Question

A car speed reduces its speed from 40km/hr to 10km/hr in 5seconds then its accelaration is

Answer 1

acc is rate of change of velocity

initial speed,u=40km/hr=11.11m/s

final speed,v=10km/hr=2.77m/s

time ,t=5sec

acceleration,a=?

$a = \frac{v - u}{t}$

$a = \frac{2.77 - 11.11}{5} m {s}^{ - 2}$

$a = \frac{ - 8.34}{5} m {s}^{ - 2}$

$a = - 1.668m {s}^{ - 2}$

where -ve sign indicates retardation