Example 8.6 - Chapter 8 Class 9 - Motion
Last updated at April 16, 2024 by Teachoo
Examples from NCERT Book
Last updated at April 16, 2024 by Teachoo
Example 8.6 A car accelerates uniformly from 18 km hβ1 to 36 km hβ1 in 5 s. Calculate (i) the acceleration and (ii) the distance covered by the car in that time. Initial velocity = u = 18 km /h Final velocity = v = 36 km /h Time taken = 5 second Converting initial and final velocity in m/s Conversion from km/h to m/s 1 km = 1000 m 1 hour = 60 minutes = 3600 s β΄ (1 ππ)/β = (1000 π)/(3600 π ) β΄ 1 km/h = 5/18 m/s Initial velocity = u = 18 km/h = 18 Γ 5/18 m/s = 5 m/s Final velocity = v = 36 km/h = 36 Γ 5/18 m/s = 10 m/s (i) Finding Acceleration Acceleration = (πΉππππ π£ππππππ‘π¦ β πΌπππ‘πππ π£ππππππ‘π¦)/(ππππ π‘ππππ) = (π£ β π’)/π‘ = (10 β 5)/5 = 5/5 = 1 m/s2 (ii) Finding Distance Travelled We know u, v, a and t Finding distance (s) by using 3rd equation of motion v2 β u2 = 2as (10)2 β (5)2 = 2 Γ 1 Γ s 100 β 25 = 2s 75 = 2s 75/2 = s s = 75/2 s = 37.5 m