1does no one think that as the rat moves the wooden mass will also move
as nothing is said about friction
Forgive me if I am blabbering[2]
but in that case plz explain when do we do such kinds of things in questions
a strip of wood of mass M and length l is placed on a horizontal ground A rat of mass m starts from one end of the strip and reaches the other end in time t1 It then jumps off vertically The strip moves a further distance l in time t2 then
a)t1=t2
b)t1<t2
c)t1>t2
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10 Answers
62when the rat jumps of vertically his velocity in the horizontal direction is zero.. the mass was on the rest initially so the linear momentum was zero...
So when the rat jumps off the linear velocity of the wood strip is also zero.....
So t2 willl be infinite....
Did i read the question right?
1
13well, nothing can be concluded from d given situation... particularly the phrase "jumps off vertically" leads to many confusions... i think d question needs more clarity...!!!
if not... then, from general interpretation, v can conserve kinetic energy of d rat n d plank...
=> 1/2 . m(l/t1)2 = 1/2 . M.v2
=> v = (l/t1)√(m/M)
hence the time required to travel a distance of l units = t2 = l/v = t1.√(M/m)
since M>m, hence t2>t1...
well, i'm not sure of my solution... i would be glad if anyone point out my mistake(if any)...
1maq if the wood moves the rat will not move a distanc of l i think??!!
62damn i am waiting for philip's answer....
i had to uncolor my post :(
1[11]what happened !! [11]
i didn't solve coz i think the answer would be B
see
if the strip moves backward then it will cover a distance < l
so i thought the answer would be B in any case (more particularly if there is no or "less" friction beneath
edited [1]
now coz there is nothing much given in the question we should also not give much in the answer
in case the wood of block moves the friction blow is zero or insufficient that should explain it i think!!
13The problem starts when d rat jumps off vertically from d planck... so i think its not necessary to discuss d relative motion of d planck n rat before it jumps off... what say...!!!