Question

If a train travelling at 72 km/hr is to be brought to rest in a distance of 200 metres, find the retarding force . If the mass of the train is 100 metric tons​

Answer 1

Answer:

Explanation:

speed of train= 72 km/hr

                      = 72×$\frac{5}{18} m/s$

                      =20m/s

∵ the train comes to rest , v=0

∴ $v^{2}$=$u^{2} -2aS; a_{2}$ retardation here

     => u^2=2aS

     => a=u^2/2S=$\frac{20*20}{2*200}$

     => 1m/s^2

∴ retardation = 1 m/s^2

the retardation should be 1m/s^2

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Answer 2

$\huge\underline\blue{\sf Answer:-}$

☑${\bold{\underline{\underline{Given:-}}}}$

➡Speed of train(u) = 72km/h =20m/s

➡V=0(Train comes to rest)

➡Distance=0

☑$\textbf{\underline{\underline{To find:-}}}$

➡Retardation =❓

☑$\textbf{\underline{\underline{Step-by-step-explanation:-}}}$

By using the relation:-

V^2-U^2=2as

❇[a= negative]❇

➡(0)^2=u^2=2as

➡u^2=2as

➡a=u^2/2a

➡a= 20x 20/2x200

➡a=400/400

➡a=1m/s^2

➡Retardation= 1m/s^2