Answer:
iv) It is 9x bigger than before
Explanation:
As the amplitudes of the new speakers add directly with the original one, taking into account the phase that they have, the composed amplitude of the sound wave is as follows:
At = A + 4A -2A = 3 A
The intensity of the wave, assuming it propagates evenly in all directions, is constant at a given distance from the source, and can be expressed as follows:
I = P/A
where P= Power of the wave source, A= Area (for a point source, is equal to the surface area of a sphere of radius r, where is r is the distance to the source along a straight line)
For a sinusoidal wave, the power is proportional to the square of the amplitude, so the intensity is proportional to the square of the amplitude also.
If the amplitude changes increasing three times, the change in intensity will be proportional to the square of the change in amplitude, i.e., it will be 9 times bigger.
So, the statement iv) is the right one.
Answer:
The energy lost is 0.333156518 J.
Explanation:
The given mass of the pendulum = 0.259 kg
Length = 0.97 m
Displaced at an angle of = 31.4 degrees
Maximum angle of swing = 10 degrees
Initial potential energy = mgh
Initial potential energy = 0.259 × 9.8 × (1 – cos31.4)
= 0.259 × 9.8 × ( 1- 0.853551)
= 0.371716852 J
Final potential energy = mgh
Final potential energy = 0.259 × 9.8 × (1 – cos10)
= 0.259 × 9.8 × (1 – 0.984808)
= 0.0385603344 J
The lost energy = Initial potential energy - Final potential energy
= 0.371716852 J - 0.0385603344 J
= 0.333156518 J
Two examples of where you can find permanent magnets are
1.compass
2.speakers
Answer:
Acceleration is the rate of change in velocity. Momentum is the mass times the velocity. So if you multiply the mass times the acceleration, you get the of change of momentum.
Answer:
the answer is B 80turns
Explanation:
Hello!
Remember that a transformer is an electrical device that allows you to change the voltage and current levels keeping the electric power constant, in this order of ideas the equation that governs this device is as follows
where
Vp= primary voltage=120V
Vs= secondary voltage=1200V
Ns=turns of secondary=800
Np=turns of primary
now we solve for Np
the answer is B 80turns