Question

a paper airplane with mass 0.1 kg is flying 1.5 m above the ground with a speed of 2 m/s. what is the total mechanical energy of the paper airplane?
a. 1.67 j
b. 0.2 j
c. 1.47 j
d. 2.22 j

Explanation:

Step1: Calculate kinetic energy

Kinetic energy formula: $K = \frac{1}{2}mv^{2}$. Given $m = 0.1\ \text{kg}$ and $v = 2\ \text{m/s}$, then $K=\frac{1}{2}\times0.1\times2^{2}= 0.2\ \text{J}$.

Step2: Calculate potential energy

Potential energy formula: $U = mgh$. Take $g = 9.8\ \text{m/s}^{2}$, $m = 0.1\ \text{kg}$, $h = 1.5\ \text{m}$, then $U=0.1\times9.8\times1.5 = 1.47\ \text{J}$.

Step3: Calculate total mechanical energy

Total mechanical energy $E=K + U$. Substitute $K = 0.2\ \text{J}$ and $U = 1.47\ \text{J}$, so $E=0.2+1.47=1.67\ \text{J}$.

Answer:

A. 1.67 J