While we often think of weight and mass as being the same in everyday life, keep in mind that in physics, these terms have different meanings. Mass is an intrinsic property of an object. It depends on the material(s) the object is made of, and its size. So an object will have the same mass no matter where it is. Weight, however, depends on the gravitational force, which, as we will later see, depends on the mass of the planet or body exerting the force. On the Moon, for example, the acceleration due to gravity is about 1/6th of the value on Earth, or about 1.63 m/s. An object would weigh 1/6th as much on the Moon as it does on Earth, even though it has the same mass. Astronauts in orbit around the Earth, such as those on board the International Space Station, are often said to be "weightless", as they freely float around inside the station. But this is only because they are in a constant state of "free-fall" as they orbit, not because there is no weight force on them. There is still a gravitational force acting on them-if there weren't, they wouldn't stay in orbit around the Earth, but would drift off into outer space. A more accurate description of this state of constant free-fall would be "apparent weightlessness." The total mass of an astronaut wearing a space suit is 185 kg. What is the weight (in N) of the suited astronaut on Earth? * Check your arithmetic. Remember, the weight (on Earth) is found by multiplying the mass by 9.8 m/s (the value of g on Earth). N What is the weight (in N) of the astronaut on the Moon, where g = 1.63 m/s? Note the mass is still the same. Now, find the weight on the Moon by multiplying the given mass by the value of g on the Moon. N What is the weight (in N) of the astronaut on Mars, where g = 3.72 m/s? Enter a number. ss is still the same. Now, find the weight on Mars by multiplying the given mass by the value of g on Mars. N