Friday, February 26, 2016

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.

The required equation of motion


v^2-u^2=2as                      (1), where v= final velocity and u is initial vlocity , a is the uniform acceleration and s is the displacement.


v= 21kms/hr = 21000/3600=5.833333m/s


But a =(v-u)/5.6 =(5.83333-0)/5.6 = 1.0416666m/s^2


v=5.833333m/s, u=0m/s, a=0.041666m/s^2 and s is to be found out.


By sustitutin in (1), we get:


5.83333^2-0^2 = 2*1.0416666*s


5.83333^2/(2*1.1416666) =s


s= 16.3333 m is the distance travelled by the car.

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