Question

Dave kunst is the first person verified to have completely circled the entire earth on his foot which is 23,255km,in 4 years.let us assume he travelled in a perfect circle around the earth. now he digs a tunnel through the center of the earth penetrating to the other side of the earth. how much time approximately will it take for him to go to the other side and come back on foot?(assume he is in a constant speed)
PHYSICS

Answer 1

let D be the diameter of earth

The distance covered will be the perimeter of circle

d= π

Time taken = 4 years.

From definition of speed

v=d/t

v= πD/t.........eq 1

If he travelled across the tunnel he would cover a distance equal to the diameter of earth

So new distance is d1= D

let time be t1

It is given that the speed of man in both the cases is same hence again using the definition of speed

v =d1 /t1

v =D /t1.........eq2

Equating eq 1 and eq 2 we get

πD/t = D / t

t1= t/π

t1= 4/π

So, ans = t1= 1.27 years

Answer 2

Answer:

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