Question

A car traveling in a straight line has a velocity of 5.0 m/s. After an acceleration of 0.75 m/s/s, the cars velocity is 8.0. In what time interval did the acceleration occur?

Answer 1

4 seconds

Step-by-step explanation:

did it in class

Answer 2

vs - velocity on beginning
ve - velocity on ending. You've got:

`v_s = 5 (m)/(s) \\ v_e=8 (m)/(s) \\ \hbox{Then:} \\ \Delta v=v_e - v_s = 8 (m)/(s) - 5(m)/(s)=3 (m)/(s) \\ a=0,75 (m)/(s^2) \\ \hbox{And from formula:} \\ a=(\Delta v)/(\Delta t) \qquad \Rightarrow \qquad \Delta t= (\Delta v)/(a) \\ \hbox{Substitute:} \\ \Delta t=(3(m)/(s))/(0,75 (m)/(s^2))= (3)/((3)/(4)) s= 3 \cdot (4)/(3) s= 4 s`
So he needed 4 second.