof. You'll keep floating as you were while the car will speed away... if it gets any traction between the wheels and whatever it drives on, which would be absent just the same. But maybe it has a rocket engine.

On the other hand, if you stand "sideways" on the car grill or windshield, the car's acceleration will substitute for gravity and you'll be accelerating with it... for as long as the car keeps accelerating. As soon as it cuts off into neutral, the compression force that squeezed the soles of your shoes between the car and your feet will rebound and send you flying ahead.

  • $\begingroup$ What does As soon as it cuts off into neutral mean? $\endgroup$
    – gerrit
    Jun 2 '20 at 8:43
  • $\begingroup$ @gerrit stops accelerating. $\endgroup$
    – SF.
    Jun 2 '20 at 9:09
  • $\begingroup$ Why would I be sent "flying ahead" when the car stops accelerating? We'd both be in exactly the same orbit with the same forces acting on us, so unless I push myself away from the car, I shouldn't accelerate relative to it, should I? $\endgroup$
    – gerrit
    Jun 2 '20 at 9:23
  • $\begingroup$ So you're telling me that speak about "lean on other object" in no gravity / Space doesnt' mean nothing, because of gravity 0 .. $\endgroup$
    – stighy
    Jun 2 '20 at 9:25
  • $\begingroup$ @gerrit "the compression force that squeezed the soles of your shoes between the car and your feet will rebound" - anything missing there? Rubber soles? $\endgroup$
    – SF.
    Jun 2 '20 at 9:28

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