Everything Science Grade 10

21.7 CHAPTER 21. MOTION IN ONE DIMENSION

Displacement = Area+Area△

∆~x = vit+^12 vft−^12 vit

∆~x = (vi+ 2 vf)t

Derivation of 21.3

This equation is simply derived by eliminating the final velocityvfin 21.2. Remembering
from 21.1 that

~vf=~vi+~at

then 21.2 becomes

∆~x = ~vi+~v 2 i+~att

=^2 ~vit 2 +~at^2

∆~x = ~vit+^12 ~at^2

Derivation of 21.4

This equation is just derived by eliminating the time variable in the above equation. From
21.1 we know

t=~vf−a~vi

Substituting this into 21.3 gives

432 Physics: Mechanics