On a planet far, far away, an astronaut picks up a rock. the rock has a mass of 5.10 kg, and on this particular planet its weight is 40.0 n. if the astronaut exerts an upward force of 53.1 n on the rock, what is its acceleration?

Weight of an object is the gravitational pull exerted on the surface of a planet by the object. In this case the rock of mass 5.10 kg exerts a weight/force of 40.0 N, we can use this to calculate the gravitational acceleration (g) on the planet.
g = weight (N) ÷ mass (kg)
thus g = 40.0 N ÷ 5.10 kg = 7.84 N/kg
hence g  is 7.84 N/kg
Now if the astronaut exerts a difference force on the rock the acceleration changes but mass remains constant.
thus g = 53.1 N ÷ 5.10 kg = 10.41 N/kg
therefore the new g = 10.41 N/kg
Its important to note that unlike the weight of an object which varies depending on the gravitation acceleration , the mass of an object is always constant

Iwould sure like to answer your question but i honestly just don’t know