Examkin

Question

Difficulty: EasyMass versus Weight

A steel construction beam has a mass of 120 kg120 \text{ kg} on Earth, where the gravitational acceleration is approximately 10 m/s210 \text{ m/s}^2. The beam is subsequently transported to a lunar outpost, where the local gravitational acceleration is 1.6 m/s21.6 \text{ m/s}^2. What is the mass of the beam on the lunar outpost?

  1. A
    19.2 kg19.2 \text{ kg}
  2. B
    192 kg192 \text{ kg}
  3. 120 kg120 \text{ kg}Answer
  4. D
    192 N192 \text{ N}

Answer

120 kg120 \text{ kg}
The correct answer is 120 kg120 \text{ kg} because mass represents the physical amount of matter in the steel beam. This property is invariant and does not change when moved to a different gravitational environment, unlike weight.

Step-by-Step Solution

1
Identify the quantity requested in the problem.
The question specifically asks for the mass of the beam on the Moon.
Carefully distinguishing between requested mass and weight prevents calculation errors based on gravity.
2
Recall the definition and properties of mass.
Mass is the amount of matter in an object and is an invariant property, meaning it does not change based on location.
Unlike weight, which is a force dependent on the local gravitational acceleration (W=mgW = mg), mass remains constant universally.
3
Determine the mass on the Moon based on its initial mass.
Since the mass on Earth is 120 kg120 \text{ kg}, the mass on the Moon remains exactly 120 kg120 \text{ kg}.
The change in gravitational acceleration from 10 m/s210 \text{ m/s}^2 to 1.6 m/s21.6 \text{ m/s}^2 affects only the weight of the object, not its mass.

Key Concept

Mass is an intrinsic, invariant property of an object (measured in kilograms), whereas weight is the location-dependent gravitational force exerted on that mass (measured in Newtons).
Rate this question

Topics

Mass versus Weight

More questions from this topic