Gravity & Weight Flashcards

All 6 cards in this deck

What is the equation for weight?

$W = m \times g$

weight (N) = mass (kg) × gravitational field strength (N/kg)

What is the value of the gravitational field strength $g$ at the surface of the Earth?

About $10$ N/kg

Which two properties of a body in space determine the value of $g$ at its surface?

Its mass and its radius.

Greater mass gives larger $g$; larger radius gives smaller $g$.

What are the steps to calculate the weight of an object on another body in space?

e.g. a 60 kg astronaut on the Moon, where $g = 1.6$ N/kg

1. Use $W = m \times g$
2. Use the $g$ for that body: $W = 60 \times 1.6$
3. Weight $= 96$ N

True or false? An astronaut's mass is smaller on the Moon than on Earth.

False. Mass is the same everywhere; it is the weight that is smaller because $g$ is smaller on the Moon.

True or false? Two planets with the same mass have the same $g$ at their surfaces.

False. The planet with the larger radius has the smaller surface $g$.