Question

A sports car accelerates in third gear from 48.3 km/h (about 30 mi/h) to 80.5 km/h (about 50 mi/h) in 3.70 s. a) What is the average acceleration of this car in mi/s? b) If the car maintained this acceleration, how fast would it be moving one second later?

Answer 1

a) Average acceleration

$A_{av}=\frac{dv}{dt}$

$=\frac{80.5-48.3}{3.6×3.7} =2.42m/s^2$

3.6 is change from km/h to m/s

b)

$V=Vi+a×t$

$=\frac{80.5}{3.6}+2.42×1.0=24.781m/s=89.211km/h$