Chapter 16, Problem 30A

An astronaut awakes in her closed capsule, which actually sits on the moon. Can she tell whether her weight is the result of gravitation or of accelerated motion? Explain.

To determine

Whether the astronaut can tell that her weight is due to the result of gravitation or accelerated motion.

Answer to Problem 30A

No

Explanation of Solution

Introduction: The weight of an object is measured as the product of mass (amount of matter it contains) and the force exerted on it either by gravity or by acceleration generated by the force applied on it.

On Earth and Moon, the gravitational force is applied which is used to measure the weight of any living or non-living entity. If the capsule in which the astronaut is in, rests on the surface of the Moon then the gravitational force is applied to it and weight is calculated as However, if the capsule is not resting on the surface then either it is accelerating or decelerating. Thus, force applied to the mass can be calculated as Here, and are the same i.e. acceleration applied on the mass but is different in terms of cause.

In the problem, it cannot be determined whether the weight can be measured based on the gravitational effect or the basis of the accelerating force of the capsule. Thus, she is unsure that her weight is due to acceleration or deceleration due to the motion of the capsule or due to the gravitational potential energy applied to the pod by Moon.

Conclusion: Thus, the astronaut cannot tell if her weight is due to the gravitational effect of the Moon or due to the acceleration of the capsule because it is not sure if the capsule is at rest or in motion.