Question

An astronaut weighing 190 lbs on Earth is on a mission to the Moon and Mars.

Required:
a. What would he weigh in newtons when he is on the Moon?
b. How much would he weigh in newtons when he is on Mars, where the acceleration due to gravity is 0.38 times that on Earth?

Answer 1

The astronaut would weigh 31.7 lbs or 141 N on the Moon, and 72.2 lbs or 321 N on Mars.

Step-by-step explanation:

On the Moon, the acceleration due to gravity is about 1/6th of what it is on Earth. So the astronaut would weigh approximately 31.7 lbs or 141 N on the Moon.

On Mars, the acceleration due to gravity is about 0.38 times that on Earth. So the astronaut would weigh approximately 72.2 lbs or 321 N on Mars.

Answer 2

The weight is defined as:

W = m*g

where:

m = mass

g = gravitational acceleration.

We know that in Earth the astronaut weights 190 lb-f (this is force, not mass, the correct unit here is 190 lb*m/s^2)

then:

190 lb*m/s^2 = m*9.8m/s^2

(190 lb*m/s^2)/(9.8m/s^2) = 19.39 lb

Now we know the mass of the astronaut.

a) wieght on the moon in Newtons.

Newtons uses kilograms as the units of mass, then we need to rewrite the mass of the astronaut in kg.

we know that 1lb = 0.454 kg

Then 19.39 lb is equal to: 19.39*0.454 kg = 8.8 kg

We know that the acceleration due to gravity on the Moon is one-sixth that on Earth.

then: g = (9.8m/s^2)/6

And the weight of the astronaut in the moon will be:

W = 8.8 kg*(9.8m/s^2)/6 = 14.37 N

b) The weight on mars, where the acceleration due to gravity is 0.38 times that on Earth, we have:

g = (9.8m/s^2)*0.38

then the weight will be:

W = 8.8kg*(9.8m/s^2)*0.38 = 32.77 N