Question

A car is moving from rest, after two hours velocityof car become 54km /hr , calculate acceleration in SI unit​

Answer 1

Explanation:

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

• Initial velocity (u) = 0 m/s
• Final velocity (v) = 54 km/h
• Time taken (t) = 2 hours

We are asked to calculate the acceleration in m/s² (SI unit).

Firstly, we need to convert final velocity in m/s and we have to convert time into seconds.

$\longmapsto \rm { v = 54 \; km \; h^{-1} } \\ \\ \longmapsto \rm { v = \Bigg ( 54 \times \dfrac{5}{18} \Bigg )\; m \; s^{-1} } \\ \\ \longmapsto \rm { v = \Bigg ( 3 \times 5 \Bigg )\; m \; s^{-1} } \\ \\ \longmapsto \underline{\bf { v = 15 \; m \; s^{-1} }}$

Now,

$\longmapsto \rm { t = 2 \; hours } \\ \\\longmapsto \rm { t = (2 \times 60) \; minutes } \\ \\ \longmapsto \rm { t = 120 \; minutes } \\ \\ \longmapsto \rm { t = (120 \times 60 )\; seconds } \\ \\ \longmapsto \underline{ \bf { t = 7200 \; seconds }}$

As we know that, acceleration is the rate of change in velocity. Its SI unit is m/s².

$\longmapsto \bf { a = \dfrac{v - u}{t} } \\ \\ \longmapsto \bf { a = \dfrac{(15-0)}{7200} \; m \; s^{-2} } \\ \\ \longmapsto \bf { a = \dfrac{15}{7200} \; m \; s^{-2} } \\ \\ \longmapsto \underline{\boxed{ \bf { a = 0.002083 \; m \; s^{-2} }}}$

∴ The acceleration is 0.002083 m/s².