Question

A particle starting from rest moves with constant acceleration. If it takes 5.0 s to reach the speed 18.0 km/h find the average velocity during this period .

Answer 1

Initial velocity of the particle, u = 0
Final velocity of the particle, v = 18 km/h = 5 m/s
Time, t = 5 s
Acceleration, a = (v − u)/t
⇒ a = (5 − 0)/5 = 1 m/s²
Distance,

\[s = \text{ut } + \frac{1}{2}\text{ at}^2\]

\[\Rightarrow s = \frac{1}{2} \times 1 \times \left( 5 \times 5 \right) = 12 . 5 \text{ m } \]

Average velocity,

\[v_{avg} = \frac{\text{ Total displacement } }{\text{ Total time taken } }\]

\[\Rightarrow s = \frac{1}{2} \times 1 \times \left( 5 \times 5 \right) = 12 . 5 \text{ m }\]