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>
Volume = l*w*h = (18.1 cm)(19.2 cm)(20.3 cm) = 7,054 cm^3.
Condensation. Remember, Vaporization happens when energy is taken in (enfothermic) the opposite will be the process that releases energy ( exothermic) which will be condensation. Put ice in a glass of water. the ice melts, taking in energy from the water in the glass, which in turn takes heat energy away from the vapor in the surrounding air, thus causing the water vapor in the air to condense.
Answer:
0.67 s
Explanation:
This is a simple harmonic motion (SHM).
The displacement,
, of an SHM is given by

A is the amplitude and
is the angular frequency.
We could use a sine function, in which case we will include a phase angle, to indicate that the oscillation began from a non-equilibrium point. We are using the cosine function for this particular case because the oscillation began from an extreme end, which is one-quarter of a single oscillation, when measured from the equilibrium point. One-quarter of an oscillation corresponds to a phase angle of 90° or
radian.
From trigonometry,
if A and B are complementary.
At
, 


So

At
, 





The period,
, is related to
by

Answer:
B. less
Explanation:
acceleration due to gravity on Earth, g = 9.8 m/s²
acceleration due to gravity on Moon, g = 1.6 m/s²
Given mass of the object as, m = 5 kg
Weight of an object is given as, W = mg
Weight of the object on Earth, W = 5 x 9.8 = 49 N
Weight of the object on Moon, W = 5 x 1.6 = 8 N
Therefore, the object weighs less on the moon compared to its weight on Earth.
The correct option is "B. less"