Need with all four and you < 3

According to newton's second law of motion;

Force (weight of an object) = Mass × Acceleration

Weight of a 31kg object = 31kg × 10m/s² = 310N

Acceleration due to gravity on moon is less than that on earth so objects have little weight on moon than on earth.

The weight of a 31kg onject on moon is therefore × 310N ≈ 51.7N

The mass of the object on earth is 31Kg.

In the formula; Force = Mass × Acceleration

Mass here is a constant on the acceleration changes so:

The mass of the object on moon is also 31Kg.

i think it'll be 7,000

diagram is missing, but i will try to explain your doubt.

answer:

amplitude is the maximum displacement or distance moved on a point of a vibrating body or wave measured from its equilibrium position.it is equal to half the length of vibration path.