Neon has two isotopes: Ne-20 (having a frequency of 90%) and Ne-22 (having a frequency of 10%). Given the following abundances of these isotopes in nature, what is the average
atomic mass of neon?
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If two parallel light rays hit a mirror, they will not be parallel to each other after they reflect.

Aplayground slide is 8.80 ft long and makes an angle of 25.0° with the horizontal. a 63.0-kg child, initially at the top, slides all the way down to the bottom of the slide. (a) choosing the bottom of the slide as the reference configuration, what is the system's potential energy when the child is at the top and at the bottom of the slide? what is the change in potential energy as the child slides from the top to the bottom of the slide? (include the sign of the value in your answer.)

The gun from the crime scene shows tool marks where the serial numbers are ground off. there are also tool marks on the bullets left behind. what information can the tool marks on the bullets and gun provide about the crime? what type of evidence does this information provide, individual or class?