Gravitational potential energy = mgh or mass times acceleration due to gravity times the height
Here the mass is 0.25kg, the height is 10m, and gravity is 9.8m/s^2 so...
GPE = (0.25)(10)(9.8)
GPE = 24.5 J
I would say B. Because actual mass would ricochet off the sidewalk.
The amount of matter in an object ismass....anything that occupies spaca and has weight is called matter.....