1its (B)
While walking on the ice we take short steps.....as short steps provides:-
a)Larger Friction b)Smaller Friction c)Larger Normal force d) Smaller Normal Force
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16 Answers
1its A..long steps provide small friction...and so we tend to fall in between two steps..........however taking shorter steps help toprovide sufficient friction to prevent slipping in btwn two steps...
1as ice is very slippery ( friction coeff is negligible) we need some friction so that we dont slip and fall...so probably its (A)
1my thought process:
normal force will be same whether u take large steps or small steps
now when u walk u feet(grounded) tends to push back the surface and thus static friction comes into play
if u happen to take large steps the time of application of force is longer thus the surface of ice unsettles(heat and all)which causes slipping
so basically small steps reduce the time of application of frictional force on ice
f=uN [N is normal force which is fairly constant in the process if u ignore the shortening of height thereby downward acceleration of man while he lifts his feet]
u=coefficient of friction depends on nature of bonding(interlocking)
if time taken for each step is more then u increases(as the surface is not stable) and slipping takes place
thus we take small steps
1Excuse me....but exactly how can you write "time taken for each step is more than u"? How can magnitudes of two different physical quantities be compared?
How about this?→
When long steps are taken, angle(a) between your legs and the ground is more. Hence, the horizontal component of the normal force(F) applied is greater than the horizontal component of the normal force applied in shorter steps(since here the angle is less.) Hence, for greater horizontal component, slipping is more. So we take shorter steps. Actually, here you need to think ulta, and that it is less friction for less HORIZONTAL component of normal force. Hence the answer is (b).
[remember sine is an increasing function in (0,90°), hence value of sine greater for greater angle.]
Acceptable answer? :D
1what?
did i just read horizontal component of normal force?...lol
dude the normal force is always perpendicular to the surfaces in contact
and i guess i have explained how u increases with time....
seriously which book tells u about horizontal component of normal force?
1if u need any solution to hc verma problems for part 1 here is the entire solution book download link...
http://www.4shared.com/document/I3UPo3tY/Solution_to_HC_Verma_Part_1.html
1Ans> b as we lake short steps our foot makes an angle which is greater than the angle formed by the leg when we take long steps with the horizontal hence the Frictional force f will have to overcome a force that is mgcosθ which wil be less but the limiting friction in this case mgsinθ be more hence whatever the coefficient of friction is we will get less friction with short steps.
1acc. to me,,this question can be xplained using the concept of torque..
when we take long steps..the distance b/w our legs increases...
thus..conceptually..torque = F x d
here F would be the normal force..as the distance is more b/w the legs the value of torque increases!
simple..more chances of falling with its increase :D
i think that'l sove it..still i dun have any idea about the options you gave..
1and when we take short steps...the value decreases...nd more of..that equilibrium thing is there..
1Here actually the answer can be a or c....but v need more friction 4 nt slipping....but more friction wil b a result of more normal force as "u" is constant here.....so the answer must b c bcoz v r generating more friction by applyin more normal force....