7a. [4 marks] Cars I and B are on a straight race track. I is moving at a constant speed of and B is
initially at rest. As I passes B, B starts to move with an acceleration of.
I passes B
B passes !
1
> 45ms-
> 45ms-1
B
at rest, begins to move
B
At a later time B passes I. You may assume that both cars are point particles.
Show that the time taken for B to pass I is approximately 28 s.