Question

58. A boy walks from his classroom to the bookshop along a straight corridor towards North. He covers a
distance of 20 m in 25 seconds to reach the bookshop. After buying a book, he travels the same distance in
the same time to reach back in the classroom. Find (a) average speed, and (b) average velocity, of the boy.

please help me to answer this question​

Answer 1

GiveN :

• Distance travelled by boy from his classroom to bookshop = 20 m
• Time taken by boy = 25 seconds.

To FinD :

• Average Speed of boy
• Average velocity of the boy

Solution :

We are given that a boy starts walking from his classroom to bookshop shop which is 20 m in 25 seconds.

⇒Total distance = 20 + 20 = 40 m

⇒Total time taken = 25 + 25 = 50 seconds

Because boy moves from classroom to bookshop and also returns with same path in same time.

⇒Speed = Distance/Time

⇒Speed = 40/50

⇒Speed = 4/5

⇒Speed = 0.8

∴ Speed of boy is 0.8 m/s

___________________________

As the boy walk to bookshop and returns to classroom. So, his displacement will be 0 m

⇒Velocity = Displacement/Time

⇒Velocity = 0/25

⇒Velocity = 0

∴ Velocity of boy is 0 m/s

Answer 2

$\large{\red{\bold{\underline{\underline{Answer}}}}}$

$\purple{\sf{\mapsto Average\:speed=0.8\:m/s}}\\ \\\purple{\sf{\mapsto Average\: velocity=0}}$

$\bold{\green{\underline{Given}}} \\ \\ \sf{\rightsquigarrow Distance\: traveled = 20\: m} \\ \\ \sf{\rightsquigarrow Time \: taken = 25\: s } \\ \\ \bold{\blue{\underline{To \: Find}}} \\ \\ \sf{\rightsquigarrow Average \: speed =\:?}\\ \\ \sf{\rightsquigarrow Average \: velocity =\:?}$

❏ According To Given Question

$\\ \sf{a)} \: Average \: speed = \frac{Total \:distance}{Total \: time} \\ \\ \sf{: \implies Average \: speed = \frac{2(20)}{2(25)} } \\ \\ \sf{ : \implies Average \: speed = \frac{40}{50} } \\ \\ \sf{ \purple{ : \implies \underline{ \boxed{ \sf{ Average \: speed =0.8 \: m/s}}}}} \\ \\ \sf{b) \: Average \: velocity = \frac{Total \: displacement}{Total \: time} } \\ \\ \sf{ : \implies Average \: velocity = \frac{0}{2(25)} } \\ \\ \sf{ : \implies Average \: velocity = \frac{0}{50} } \\ \\ \sf{ \purple{ : \implies \underline{ \boxed{ \sf{Average \: velocity =0 }}}}}$