Answer:
<u>Option "C":</u> "4.5 g"
Explanation:
N0 = 36 g, Let half-life is T.
t = 3 T, n is number of half lives = t / T = 3
<u>By using the decay law of radioactivity</u>
N / N0 = (1 / 2)^n
where
"N0" be the "initial amount"
"N" be the "amount left"
"n" be the "number of half-lives"
N / 36 = (1/2)^3
N / 36 = 1 / 8
N = 36 / 8 = 4.5 g
a) 120 s
b) v = 0.052R [m/s]
Explanation:
a)
The period of a revolution in a simple harmonic motion is the time taken for the object in motion to complete one cycle (in this case, the time taken to complete one revolution).
The graph of the problem is missing, find it in attachment.
To find the period of revolution of the book, we have to find the time between two consecutive points of the graph that have exactly the same shape, which correspond to two points in which the book is located at the same position.
The first point we take is t = 0, when the position of the book is x = 0.
Then, the next point with same shape is at t = 120 s, where the book returns at x = 0 m.
Therefore, the period is
T = 120 s - 0 s = 120 s
b)
The tangential speed of the book is given by the ratio between the distance covered during one revolution, which is the perimeter of the wheel, and the time taken, which is the period.
The perimeter of the wheel is:
where R is the radius of the wheel.
The period of revolution is:
Therefore, the tangential speed of the book is:
The answer is B.)
This is because for years scientists have build up and found discoveries that led to recent discoveries brought by previous scientists.
Hope this helps
Answer:
The correct answer is 'A'
Explanation:
I guessed and was correct.
Answer:
1) John's ball lands last.
2) All three have the same total energy
Explanation:
John's ball will land last because his ball was projected at the largest angle. This means that the ball will spend more time in the air when compared to the other balls.
The total energy in a projected particle is the sum of its kinetic energy (0.5mv^2) and its potential energy due to its height (mgh). The total kinetic energy can be as a result of both, or at times fully transformed to either of the energy. For example, at the maximum height, the kinetic energy of John's ball is zero and is fully transformed into potential energy due to that height, whereas George's ball will mostly posses kinetic energy and a little potential energy. The three ball are assumed to have the same properties and are projected with the same initial velocity. This means that they all have the same kinetic energy at the instance of projection which can then be transformed into potential energy, or maintained as a combination of both throughout the flight or simply transformed into potential energy, but the total energy is always conserved.