Answer:
The time take is 
Explanation:
From the question we are told that
The decay constant is
The percentage fall is 
The equation for radioactive decay is mathematically represented as

Where is
is the new amount of the new the isotope while
is the original
At initial
% = 1
At
% = 0.80

=> 
=> 
Answer:
We first to know that if the wheel rotates from rest means that at t=0 the velocity and the angle rotated is 0.
Then, we know:

Integrating 2 times, we have:

For the first 27.9 s, we have:
w = 37.107 rad/s
angle = 517.6426 rad
For the next seconds, according to the text, the angular velocity is constant so
w = 37.107 rad/s and hence, integrating:

Then, the time remaining is:
53.5 - 27.9 = 25.6
So for the next 25.6 seconds we have:

Finally, we add the 2 angles and we have as a result:

<span>Plasma is a controllable reactive gas that is used to make small PATTERNS in silica which are used in computers and cell phones.</span>
The required initial velocity that will result if a projectile lands at the same height from which it was launched is V₀ = V cosθ
First, we must understand that the component of the velocity along the vertical is due to maximum height achieved and expressed as usin
θ.
The component of the velocity along the horizontal is due to the range of the object and is expressed as ucosθ.
If the <u>air resistance is ignored</u>, the velocity of the object will be constant throughout the flight and the initial velocity will be equal to the final velocity.
Hence the required initial velocity that will result if a projectile lands at the same height from which it was launched is V₀ = V cosθ
Learn more here; brainly.com/question/12870645
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