Physics
posted by Seth on .
A train has a mass of 5.22 multiplied by 106 kg and is moving at 70.0 km/h. The engineer applies the brakes, which results in a net backward force of 1.87 multiplied by 106 N on the train. The brakes are held on for 37.0 s.
(a) What is the new speed of the train?
(b) How far does it travel during this period?

A train has a mass of 5.22*106kg? That is a really lightweight train. Think about that. My pickup truck weighs much more than that.
Vf=vi+a t
change vi 70km/h to m/s
a= force/mass= 1.87*106N/(5.22*106)
solve for vf
distance: avg velocity*time= (vi+Vf)*t/2