Question

1. an athlete running at 7 m/s accelerates at 2.5 m/s² for 6 seconds. what is the athletes final velocity after the acceleration? 12. an airplane decelerates on the runway at a rate of -4 m/s². with a velocity of 60 m/s and slows down, what is its final velocity after 15 seconds?

Explanation:

Step1: Identify the kinematic - equation

The kinematic equation $v = v_0+at$ is used, where $v$ is the final velocity, $v_0$ is the initial velocity, $a$ is the acceleration and $t$ is the time.

Step2: Solve for the first - problem

Given $v_0 = 7\ m/s$, $a = 2.5\ m/s^2$ and $t = 6\ s$. Substitute into the equation $v = v_0+at$.
$v=7 + 2.5\times6$
$v=7 + 15$
$v = 22\ m/s$

Step3: Solve for the second - problem

Given $v_0 = 60\ m/s$, $a=-4\ m/s^2$ and $t = 15\ s$. Substitute into the equation $v = v_0+at$.
$v=60+( - 4)\times15$
$v=60 - 60$
$v = 0\ m/s$

Answer:

1. The final velocity of the athlete is $22\ m/s$.
2. The final velocity of the airplane is $0\ m/s$.