Inductive charging is used to wirelessly charge electronic devices ranging from toothbrushes to cell phones. Suppose the base un
1 answer:
Answer:
Explanation:
The problem must be addressed through the concepts of electromotive force. By Faraday's law it is defined that
Where
Electromotive Force
N = Number of Loops
A = Area
B = Magnetic Field (chaging through the time)
From this equation and our values, we need to find the time, then we re-arrange the equation
Therefore the time required for the magnetic field to decrease to zero from its maximum value is
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a) Average power: 1425 W
b) Instantaneous power at 3.0 sec: 2850 W
Explanation:
a)
The motion of the object along the ramp is a uniformly accelerated motion (because the force applied is constant), so we can use the suvat equation
where
s = 18 m is the displacement along the ramp
u = 0 is the initial velocity
t = 3.0 s is the time taken
a is the acceleration of the object along the ramp
Solving for a,
Now we can apply Newton's second law to find the net force on the object:
This net force is the resultant of the applied force forward () and the component of the weight acting backward (
), so we can find what is the applied force:
where
m = 24 kg is the mass of the object
is the acceleration of gravity
Now we can finally find what is the work done by the applied force, which is parallel to the ramp, therefore:
where s = 18 m is the displacement.
Therefore the average power needed is:
b)
The instantaneous power at any point of the motion is given by
where
is the force applied
v is the velocity of the object
We already calculated the applied force:
While since this is a uniformly accelerated motion, we can find the velocity at the end of the 3.0 seconds using the suvat equation:
And therefore, the instantaeous power at 3.0 sec is:
Learn more about power:
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Answer:
<em>The object could fall from six times the original height and still be safe</em>
Explanation:
<u>Free Falling</u>
When an object is released from rest in free air (no friction), the motion is completely dependant on the acceleration of gravity g.
If we drop an object of mass m near the Earth surface from a height h, it has initial mechanical energy of
When the object strikes the ground, all the mechanical energy (only potential energy) becomes into kinetic energy
Where v is the speed just before hitting the ground
If we know the speed v is safe for the integrity of the object, then we can know the height it was dropped from
Solving for h
If the drop had occurred in the Moon, then
Where hM, vM and gM are the corresponding parameters on the Moon. We know v is the safe hitting speed and the gravitational acceleration on the Moon is g_M=1/6 g
This means the object could fall from six times the original height and still be safe
Answer:
<em>Correct option: Mohammed has less kinetic energy than Autumn.</em>
Explanation:
<u>Kinetic Energy</u>
Is the energy an object has due to its motion. If the object has a mass m and travels at a speed v, then the kinetic energy K is:
The information about four students includes their mass and velocity as follows:
Autumn has a mass of m1=50 kg and a velocity (magnitude) of v1=4 m/s, thus their kinetic energy is:
Mohammed has a mass of m2=57 kg and a velocity (magnitude) of v2=3 m/s, thus their kinetic energy is:
Lexy has a mass of m3=53 kg and a velocity (magnitude) of v3=2 m/s, thus their kinetic energy is:
Chiang has a mass of m4=64 kg and a velocity (magnitude) of v4=5 m/s, thus their kinetic energy is:
Sorted from lower kinetic energy to higher:
Lexy, Mohammed, Autumn, Chiang. Thus:
Autumn has more kinetic energy than Chiang. False
Mohammed has less kinetic energy than Autumn. True
Lexy has more kinetic energy than Mohammed. False
Chiang has less kinetic energy than Lexy. False
Correct option: Mohammed has less kinetic energy than Autumn.