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!
Part A:
For this part we’re assuming all the kinetic energy of the moving bumper car is converted into elastic potential energy in the spring since the car is brought to rest. Therefore you can find the total kinetic energy to get your answer:
KE = ½ mv^2
KE = ½ (200)(8)^2
KE = 6400 J
Part B:
Now you can use Hooke’s law to find the force:
F = kx
F = (5000)(0.2)
F = 1000 N
Imagine you are in a swimming pool 30m deep. Assuming you know that water is denser than air, you would know that the 30m of water above you will carry more weight, and press down on your body. Say you were in a swimming pool 60m deep, you would be sandwiched between 30m of water pressing down on you, and the upthrust created by the 30m of water below you.
In a building 30m up, the pressure will be regulated, as you are in a building. The floor will be strong enough to support the weight of the body, and the body will not recoil into itself.
Answer:
B. Solids, liquids, and gases.
Explanation:
I have no explanation.
The electromagnetic spectrum includes a continuous spectrum of wavelengths that include:
Radio waves, microwaves, infrared light, visible, ultraviolet, X-rays, gamma rays
The wavelength decreases from radio waves to gamma rays, whereas the energy increases along the same direction.
In the given example, radio waves have a lower energy and higher wavelength than visible light. The latter can be perceived by the human eye, whereas radio waves are not visible to the human eye.
1) They have colors = visible light
2) They can travel in a vacuum = both
3) They have energy = both
4) They’re used to learn about dust and gas clouds = radio waves
5) They’re used to find the temperature of stars = visible light
6)They’re invisible = radio waves