Question

kenna takes her dog for a run. they start walking at a speed of 3.5 mph and accelerate to a speed of 6.0 mph over 30 seconds. what is kennas acceleration? -0.083 mi./hr./sec. 0.10 mi./hr./sec. 0.083 mi./hr./sec. 0.83 mi./hr./sec.

Explanation:

Step1: Recall acceleration formula

Acceleration $a=\frac{\Delta v}{\Delta t}$, where $\Delta v$ is change in velocity and $\Delta t$ is change in time.

Step2: Calculate change in velocity

Initial velocity $v_1 = 3.5$ mph, final velocity $v_2=6.0$ mph. So $\Delta v=v_2 - v_1=6.0 - 3.5 = 2.5$ mph.

Step3: Calculate acceleration

$\Delta t = 30$ s. $a=\frac{\Delta v}{\Delta t}=\frac{2.5\text{ mi/hr}}{30\text{ s}}\approx0.083$ mi/hr/sec.

Answer:

0.083 mi/hr/sec