Question

A train accelerates from 36 km/h to 54 km/h in 10 secs. Find 1 Acceleration 2 the distance by car

Answer 1

Answer

Initial velocity , u = 36 km/h = 10 m/s

Final velocity , v = 54 km/h = 15 m/s

∵ 1 km/h = ⁵/₁₈ m/s

Time , t = 10 s

1 .

Acceleration : It is defined as rate of change in velocity .

$:\to \bf a=\dfrac{v-u}{t} \\\\:\to \rm a=\dfrac{15-10}{10}\\\\:\to \rm a=\dfrac{5}{10}\\\\:\to \rm a=\dfrac{1}{2}\ m/s^2\ \; \pink{\bigstar}$

2 .

3 rd equation of motion :

• v² - u² = 2as

$:\to \rm (15)^2-(10)^2=2\left(\dfrac{1}{2}\right)s\\\\:\to \rm 225-100=s\\\\:\to \rm s=125\ m\ \; \blue{\bigstar}$