Answer:
1280 mg
Explanation:
Radioactive decay is a phenomenon that occurs when a certain isotope of an element, said to be radioactive, decays, turning into a lighter nucleus and emitting radiation + energy in the process.
The radioactive decay of this isotope of polonium is described by the equation
where
is the amount of polonium left after time t
is the amount of polonium t time t = 0
is the half-life of the polonium, in days (it is the time it takes for the initial element to halve its amount)
IN this problem, we know that:
After t = 560 days, the amount of polonium left is . Therefore, we can re-arrange the equation, substituting t = 560 d, and solve for to find the initial amount of polonium:
Shooking the rope up and down 5 times per seconds means that there are 5 cycles of the wave (or 5 crests) in one second, and so its frequency is
.
The period T is the reciprocal of the wave's frequency, therefore it is
To solve this problem we will apply the concepts related to centripetal acceleration, which will be the same - by balance - to the force of gravity on the body. To find this acceleration we must first find the orbital velocity through the Doppler formulas for the given periodic signals. In this way:
Here,
Orbital Velocity
Maximal Wavelength
Average Wavelength
c = Speed of light
Replacing with our values we have that,
<em>Note that the average signal is 3.000000m</em>
Now using the definition about centripetal acceleration we have,
Here,
v = Orbit Velocity
r = Radius of Orbit
Replacing with our values,
Applying Newton's equation for acceleration due to gravity,
Here,
G = Universal gravitational constant
M = Mass of the planet
r = Orbit
The acceleration due to gravity is the same as the previous centripetal acceleration by equilibrium, then rearranging to find the mass we have,
Therefore the mass of the planet is
The correct answer is low resistance.
A heating element's resistance is neither "extremely high" nor "very low." Since the amount of heat produced by the circuit is proportional to the current, the resistance of the heating element must be low enough to draw the necessary current. Thus, low resistance is the general characteristic of electrical devices like warmers, toasters, and heating pads. Any voltage will experience high current if resistance is too low. Current will be low if resistance is too high and voltage is okay. NOTE: Current increases as resistance decreases and decreases as resistance increases while the voltage remains constant, like in an automotive circuit.
Learn more about electrical appliances here :-
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Answer:
Acceleration, a = 750m/s²
Explanation:
Given the following data;
Radius, r = 0.31m
Velocity, v = 15m/s
To find the centripetal acceleration;
Substituting into the equation, we have;
Acceleration, a = 750m/s²
Therefore, the centripetal acceleration of the bike wheel is 750m/s².