The answer is C guide and inspire good conduct
Answer:
t = 5.59x10⁴ y
Explanation:
To calculate the time for the ¹⁴C drops to 1.02 decays/h, we need to use the next equation:
(1)
<em>where
: is the number of decays with time, A₀: is the initial activity, λ: is the decay constant and t: is the time.</em>
To find A₀ we can use the following equation:
(2)
<em>where N₀: is the initial number of particles of ¹⁴C in the 1.03g of the trees carbon </em>
From equation (2), the N₀ of the ¹⁴C in the trees carbon can be calculated as follows:
<em>where
: is the tree's carbon mass,
: is the Avogadro's number and
: is the ¹²C mass. </em>
Similarly, from equation (2) λ is:
<em>where t 1/2: is the half-life of ¹⁴C= 5700 years </em>

So, the initial activity A₀ is:
Finally, we can calculate the time from equation (1):
I hope it helps you!
Answer: 27 joules
Explanation:
Work is done when force is applied on the bench over a distance. it is measured in joules.
Workdone = force x distance
= 45 N x 0.6 metres
= 27 joules
Thus, 27 joules of work is done on the bench.