A and B start from the same ground and direction at the same time. A moves in a straight line at a uniform speed of 6m / s. B starts from a standstill and moves in a straight line at a uniform acceleration of 3m / S2 How long does it take before B overtakes a? What is the distance between the two cars? (2) When does car B catch up with car a? What's the speed of car B at this time?

A and B start from the same ground and direction at the same time. A moves in a straight line at a uniform speed of 6m / s. B starts from a standstill and moves in a straight line at a uniform acceleration of 3m / S2 How long does it take before B overtakes a? What is the distance between the two cars? (2) When does car B catch up with car a? What's the speed of car B at this time?

1. At the same speed, the distance is the farthest
Let B move for t
t=V/a=(6m/s)/(3m/s²)=2s
The distance between them is: Δ x = x A-X B = (VT) - [(1 / 2) at & sup2;] = 12-6 = 6m
2. When catching up, the displacements are equal
X a = x B
(Vt')=[(1/2)at'²]
It is found that t '= 2V / a = (2 × 6m / s) / (3m / S & sup2;) = 4S
At this time, the speed of vehicle B: V '= at' = (3m / S & sup2;) × (4S) = 12m / s