#"As the train moves on curvilinear path,a centrifugal force"#
#"occurs on the pendulum bob."#
#tan theta=(m*v^2/r)/(mg)#
#tan theta=cancel(m)*v^2/r*1/(cancel(m)g)#
#tan theta=v^2/(r g)#
#v^2=r g tan theta#
#v:"speed of train"#
#r:400 m#
#theta:5^o#
#g:9.81" "N/(kg)#
#v^2=400*9.81*tan 5^o#
#v^2=343.31#
#v=sqrt(343.31)#
#v=18.53" "m/s#