A train having 60 compartments is pulled by engine with a force `6xx10^(4)` N. If mass of each compartment is 4000 kg the tension in the coupling between 40 th and 41st compartment is:

Options

A. `4xx10^(4)N`
B. `3xx10^(4)N`
C. `2.5xx10^(4)N`
D. `2xx10^(4)N`

Answer

D

Explanation

Let mass of each compartment be m.
`a=F/(60m)=(6xx10^(4))/(60m)=10^(3)/m`
Let tension in the coupling between 40 th and 41st compartment be T.
Then `T=(20m)a=(20m)xx10^(3)/m=2xx10^(4)N`