Atrain moving west with an initial velocity of 20 m/s accelerates at 4 m/s2 for 10 seconds. during this time, the train moves a distance of meters.

So lets fill out what we have first:

Vi or initial velocity = 20 m/s

Acceleration or a = 4 m/s^2

Time for the motion = 10s

Now, using the four main kinematic equations we can deduce that the best kinematic equation to use in these terms is:

Δx = Vi(t) + 0.5at²

Plug all of our information in:

Δx = (20)(10) + (0.5)(4)(100)

Δx = 400 m

ice to water 1 water to vapour 2 latent heat

no. dot product   =0 when vecs at right angles