An astronaut on another planet drops a 1-kg rock from rest and finds that it falls a vertical distance of 2.5 meters in one second. On this planet, the rock has a weight of
A)1 N.
B)2 N.
C)3 N.
D)4 N.
E)5 N.

Question

Quizplus · Accepted Answer

The weight of an object is calculated by the formula $W = mg$, where $m$ is the mass of the object and $g$ is the acceleration due to gravity. To find $g$, we use the formula for distance covered under uniform acceleration, $d = \frac{1}{2}gt^2$, where $d$ is the distance, $g$ is the acceleration due to gravity, and $t$ is the time. Substituting $d = 2.5$ meters and $t = 1$ second, we get $2.5 = \frac{1}{2}g(1)^2$, which simplifies to $g = 5$ m/s$^2$. Therefore, the weight of the rock is $W = 1 \text{ kg} \times 5 \text{ m/s}^2 = 5 \text{ N}$.

An Astronaut on Another Planet Drops a 1-Kg Rock from Rest