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A dog of mass 5Kg is standing on a flat boat so that he is 10m from the shore.He walks 4m on the boat towards the shore and then halts. If the mass of the boat is 20Kg, find the distance of the dog from the shore when it halts________

6 years ago


Answers : (1)


Dear sindhuja

let the x1 is the distance of center of mass of boat from the shore,and Xc.m is the distance of  center of mass of the system from the shore

Xc.m =(5*10 +20*x1)/(20+5)

          =2 +(4/5)  x1

now let boat move x distance away from the shore when dog move 4m towards the shore

so new distance of boat from shore=x1 +x

new distance of dog from shore=10-4 +x=6+x


 Xc.m ={5*(6+x) +20*(x1+x)}/(20+5)

          =(30+25x +20x1)/25

          =6/5 +x +4/5x1


equate both Xc.m

6/5 +x +4/5x1 =2 +(4/5)  x1



so distance =6+4/5


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6 years ago

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