Solution!
A train is travelling at a speed of 40 km/ h.
Initial velocity [u] is 40 km/hr
Converting into m/s:
- 1 km = 1000 m
- 1 hr = 3600 secs
- u = 40 × 1000m/3600s
- u = 40 × 5/18
- u = 200/18
- u = 11.11 m/s
Acceleration [a] is - 0.5 m/s²
Since brakes are applied so final velocity [v] will be 0.
According to the third equation of motion,
- v² - u² = 2as
- 0² - 11.11² = 2 × 0.5 × s
- 123.43 = 1 × s
- s = 123.4 m
Hence The train will go 123.4 meters before it is brought to rest