Answer:
fun for kids and family fun
Step-by-step explanation:
Answer:
16.9 m
Step-by-step explanation:
Start with a half a circle. The central angle of a semicircle is 180 deg.
Now subtract 21 deg on each side.
180 - 21 - 21 = 138
The central angle is 138 deg.
The radius is 7 m.
Now we use the formula for the length of an arc of a circle given the radius of the circle and the central angle of the arc.



Mass of electron:9.109 times 10^-31 kg
mass of proton: 1.673 times 10-27
speed of light=3.0 times 10^8
avogadro's number 6.02 times 10^32
planck's constant: 6.63 times 10^-34
just google chem constants sheet