Question

Shyam, a student of class -9 goes to his school at distance of 4km through an automobile fitted with a device that indicates the distance covered by him. After the school he returns to home with the same vehicle. It takes 25min to reach the school and 35min to return back.
Calculate
a. Distance travelled by Shyam.

b. Displacement

c. Average speed in the whole journey.​

Answer 1

AnswEr :

⠀x⎯⎯⎯⎯⎯ 4km⎯⎯⎯⎯⎯ y

⠀|━━━━━━━━━━━━━━━━━━|

Here,

• X is the home of Shyam.
• Y is the school of Shyam.

As per the provided information in the given question, it has been stated that the the distance from Shyam's home to his school is 4 km. In addition, it has been stated that he takes 25 min to reach the school and 35 min to return back.

We have been asked to calculate distance travelled, displacement and the average speed.

Distance travelled :

Shyam goes from his home to school and then again comes back from school to home. That means,

$\longrightarrow\tt { Distance = XY + YX} \\ \\ \longrightarrow\tt { Distance = (4 + 4) \; km} \\ \\\longrightarrow \underline{\boxed{\tt { Distance = 8 \; km}} } \; \red{\bigstar}$

Therefore, distance travelled by him is 8 km.

Displacement :

Displacement is the shortest distance from the body's initial to final position. Here, the body's initial position is x and the final position is y. Shyam goes from his home to school and then again comes back from school to home. Considering this, he again comes back to x. Thus, his initial and final position is same. So, the displacement will be 0.

$\longrightarrow \underline{\boxed{\tt { Displacement = 0 \; km}} } \; \red{\bigstar}$

Average speed :

Average speed refers to the total distance covered by the body divided by total taken by it.

$\longrightarrow \boxed{\tt { Speed_{(Avg)} = \dfrac{Total \; distance}{Total \; time} } }\\ \\ \longrightarrow\tt { Speed_{(Avg)} = \dfrac{8 \; km}{(25 + 35) \; min} } \\ \\ \longrightarrow\tt { Speed_{(Avg)} = \dfrac{8 \; km}{60 \; min} } \\ \\ \longrightarrow\tt { Speed_{(Avg)} = \dfrac{8 \; km}{1 \; hour} } \\ \\ \longrightarrow \underline{\boxed{\tt { Speed_{(Avg)} = 8 \; kmh^{-1} }} } \; \red{\bigstar}$

Therefore, average speed is 8 km/h.