Question

Car require a velocity of 72 km per hour in 10 seconds starting from rest find the average velocity

Answer 1

Answer:

10 m/s

Explanation:

As per the the provided information in the given question, we have :

• Initial velocity (u) = 0 m/s (As it starts from rest)
• Final velocity (v) = 72 km/h
• Time taken (t) = 10 seconds

We are asked to calculate the average velocity.

In order to calculate the average velocity, firstly we need to convert final velocity in m/s.

$\longmapsto\bf {v = 72 \; kmh^{-1} }$

• 1 km/h = 5/18 m/s

$\longmapsto\bf {v = \Bigg ( 72 \times \dfrac{5}{18} \Bigg ) \; ms^{-1} }$

$\longmapsto\bf {v = ( 4 \times 5 ) \; ms^{-1} }$

$\longmapsto\bf {v = 20 \; ms^{-1} }$

Now, as we know that,

$\longmapsto \boxed { \bf { \overline{\nu} = \dfrac{v + u}{2} }}$

• $\rm \overline{\nu}$ denotes average velocity.
• v denotes final velocity
• u denotes initial velocity

$\longmapsto { \bf { \overline{\nu} = \dfrac{20 +0 }{2} \; ms^{-1}}}$

$\longmapsto { \bf { \overline{\nu} = \cancel {\dfrac{20}{2}} \; ms^{-1} }}$

$\longmapsto { \bf { \overline{\nu} = 10 \; ms^{-1} }}$

Therefore, average velocity is 10 m/s.

More Information :

• Velocity is defined as the distance covered in the specific direction (displacement) divided by time taken.
• SI unit of velocity is m/s.
• It is a vector quantity.
• It is denoted by v.

Average velocity can also be found using the formula :

★ Distance = Average velocity × Time