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10. If a sports car at rest accelerates unifomly to a speed of 144km/h in 5s, it covers a distance of100m 2). 140m 3) 60m 4) 80m​

Answer»

Option 1 : 100 mExplanation:Given:Initial velocity = 0 m/sFinal velocity = 144 km/hr = 40 m/sTime taken = 5sTo Find:Distance coveredConcept:First we have to find the acceleration of the car. Substituting the data in the second or THIRD equation of motion we get the distance covered by the car.Solution:Initially we have to find the acceleration of the carBy the first equation of motion,v = u + atwhere v = FINAL velocity            u = initial velocity            a = acceleration            t = time takenSubstitute the data 40 = 0 + a × 55A = 40  a = 40/5  a = 8 m/s²Hence acceleration of the car is 8 m/s²Now we have to find the distance covered by the carBy the third equation of motion,v² - u² = 2aswhere v = final velocity            u = initial velocity            a = acceleration            s = distance coveredSubstituting the data,40² - 0² =  2 × 8 × s16s = 1600    s = 1600/16    s = 100 mHence the distance covered by the car is 100 mTherefore option 1 is correct.



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