Question

1. a penny is thrown down a wishing well at a speed of 16 m/s. what will be the speed of the penny after 2.5 seconds?

$v_i = 16\\ m/s$
$v_f=?$
$a = 10\\ m/s^2$
$t = 2.5\\ seconds$
$v_f=v_i + at$
$v_f=16 + 10$

1. a stone is dropped from a cliff and hits the ground 4.5 seconds later. how high is the cliff?

Explanation:

Step1: Identify the kinematic - equation

The kinematic equation for final velocity is $v_f=v_i + at$, where $v_f$ is the final velocity, $v_i$ is the initial velocity, $a$ is the acceleration, and $t$ is the time.

Step2: Substitute the given values

Given $v_i = 16\ m/s$, $a= 10\ m/s^2$, and $t = 2.5\ s$.
Substitute into the equation: $v_f=16+10\times2.5$.

Step3: Calculate the final velocity

$v_f=16 + 25=41\ m/s$.

Answer:

$41\ m/s$