question_answer

A train starting from rest, attains a velocity of 72 km/ h in 5minutes. Assuming that the acceleration is uniform, find (i) the acceleration and (ii) the distance travelled by the train while it attained the velocity.

Answer:

Here, Initial velocity, u = 0 Final velocity, \[v=72km/h=20m/s\] Time taken, t = 5 min = 300 s (i) Acceleration a = ? (to be calculate(d) (ii) Distance travelled S = ? (to be calculate(d) (i) From formula, v = u + at We have, \[a=\frac{v-u}{t}\] Putting values, we get, \[a=\frac{20-a}{300}=\frac{1}{15}m/{{s}^{2}}\] (ii) From formula\[S=\frac{u+v}{2}\times t\] Putting values, we get \[s=\frac{0+20}{2}\times 300=3000m\] or 3 km.