Question

A car acquires a velocity of 72 km/h in 10 seconds starting from rest find acceleration

Answer 1

Data:
Vi= 72 km/h             Vi= 72ooo/ 3600    =   20 m/s
we have to convert km into m and h into sec
   as 1km= 1000m and 1 hour = 3600 sec 
Vf= 0 
t = 10 sec

Required:
a= ?

Solution
According to 1st equation of motion
Vf= Vi + at
0 = 20 + a ( 10 )
- 20 = a (10)
-20 / 10=  a
a = -2 m/sec^2