Answer:
Mass of the rock on Earth, m = 5 kg
Step-by-step explanation:
Given that,
Mass of the rock, m = 5 kg
We need to find its mass of the rock on earth. The relationship between the mass of an object and its weight is given by :
W = m × g
Where g is the acceleration due to gravity,

m is the mass which remains constant at every location.
So, the mass of the rock on earth is 5 kg. Hence, this is the required solution.