Question
Question: Four persons K, L, M and N are initially at rest at four corners of a square of side d. Each person ...
Four persons K, L, M and N are initially at rest at four corners of a square of side d. Each person now moves with a uniform speed v in such a way that K always moves directly towards L, L directly towards M, M directly towards N and N directly towards K. Show that the four persons will meet at time t =
A
4d/v
B
3d/v
C
2d/v
D
d/v
Answer
d/v
Explanation
Solution
Initial distance between any two person = d
Considering KL,
Velocity component of L along LK,
v cos 900 = 0
Thus speed between K and L is v
∴ time t = d/v.