physics question

Question

The acceleration due to gravity on the surface of a planet is 6.5 m/s2. An astronaut’s life support backpack weighs240 N on Earth. What does it weigh on Mars?

Answer 1

Using Newton's 2nd Law.

F_g = ma (F_g is the Force of Gravity -- in other words, the "weight" of an object. And the "a" here is the acceleration, due to gravity.)

FIrst find the mass of the backpack.

m = F_g/g

where g = the acceleration due to gravity, 9.8 m/s² on Earth (we usually use 10 m/s² as it is easier to work with)

m = (240 N) / (10 m/s²)

m = 24 kg

Now for new planet.

F_g = mg

= (24 kg)•(6.5 m/s²)

= 156 N

Remember - weight is a FORCE (the Force of gravity) and we measure ALL forces in terms of Newtons. Also remember that 1 Newton = 1 kg•m/s² , that is a bit klunky so we named it a Newton (after Sir Issac, of course.)

Answer 2

m = W/g = (240 N)/(9.8 m/s²) = ? kg

On Mars,

W₁ = mg₁

Use the mass m found above, and use g₁ = 6.5 m/s².