Question

1. habib is driving down a mountain road and decelerates from 55 mph to 40 mph in 5 seconds. what is habibs acceleration? o 3 mi./hr./sec o -3 mi./hr./sec o 5 mi./hr./sec o -5 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 $v_1 = 55$ mph, final velocity $v_2=40$ mph. So $\Delta v=v_2 - v_1=40 - 55=- 15$ mph.

Step3: Convert time to appropriate units

Time $\Delta t = 5$ seconds. Since we want the acceleration in mi/hr/sec, we don't need to convert the time further for this problem.

Step4: Calculate acceleration

$a=\frac{\Delta v}{\Delta t}=\frac{-15\text{ mi/hr}}{5\text{ sec}}=- 3$ mi/hr/sec

Answer:

• 3 mi/hr/sec