<span>The difference between work done by the gravitational force on descending and ascending objects is that for descending objects a terminal velocity will be reached where the object will not fall any faster that it already is. For an ascending object, its velocity will come down the longer gravity has an effect on it until the object begins to descend and the velocity of an ascending object will continue to change the longer gravity has an effect on it.</span>
Answer:
<em>380 kHz</em>
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Explanation:
The speed of sound is taken as 1500 m/s
The length of the fetus is 1.6 cm long
The condition is that the wavelength used must be at most 1/4 of the size of the object that is to be imaged.
For this 1.6 cm baby, the wavelength must not exceed
λ = 
of 1.6 cm = x 1.6 cm = 0.4 cm =
0.4 cm = 0.004 m this is the wavelength of the required ultrasonic sound.
we know that
v = λf
where v is the speed of a wave
λ is the wavelength of the wave
f is the frequency of the wave
f = v/λ
substituting values, we have
f = 1500/0.004 = 375000 Hz
==> 375000/1000 = 375 kHz ≅ <em>380 kHz</em>
P=IV
V=IR
P=I(IR)
P=I²R
375=5²R
R=375/25
R=15
Time = distance / speed
T = 125/ 5
T = 25 meters per second
Answer:
Force A=-−2,697.75 N
Force B=13, 488.75 N
Explanation:
Taking moments at point A, the sum of clockwise and anticlockwise moments equal to zero.
25 mg-20Fb=0
25*1100g=20Fb
Fb=25*1100g/20=1375g
Taking g as 9.81 then Fb=1375*9.81=13,488.75 N
The sum of upward and downward forces are same hence Fa=1100g-1375g=-275g
-275*9.81=−2,697.75. Therefore, force A pulls downwards
Note that the centre of gravity is taken to be half the whole length hence half of 50 is 25 m because center of gravity is always at the middle
