An astronaut weighs 198 pounds in his spacesuit when weighed on Earth. What would this astronaut weigh on a planet whose mass is 3.8 Earth masses and whose radius is 1.3 Earth radii?

Question

Need to find the weight of this astronuat in pounds.

Answer 1

The formula for gravitational force is:

F=G*m₁*m₂/r²

From this we can see that the force of gravity is proportional to the planet's mass and inversely proportional to the square of the radius. If we start with the astronaut's 198 lbs, we can multiply by the mass ratio and divide by the square of the radius ratio.

198 lbs * 3.8 (mass ratio) * 1/1.3² (inverse square of radius ratio)