Final answer:
Assuming the rock has a mass of 1 kg, the potential energy of the rock 100 meters above planet X, with a gravitational acceleration of 8.0 m/s², can be calculated using the formula PE = mgh, resulting in 800 Joules.
Explanation:
To calculate the potential energy of the rock on planet X, you can use the formula for gravitational potential energy, which is PE = mgh, where PE stands for potential energy, m is the mass of the object in kilograms, g is the gravitational acceleration, and h is the height above the reference point. In this case, since the mass of the rock is not given, we shall assume it to be the standard value used in such calculations, which is 1 kg (This is a typical assumption used in physics problems when the mass is not specified). The gravitational acceleration (g) on planet X is given as 8.0 m/s², and the height (h) is 100 meters. Therefore, the potential energy (PE) of the rock 100 meters above the surface of planet X would be calculated as follows:
PE = mgh
PE = (1 kg)(8.0 m/s²)(100 m)
PE = 800 J
Thus, the potential energy of the rock is 800 Joules. Hence, the correct answer is (a) 800 J.