What is the minimal speed with which a person can run on the surface of the water.???????????????????????



This question appears in the "Problems in Physics" by P.L. Kapitza

if we assume water can provide no normal support to us (means it is like air ...a fluid)...i think the minimum speed will be such that the person running behaves like a satellite of the earth....so he goes into orbit arnd the earth at water level...
the answer sounds very stupid but that's all i can think of rite now....

so, your assumption is wrong..

lolz.. nice.. but premsharma there exists a lizard which can actually run n water i think its the gecko lizard(i m not sure..) so the question holds and what u gotta take into account is the time period for which the surface tension holds and calculate

hi a gud ques actually one needs to think before answering it
it is da BASILIK LIZARD as said above but here da ques is for da case of human beings.actually with each step a person must ,firstly, slap its foot against da water& den push it down into da water to form an air cavity around da top of da foot.to avoid having da pull, da foot must b dragged back up against water drag in order to complete da step ,den da man shud withdraw da foot before water can flow into da air cavity.during dis full action of slap ,downward push ,& withdrawal,da avg impulse on da man must match da downward impulse due to da gravitational force if da man is not to sink .(dis is what exactly a lizard do as far as i know)so for solution ,assumption of no normal contact force rules out ,n debu i want u to reply if i m thinking correctly(if u have got da ans of dis ques)so what i think is dat da backward dragging force will control da speed of da man.

picz..ur ans is quiet logical..obviously bettr dan d previous ans.but...........seriously even i don't know d .......exact ans.......but i think u r in d rite direction..even i was thinking d same..... ..lets discuss it in d class..............