Answer:

Explanation:
When adding or subtracting values, you must round your answer to the same "place" as the measurement with its last significant figure furthest to the left.
That is, you round off to the same number of decimal places as the measurement with the fewest decimal places.

The measurements of 14.0 and 10.6 have one digit after the decimal point, so you round the sum to have only one digit to the right of the decimal.
The number to be dropped (3) is less than 5, so you drop it.

Answer:
length of wire = 38.82 m
Explanation:
∴ 16 gauge ≡ 0.05082 in * ( 2.54 cm/in ) = 0.12908 cm
∴ m spool = 1 Lb = 453.592 g
∴ ρ = 8.92 g/cm³
cross section area:
⇒ A = π*D²/4 = π*(0.12908)²/4 = 0.0131 cm²
⇒ L = ((453.592 g) *(cm³/8.92 g)) / ( 0.0131 cm² )
⇒ L = 3881.765 cm * ( m/100cm) = 38.82 m
Physical change: a change in which no new substances are formed. the form of the substance is changed but not it's chemical composition (ice melting, bread toasting)
chemical change: any change that results in the formation of new chemical substances. this type of change modifies molecules and atoms by making and breaking the bonds between atoms! (iron rusting, gas burning)
so basically a physical change just changes the appearance of a substance, but a chemical change changes the makeup on a molecular level. i hope this helps you out!
4. Just add the protons and neutrons together.