Question

An Apple sits on a table which is 3 m above the floor. The acceleration due to gravity could be our earths value of g equals 10 m/s^2 or something larger or smaller. In this case the acceleration due to gravity is 3*g. What is the speed acquired by the Apple just before it hits the floor? How long does the Apple take to fall through the h meters? What is the initial potential energy in Joules possessed by the Apple if it’s mass is 0.1 kg? What is the kinetic energy that the Apple acquired after it falls through the entire 3 meters?

Answer 1

$\begin{gathered} h=3m \\ g=10m/s^2 \\ m=0.1\operatorname{kg} \\ \text{Question 1} \\ v^2_f=2gh \\ v_f=\sqrt{2gh} \\ v_f=\sqrt[]{2(10m/s^2)(3m)} \\ v_f=\sqrt[]{60m^2/s^2} \\ v_f=7.75\text{ m/s} \\ \text{The velocity just before reach the ground is 7.75m/s} \\ \\ \text{Question 2} \\ v_f=gt \\ \text{Solving t} \\ t=\frac{v_f}{g} \\ t=\frac{7.75\text{ m/s}}{10m/s^2} \\ t=0.775\text{ s} \\ \text{The time in air is 0.775s} \\ \\ \text{Question 3} \\ P=mgh \\ P=(0.1kg)(10m/s^2)(3m) \\ P=3J \\ \text{The potential energy is 3 joules} \end{gathered}$