Answer:
0.0000076 grams
Explanation:
We're given the half life of Tritium to be 12.3 years. In order to find out the amount of substabce remaining:
Let's first find how many 'half lives' are in 250 years.
Now what is half life? It means the time taken for a given quantity of an element to lose half it's mass.
So in 12.3 years we can find that The amount of 250 g of Tritium will be 250/2 = 125 g. In 24.6 years we'll have 125/2 = 62.5 g
So now we can devise a formula:
Where m is the remaining amount and n is th number of half lives in the time given.
Using this formula we can calculate:
Doing this calculation we get:
As we can see a very small value remains.
We can solve the problem by using conservation of momentum.
The player + ball system is an isolated system (there is no net force on it), therefore the total momentum must be conserved. Assuming the player is initially at rest with the ball, the total initial momentum is zero:
The total final momentum is:
where 
is the momentum of the player and 
is the momentum of the ball.
The momentum of the ball is: 
While the momentum of the player is: 
, where M=59 kg is the player's mass and vp is his velocity. Since momentum must be conserved,
so we can write
and we find
and the negative sign means that it is in the opposite direction of the ball.
Answer:
a 15.22 m/s
b 45.65 m
Explanation:
Using the same formula,
x = vt, where
x is now 45.65, and
t is 3 s, then
45.65 = 3v
v = 45.65/3
v = 15.22 m/s
See the attachment for the part b. We used the distance gotten in part B, to find question A
