Answer:
Isotopes are atoms of the same element that have different numbers of neutrons but the same number of protons and electrons. The difference in the number of neutrons between the various isotopes of an element means that the various isotopes have different masses.
Answer:

Explanation:
SO in order to calculate the specific latent heat of fusion, you need to remember the formula:

Where
representes the specific latent heart of fusion.
represents the heat energy added, usually represented in kJ
represents the mass of the object, in kg.
Now that we have our formula we just have to put our values into the formula:



SO our answer would be 
The answer would be c as the cart is not in motion therefor ruling out kinetic and it is completely at rest making all of it energy potential