Question

Ram went to Chandigarh which is $250\,Km$ from Delhi. He started from Delhi at $6\,a.m$ and reached Chandigarh at $11\,a.m$ Find the average speed by which he travelled from Delhi to Chandigarh.

Answer 1

Hint: In physics, the fundamental unit for measuring the distance is known as meter and denoted by $m$ whereas the fundamental unit for measuring time is seconds which is denoted by sec here, we will use the definition of average speed which states that, the ratio of total distance covered by the body in total time taken is called average speed of the body and SI unit of velocity is $m{s^{ - 1}}$ which is read as meter per second.

Formula used:
The formula used for average speed is,
$Spee{d_{average}} = \dfrac{\text{Distance}}{\text{time}}$

Complete step by step answer:
According to the given question, we have given the distance between two cities from Delhi to Chandigarh, let’s say denoted by d and we have,
$d = 250\,Km$
and ram starts his journey from Delhi at $6a.m$ in the morning and reaches to his destination Chandigarh at $11a.m$ so, total time taken by ram to reach Chandigarh from Delhi can be calculated as the number of hours in between $6\,a.m$ and $11\,a.m$

Number of hours of the ram’s journey is $11 - 6$ or $5hours$. So, now we have total time taken by ram to cover a distance of $d = 250Km$ is $t = 5hr$
From the definition of average speed we have,
$Spee{d_{average}} = \dfrac{\text{Distance}}{\text{time}}$
$\Rightarrow Spee{d_{average}} = \dfrac{d}{t}$
On putting the values we get,
$Spee{d_{average}} = \dfrac{{250}}{5}$
$\therefore Spee{d_{average}} = 50\,Km\,h{r^{ - 1}}$

Hence, the average speed of ram is $Spee{d_{average}} = 50\,Km\,h{r^{ - 1}}$.

Note:It should be remembered that, while solving such questions, we always check whether we need to find average speed or average velocity because average speed is a scalar quantity whereas the average velocity is a vector quantity which needs specific direction to determine it. Also $Km$ is a big unit of meter which is related as $1\,Km = 1000\,m$ and similarly hour is a big unit of time and it’s related as $1\,Hour = 3600\sec $.