Im guessing it's (a) since the numbers go in chronological order and you read the periodic table left to right
Answer:C
Explanation:
Mass energy of hydrogen fusing into helium
Answer:
A sample of 5.2 mg decays to .65 mg or to 1/8 of its original amount.
1/8 = 1/2 * 1/2 * 1/2 or 3 half-lives.
3 * 30.07 = 90 yrs for 5.2 mg to decay to .65 mg
You can get these other numbers similarly:
5.2 / .0102 = 510 requires about 9 half-lives which is 30 * 9 = 270 yrs
We use the equation of motion,

Here, S is the height, u is initial velocity and a is acceleration.
Given,
As acorn falls from tree, therefore we take the value of
and initial velocity
.
Substituting these values in equation of motion,

Thus, the time taken by the acorn to fall 20 feet ( 6.096 m ) is 1.12 s.