Energy stored or conserved in an object is known as potential energy. The position, arrangement, or state of the object or substance determines how much energy is stored.

Potential energy PE = mgh

Where, the mass in kilograms is denoted by m, the acceleration due to gravity is denoted by the letter g. and the height in meters is denoted by h.

Step 1: Use the potential energy formula to calculate apple mass

Potential energy of an apple PE = 6.0 joules  

Heigh of the apple h = 3m

Acceleration due to gravity   g = 9.8 m/s^2   

PE = mgh

m = \frac{PE}{gh}

m = \frac{6.0 joules }{9.8 m/s^2 *3m}   

[math] m = \frac{2}{9.8} [/mathg] kg

m = 0.2040

Thus, mass of the apple m = 0.20 kg