a = (70-15)/15 = 11/3 km/hr/s
Convert that to m/s^2, and then use
s(t) = 15km/hr * 15s + 11/6 km/hr/s * 15s^2
= 15km/hr * 15/3600 hr + 11/6 km/hr/s * 15s * 15/3600 hr
= 225/3600 + 11/6 * 225/3600 km
= 17/96 km
or 177 m
Don't like mixing up all those units?
15km/hr = 4.167 m/s
70km/hr = 19.444 m/s
So, a = (19.444-4.167)/15 = 1.018 m/s^2
s(t) = 4.167t + 0.509t^2
= 4.167*15 + 0.509*225
= 177m
The maker of an automobile advertises that it takes 15 seconds to accelerate from 15 kilometers per hour to 70 kilometers per hour. Assuming constant acceleration,
(a) The distance the car travels during the 15 seconds (Round your answer to two decimal places.)
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2 answers