Question

Question 12
boy goes from A to B with a velocity of 20 m/min and comes back from B to A with a velocity of
30 m/min. The average velocity of the boy during the whole journey is
(a) 24 m/min
(b) 25 m/s
(c) Zero
(d) 20 m/min​

Answer 1

Option (c) Zero is the correct answer.

Explanation :

$\small{ \pink{ \boxed{\boxed{\begin{array}{cc} \maltese\:\bf\:Page-\:1:\:\maltese\\\\\maltese \bf \: we \: know \: that \\ \sf \: Displacement \: is \: the \: length \: between \\ \sf \: the initial \sf \: and final \: point \: of \: the \: path \\ \sf \: \: which \: is \: travelled. \: \\ \\ \bf\:and\\\\</p><p> \odot \blue{ \boxed {\sf \: Average \: velocity \: \bar{v}</p><p> = \frac{total \: displacement}{total \: time} } }\\ \\ \sf \: In \: this \: case \: the \: initial \: point \\ \sf\: and \: the \: final \: point \: is \: the \: same \: which \\ \sf \: is \: A \: ( Since \: it \: goes \: from \: A \: to \: B \: then \\ \sf \: returns \: to \: A) \\ \: \\ </p><p> \bf \: Hence \: the \: \blue{ \sf \: net \: displacement \: is \: \: = 0 }\\ \\ </p><p></p><p> \sf \: Now \: if \: you \: put \: it \: in \: the \\ \sf \: formula \: the \: average \: velocity \: comes \\ \sf \: out \: to \: be \: \: = 0. \\ \\ \orange{ \bf \therefore \: average \: \: velocity \: \bar{v} = 0} \\ \\ </p><p></p><p> \\ \underline{ \sf \: Note:} \sf \: The \: velocity \: from \: A \\ \sf\: to \: B \: and \: from \: B \: to \: A \: does \\ \sf\: not \: matter \: since \: the \: displacement \\ \sf \: is \: 0 \: and \: it \: is \: given \: only \: to \: confuse \: \\ \sf the \: one \: who \: is \: solving. \\ \: </p><p></p><p>\: \end{array}}}}}$