VELOCITY OF STONE RESPECT TO BELT=Vsb=9  

           thus Vs-Vb=9  

                                    

and Vb=4

 

so Vs=13

 

now VELOCITY OF STONE RISPECT TO MAN ON GROUND=Vsm

hereVm=0

so from Vs-Vm=13-0=13

soVsm=13

 

 

z1,z2,z3 are the vertices of eqilater tringle and z0 is the circumcenter of that tringle then

z1^2+z2^2+z3^2-3z0^2=0 slove

de moivre's thyorem is

if [cos@+isin@]^n then =cosn@+insin@

i have given the answer

i am giving the secondone answer.

they are types of geometrical isomerism in alkene.

in cis isomeram same atom or fuctional group which is conected with the carban atom are in same direction.and in trance they are inopposite direction from each other. 

for 5kg block suppose it move"s downword

acc of 5kg blo & 4kg blocksare a1&a2

5g-2t=5a1______ 1

now for 4kg block

t-4g=4a2 

t=4a2+4g______2

from constraint eqn

2a1=a2______3

 

now we put value of t in 1

so   5g-2(4a2+4g)=5a1

5g-8a2-8g=5a1

-3g-8a2=5a1

-3g-16a1=5a1       from 3

a1=-3g/21

a1=-g/7            nagative shows that it(5kg block) wiill moves upward

and a2=2g/14