Answer:
127.5 J
Explanation:
Potential energy is given as the product of mass of an object, the height moved and acceleration due to gravity. Therefore, PE=mgh
The change in potential energy is given by mg(hf-hi) where hf-hi is change in height got by subtracting initial height from final height. In this case, the initial height is zero while final height is 1.78 m.
Substituting 9.81 m/s2 for g, 7.3 kg for m and h with 1.78 then the change in potential energy will be
7.3*9.81*(1.78-0)=127.47114 J
Rounded off as 127.5 J
