Answer:
proof in explanation
Explanation:
First, we will calculate the number of half-lives:

where,
n = no. of half-lives = ?
t = total time passed = 2100 million years
= half-life = 700 million years
Therefore,

Now, we will calculate the number of uranium nuclei left (
):

and the rest of the uranium nuclei will become thorium nuclei (
)

dividing both:

<u>Hence, it is proven that after 2100 million years there are seven times more thorium nuclei than uranium nuclei in the rock.</u>
Answer:
Water temperatures are slow to heat up, It takes 4 times the energy to heat up water than to heat air. Water also "feels" colder because water is a more efficent medium than air to cool our body down.
Re word it tho
Hope this helps!!
Answer:
acceleration or a deceleration
Explanation:
The gradient of a position - time graph represent the velocity.
a straight line indicate a constant velocity (gradient ≠ 0)
when it is a parallel line to the time axis , it indicated no movement
when it is a curved line it indicates a changing velocity (either acceleration or a deceleration) as mentioned in the graph