Question

a toy plane has a mass of 2.5 kg and is 18 m above the ground. it is moving at 4.5 m/s. how much mechanical energy does the toy plane have? 416 j 441 j 466 j 491 j

Explanation:

Step1: Calculate kinetic energy

$K = \frac{1}{2}mv^{2}$, where $m = 2.5\ kg$ and $v = 4.5\ m/s$. So $K=\frac{1}{2}\times2.5\times(4.5)^{2}=\frac{1}{2}\times2.5\times20.25 = 25.3125\ J$

Step2: Calculate potential energy

$U = mgh$, where $m = 2.5\ kg$, $g = 9.8\ m/s^{2}$, $h = 18\ m$. So $U=2.5\times9.8\times18=441\ J$

Step3: Calculate mechanical energy

$E = K + U$. So $E=25.3125 + 441=466.3125\ J\approx466\ J$

Answer:

466 J