A car accelerates uniformly from rest to a speed of 21.0 km/h in 5.6 s. Find the distance the car travels during this time. Answer in units of m.

Expert Answers

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The motion of the car has a constant acceleration. In this case we will use the expression of the acceleration and the expression of distance for the uniformly varied movement.

The acceleration is defined as:

a = (v – v0)/t


 v – v0  →  Variation of speed, at time t

The speed variation, is from zero to 21 km/h in a time of 5.6 seconds.

21 km/h = (21)(1000/3600) = 5.83 m/s

Then the acceleration is:

a = (5.83 – 0)/5.6 = 1.04 m/s^2

Now, we apply the expression of distance:

d = v0t + at^2/2

d = 0 + (1.04)(5.6)^2/2

d = 16.3 m

Then, this car travels 16.3 m in a time of 5.6 s

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