Answer:
Correct answer: v = 34.98 m/s
Explanation:
The kinetic energy formula is Ek = m v²/2 => v = √2Ek/m
v = √2 · 88.7 / 0.145 = 34.98 m/s
God is with you!!!
Answer:
for 
Where z=0 m is the position of Miss Piggy and z=4 m is the position of the speaker.
Explanation:
Assuming that Miss Piggy emits a sound wave that is in phase with the speaker, and that z=0 is the position of Miss Piggy and z=4 is the position of the speaker, we would have a superposition of two traveling sound waves. Furthermore let's assume that both waves have the same amplitude. The total resulting wave will be given by:
where 
is the angular frequency of the traveling wave and 
is the wave number defined as 
. 
is the wavelength of both traveling waves (they have the same wavelength because they have the same frequency). 
where v is the speed of sound.
By using the trigonometric identity 
we can rewrite 
as
.
In order for the resulting wave to have maximum destructive interference, that is to be zero for any time t, we need to have
Only first is kinetic.
So 2-3-4 are not
Answer:
Spinning permanent magnets within an array of fixed permanent magnets.
Explanation:
Any relative motion between magnets (be they permanent or electromagnetic) and a coil of wire will induce an electric current in the coil.
What will not induce an electric current is the relative motion between the two coils of wire (because there is no change in magnetic field), or the relative motion between two magnets (there are no coils of wire to induce the current into).
Therefore, spinning permanent magnets within an array of fixed permanent magnets does not induce an electric current.
<em>In all other choices, coils of wire are there to be induced current into, and magnets are present to create changing magnetic fields. </em>
