We use the radioactive decay equation for this problem which is expressed as:
An = Aoe^-kt
An is the remaining amount after time t, Ao is the initial amount and k is a constant.
First, we determine the k from the half life as follows:
An/Ao = 1/2 = e^-k(14.4)
k = 0.04814
Then, we can calculate An after 28.8 yr.
An = 1000 e^-0.04814(28.8)
An = 250 g
Answer:
3300J
Explanation:
Work done is the energy that is lost by the skater
Formula for workdone = 1/2*mV^2
m = 66kg
V = 10m/s
Work done = 1/2 * 66 * 10^2
= 3300J
As we know that total work done by a force is given by
so it is product of force and displacement along same direction
as we can write it as
so it must be the product of force and displacement in same directions so correct answer must be
<u>B. in the same direction as the displacement vector and the motion.</u>
Quisiera ayudarte pero no puedo apenas voy a pasar a secundaria :(
