Question

A car travelling at 20km/h speed up to 60km/h in 6 seconds. What is it's acceleration?

Answer 1

u = 20km/h => 20×5/18 => 10×5/9 => 50/9 m/s
v = 60 km/h => 60×5/18 => 10×5/3 => 50/3 m/s
t = 6sec


acceleration = ?


using first equation of motion ,

v = u+at
50/3 = 50/9 + a(6)
50/3 -50/9 = 6a
150/9-50/9 = 6a

100/9 = 6a

=> 100/9×6 = a
=> 100/54 = a
=> 50/27 m/s² = a
=> 1.85 m/s² = a



hope this helps

Answer 2

20 kmph = 20 × 5/18 m/s
60 kmph = 60 × 5/18 m/s

Acceleration = (v - u) / t
= [(60 - 20) × 5/18] / 6
= 1.85 m/s^2

Acceleration of car is 1.85 m/s^2