# A car starts from rest and moves along the x-axis with constant acceleration

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A car starts from rest and moves along the x-axis with constant acceleration 5m/ s2 for 8 sec. If it then continues with constant velocity, what distance will the car covers in 12 seconds start from the rest?

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We are given that

Case - I:

when t = 0, u = 0 when t = 8 sec, v = ?

Acceleration (a) = 5 m/s2

∴ v = u + at

= 0 + 5 x 8 = 40 m/s

s = ut + $\frac{1}{2}$ at2

s = 0 + $\frac{1}{2}$ x 5 x (8)2 = $\frac{1}{2}$ x 5 x 64 = 160m

Case-II: t = 8 sec to t = 12 sec.

Distance = speed x time

= 40 x 4 = 160 m.

So, the total distance travelled

= 160 + 160 = 320 m.