Solve the problem.
-You are driving along a highway at a steady $86 \mathrm { ft } / \mathrm { sec }$ when you see a deer ahead and slam on the brakes. What constant deceleration is required to stop your car in $264 \mathrm { ft }$ ?
A) $14.01 \mathrm { ft } / \mathrm { sec } ^ { 2 }$
B) $28.02 \mathrm { ft } / \mathrm { sec } ^ { 2 }$
C) $7.00 \mathrm { ft } / \mathrm { sec } ^ { 2 }$
D) $0.07 \mathrm { ft } / \mathrm { sec } ^ { 2 }$

Question

Quizplus · Accepted Answer

To solve this problem, we can use the kinematic equation $v^2 = u^2 + 2as$, where $v$ is the final velocity, $u$ is the initial velocity, $a$ is the acceleration (deceleration in this case), and $s$ is the distance. Since the car comes to a stop, $v = 0$, $u = 86 \mathrm { ft } / \mathrm { sec }$, and $s = 264 \mathrm { ft }$. Rearranging the equation for $a$ gives $a = \frac{-u^2}{2s}$. Plugging in the values gives $a = \frac{-(86)^2}{2(264)} = -14.01 \mathrm { ft } / \mathrm { sec } ^ { 2 }$. The negative sign indicates deceleration.

Solve the Problem 86ft/sec86 \mathrm { ft } / \mathrm { sec }86ft/sec

Solve the Problem $86 \mathrm { ft } / \mathrm { sec }$