Question

A car traveling in a straight line has a velocity of +4.5 m/s. After 5.0 s, its velocity is +7.0 m/s. What is the car's average acceleration in this time interval?

Answer 1

Question 34498

An average acceleration in time interval between $t_1$ and $t_2$ is by definition $a = \frac{\Delta v}{\Delta t}$ , where $\Delta v = v_2 - v_1$ and $\Delta t = t_2 - t_1$ . So to say, this is the "speed of change in speed".

Given $v_{1} = 4.5\frac{m}{s}$ , $v_{2} = 7\frac{m}{s}$ and $\Delta t = 5s$ , obtain $a = \frac{v_{1} - v_{2}}{\Delta t} = \frac{7\frac{m}{s} - 4.5\frac{m}{s}}{5s} = 0.5\frac{m}{s^{2}}$ - this is the car's average acceleration.