Answer:2155 J
Explanation:
Given
Change in Internal energy
i.e. decrease in Internal Energy
Heat added to system 
According First law for a system



Thus 2155 J of work is done by system
First we have to find out the gravity on that planet. We use Newton second equation of motion. It is given as,
s = ut +(gt^2)/2
Distance s = 25m
Time t = 5 s
Velocity u = 0
By putting these values,
25 = 1/2.g.(5)²
g = 2
So the gravity on that planet is 2. Lets find out the weight of the astronaut.
Mass of the astronaut on earth m = 80 kg
Weight of astronaut on earth W = mg = (80)(9.8) = 784 N
Weight of astronaut on earth like planet = (80)(2) = 160 N
x = 160N