A car is accelerating uniformly as it passes two check points that are 30 m apart. The time taken between check points is 4.0 s ….

Q: A car is accelerating uniformly as it passes two check points that are 30 m apart. The time taken between check points is 4.0 s and the car’s speed at the first check point is 5.0 ms-1. Then,

(a) the velocity of car at second check point is 10 ms-1

(b) the velocity of car at second check point is 20 ms-1

(c) the acceleration of car is 2.5 ms-2

(d) the acceleration of car is 1.25 ms-2

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Ans: (a) , (d)
Sol: $\displaystyle S = u t + \frac{1}{2} a t^2 $

$\displaystyle 30 = 5 \times 4 + \frac{1}{2} a (4)^2 $

$\displaystyle 30 = 20 + 8 a $

8 a = 10

a = 1.25 m/s2

v = u + a t

v = 5 + 1.25 × 4

v = 10 m/s