Always use significant figure rules. remember that these rules apply to all numbers that are measurements. an object on earth has a mass of 4 kg. calculate its weight on another planet that has an acceleration due to gravity one-half that of the earth. w2 = n

19.6 kg*m/s^2 = 19.6 N

Explanation:

Weight is mass times acceleration due to gravity.  And hopefully you know that acceleration due to gravity on earth is 9.8 m/s^2  So what is half of that?  4.9.  So now the calculation is super simple.

mass = 4 kg and acceleration = 4.9 m/s^2 so now we multiply these two numbers and get 19.6 kg*m/s^2.  kg*m/s^2 is also known as Newtons, abbreviated with an N so the final result is 19.6 N.