Question

a train stating from rest attains a maximum speed of 54km/h in 30 sec with uniform acceleration ,it then travels with the speed for 40sec and is then brought to rest in further 30sec with uniform retardation, calculate the total distance travelled

Answer 1

First case take u=0 m/s and v= 15m/s then find acceleration using v=u +at after that find distance using
$s = ut + \frac{1}{2} a {t}^{2}$
Next case take u=15 m/s and v=0 m/s and then continue with the same. Formulas
At the end add the distances