Answer:
it states that energy can either be gained or lost but it only changes its form.
Explanation:
for example:as a ball is still on the table it posses a potential energy of 100j and a k.e of 0j,as it falls it gains k.e so the midpoint the p.e is equal to the k.e (50j equally) as it approches the ground it completely gains k.e (100j) and the p.e is 0j.
total energy is 100j so it has been converted from p.e to k.e.
hope u have understood.
