Question

which describes what happens when you fly 10 km above the earth’s surface?
a) mass decreases, weight decreases
b) mass decreases, weight increases
c) mass remains constant, weight decreases
d) mass decreases, weight remains constant

Explanation:

1. Understand Mass and Weight Definitions:

• Mass is the amount of matter in an object. It is an intrinsic property and does not change with location (like moving to 10 km above Earth’s surface).
• Weight is the force of gravity on an object, calculated as \( W = mg \) (where \( m \) is mass and \( g \) is acceleration due to gravity).

1. Analyze Change in Gravity at 10 km Altitude:

• As altitude increases, the distance from Earth’s center increases. By the inverse - square law of gravity (\( F = G\frac{Mm}{r^{2}} \), where \( G \) is gravitational constant, \( M \) is Earth’s mass, \( m \) is object’s mass, and \( r \) is distance from Earth’s center), the gravitational force (and thus \( g \), since \( W = mg \)) decreases at 10 km above the surface.

1. Evaluate Each Option:

• Option A: Mass does not decrease (mass is constant), so A is wrong.
• Option B: Mass does not decrease and weight does not increase (weight decreases due to lower \( g \)), so B is wrong.
• Option C: Mass is constant (intrinsic property) and weight decreases (because \( g \) decreases with increased altitude), so C is correct.
• Option D: Mass does not decrease and weight does not remain constant (weight decreases), so D is wrong.

Answer:

C) mass remains constant, weight decreases