Answer : The time passed in years is 20.7 years.
Explanation :
Half-life = 28.1 years
First we have to calculate the rate constant, we use the formula :



Now we have to calculate the time passed.
Expression for rate law for first order kinetics is given by:

where,
k = rate constant = 
t = time passed by the sample = ?
a = initial amount of the reactant = 1.00 g
a - x = amount left after decay process = 0.600 g
Now put all the given values in above equation, we get


Therefore, the time passed in years is 20.7 years.
Answer:
12000 miles per hour
Explanation:
If skid Marx went from zero to 10 miles in 3 seconds the his speed would have been 12000 miles per hour.
Answer:

Explanation:
We are given that
Atomic number=2
We have to find the total negative charge on the electrons in one mole of Helium.
We know that atomic number=Proton number
Proton number=Number of electrons=2
Number of electrons in Helium=2
1 mole of Helium=
atoms
We know that q=ne
Where n =Number of fundamental units
e=Charge on electron
1 e=
Using the formula

Total negative charge in 1 mole=
Hence, the total negative charge on the electrons in 1 mole of Helium=
Answer: 13%
Explanation: The reason this is 13 is because you can eat carlories and you can also be an amazing person 200 calories and 7 grams
When firing straight up:
v^2 = u^2 - 2gh, where v = final velocity = 0, u = initial velocity, g = gravitational acceleration, h = maximum height attained.
Then,
0 = u^2 - 2gh
u = Sqrt (2gh) ---- (1)
When firing at 45°,
Initial velocity, U = u Sin 45 = Sqrt (2gh)·Sin 45
Maximum height, H = U^2*(Sin Ф)^2/2g
substituting;
H = [Sqrt (2gh)·Sin 45]^2*(Sin 45)^2]/2g
H = [2gh*(Sin 45)^2*(Sin 45)^2]/2g
H = [h*(Sin 45)^4] = h/4
Therefore, maximum height when the gun fires at 45° is a quarter of maximum height when the gun fires vertically up.