Answer:
E= 2 J
Step-by-step explanation:
For this case we see how the mechanical energy is generated by the potential energy due to the change of position. We can express that as
E=m*g*h
Being "m" the mass of the object, "g" the value of the acceleration by gravity and "h" the distance traveled in the movement. So
E=m*g*h=0.8Kg*10m/s2*(0.75-0.5)=2J
Done