Answer:
3
Explanation:
The half-life of a radioactive isotope is the time it takes for the mass of the sample to halve.
This can be rewritten as follows:
where
m(t) is the mass of the sample at time t
m0 is the original mass of the sample
n is the number of half-lives that passed
We see that if we take n=3, the amount of original sample left is
So 3 (3 half-lives) is the correct answer.
The speed of the brick dropped by the builder as it hits the ground is 17.32m/s.
Given the data in the question;
Since the brick was initially at rest before it was dropped,
- Initial Velocity;
- Height from which it has dropped;
- Gravitational field strength;
Final speed of brick as it hits the ground; 
<h3>Velocity</h3>
velocity is simply the same as the speed at which a particle or object moves. It is the rate of change of position of an object or particle with respect to time. As expressed in the Third Equation of Motion:
Where v is final velocity, u is initial velocity, h is its height or distance from ground and g is gravitational field strength.
To determine the speed of the brick as it hits the ground, we substitute our giving values into the expression above.
Therefore, the speed of the brick dropped by the builder as it hits the ground is 17.32m/s.
Learn more about equations of motion: brainly.com/question/18486505
If the mass of the sun is 1x, at least one planet will fall into the habitable zone. if I place a planet in orbits 1, 3, 5 , 6 and all planets will orbit the sun successfully.
<h3>
What are planets?</h3>
Planets are the large spherical shaped objects that rotate about the Sun in the elliptical orbits.
Planets are shaped from Planetary cloud. The dust storm and gases gathers under its own weight. The dense matter beginnings pivoting at high paces and accumulates more mass. The center structures, the star and rest of it ultimately levels into a curved plate from which planet is formed.
Thus, if I place a planet in orbits 1, 3, 5 , 6 and all planets will orbit the sun successfully.
Learn more about planets.
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First, find the amount of time for the dart to hit the board using this equation: t = d/v
t = 2 m/ 15 m/s = 0.133 s
Then, find the height the dart has fallen from its initial point using this equation: h = 0.5gt²
h = 0.5(9.81 m/s²)(0.133 s)² = 0.0872 m or 8.72 cm
Since the diameter of the bull's eye is only 5 cm, and you started at the same level of the top of the bull's eye, that means the maximum allowance would only be 5 cm. Since it exceeded to 8.72 cm, it means that <em>Veronica will not hit the bull's eye.</em>
