Question

A train slows from 25m/s to 14m/s in 5.0s. Calculate the work done on the train....so I calculted the displacement and the force and put them together to get an answer of 5.0 x 10^7J, but my textbook says it should be 1.1 x 10^7J? Am I right, or is the textbook?

Merci beaucoup!

Answer 1

I don't know how you can do this without the mass of the train.

work done= change in KE
= 1/2 mass (25^2 -14^2)

Answer 2

i have the textbook, mass is 52 000kg
d = (v1 + v2)1/2 x t
a = change in velo/time
f = m x a
plug in numbers to w = fd