Question

A car starts from rest amd attains a speed of 40km/h after 10 seconds. Calculate the acceleration of the car in km/h²

Answer 1

Hope this helps you!!!

Answer 2

answer

Bus starts from rest , it means initial velocity of bus , u = 0

Bus attains 40 km/h velocity after 10sec

final velocity of bus , v = 40 km/h = 40 × 5/18 m/s [ we know, 1 km/h = 5/18 m/s ]

v = 100/9 m/s

Time taken by bus , t = 10sec

we should use formula,

v = u + at

from above , v = 100/9 m/s , u = 0 and t = 10sec

Now, 100/9 = 0 + a × 10

⇒ 100/9 = 10a

⇒ a = 10/9 m/s²

Hence, acceleration of bus in m/s² = 10/9 m/s²

Now, acceleration of bus in Km/h²

v = 40 km/h , u = 0 and t = 10sec = 10/3600 hr = 1/360 hr

Now, from formula ,

V = u + at

40 = 0 + a × 1/360

40 = a/360

a = 40 × 360 = 14400 km/h²

Hence, (a) 14400 km/h²

(b) 10/9 m/s²