A train is travelling with a velocity of 40 km h-1 What should be the acceleration on it so that it may reach a point 10 km ahead in 8 minutes? () What will be its velocity on reaching that point?
Answers
velocity= 110 km/h
hope it helps you
Answer:
a = 0.04 m/s² , v = 30.5 m/s
Explanation: Let the required acceleration be 'a'.
In the question, (unit chosen = km/hr)
Initial velocity(u) = 40 km/hr
Time taken(t) = 8min = (2/15) hr
Displacement(S) = 10 km
Using equations of motion:
⇒ S = ut + 1/2 at²
⇒ 10 = (40)(2/15) + 1/2 a (2/15)²
⇒ 10 = 80/15 + 2a/225
⇒ 10 = (1200 + 2a)/225
⇒ 2250 = 1200 + 2a
⇒ 1050 = 2a
⇒ 525 km/hr² = a
Converting this in m/s², we get
a = 525 (1000)/(3600)² m/s²
a ≈ 0.04 m/s²
(ii): Let the final velocity be 'v'.
⇒ v = u + at
⇒ v = 40 + (525)(2/15)
⇒ v = 110 km/hr
Converting this in m/s:
v = 110 (1000)/(3600) m/s
v ≈ 30.5 m/s
*question is solved with units km and hr and then converted to m and s.