the frictional torque =2umgr/3 not 2/3umg
maybe a typing mistake by elastiboysai!!

the method is absolutely correct

 

both the answers r coming using simple eq of rotational motion.........so whats the prob????????

 

hey wait a minute............i am correct!!!!!!!!

i dont mean a monkey will choose his master but a monkey can have his master in m ways(since there are m masters)
hence my ans

plz check ur ans!!

in the ques each monkey has to have a master not every master to have a monkey

 

so we have to see frm the monkey's perspective

 

anyways the reverse cant bring the correct ans since when one master has chosen a monkey then n-1 monkeys are left for others

 

hence the ans n^m can never come!!!!

m^n
since each monkey can choose his master in m ways

m *m*m*m..........ntimes

=m^n

let coordinates be (x,y)

focus =(1,0)

focal dis=(x-1)²+y²

putting y²=4x

 

d^2 =(x-1)²+4x

36=x²+2x+1

solving

x=5 or -7

since -7 does not lie on the parabola

so x=5

y=20=+-2root5

 

so (a) and (b) 

it will reach ground with same vel and angle with which it was projected

 

since vel in hor direc remains same so no change in momentum

in vertical direc initialmomentum =-psin theta(opp to direc of final momentum)

final momentum =psintheta
 change in momentum =2psin theta