Question

question 23 of 25
a person launches two model rockets, which reach the same altitude. one rocket weighs 1.5 n, and the other weighs 3.2 n. how does the mass of the rockets relate to the force of gravity on them?

a. the mass of the 1.5 n rocket will be the same as the mass of the 3.2 n rocket when they reach the same altitude.
b. the mass of the 1.5 n rocket is less than the mass of the 3.2 n rocket.
c. the 1.5 n rocket and the 3.2 n rocket have the same mass before they are launched.
d. the 1.5 n rocket has more mass than the 3.2 n rocket.

Explanation:

Step1: Recall weight - mass relationship

Weight $W = mg$, where $W$ is weight, $m$ is mass and $g$ is acceleration due to gravity ($g\approx9.8\ m/s^{2}$ on Earth and is constant for both rockets).

Step2: Analyze mass for different weights

From $W = mg$, we can get $m=\frac{W}{g}$. Since $g$ is constant, the mass is directly proportional to the weight. The rocket with weight $W_1 = 1.5\ N$ and the rocket with weight $W_2=3.2\ N$. As $1.5<3.2$, the mass of the $1.5\ N$ rocket is less than the mass of the $3.2\ N$ rocket.

Answer:

B. The mass of the 1.5 N rocket is less than the mass of the 3.2 N rocket.