a boeing 747 has a total mass, including passengers and luggage, of 250,000 kg. How much force do the engines supply to achieve a take off velocity of 990 m/s in 35 seconds.
Answers
Acceleration = (change in speed) / (time for the change)
Acceleration = (990 m/s) / (35 sec) = 28.29 m/s²
Force = (mass) x (acceleration)
Force = (250,000 kg) x (28.29 m/s²) = 7.07 million Newtons
about 1.59 million pounds .
===========================================
There you have the Physics and the Math.
Does any of this resemble the real world ?
No. The question is completely bogus.
-- Take-off speed can't be 990 m/s.
That would be about 2,200 mph, almost 3 times the speed of sound.
-- The take-off run can't accelerate at 28.3 m/s² .
That would be almost 3 G's. If it didn't rip the wings off of the 747,
it would surely guarantee early use of most of the passengers' barf bags.
-- The Saturn V first-stage booster that sent Apollo to the moon
had a thrust of 7.5 million pounds. I'm pretty sure that was more
than 4.7 Boeing 747's.
================================
Ah hah ! I've just been handed a bulletin, or as they say nowadays,
there is breaking news !
I see that the take-off speed has been revised downward to 90 m/s.
That's right at 200 mph which seems reasonable to me, so let's go
back and do the whole thing again:
Acceleration = (change in speed) / (time for the change)
Acceleration = (90 m/s) / (35 sec) = 2.57 m/s² (about 0.26 G)
Force = (mass) x (acceleration)
Force = (250,000 kg) x (2.57 m/s²) = 643 thousand Newtons
about 144 thousand pounds.
about 1.9% of a Saturn V booster.
I like that a lot better.
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A papyrus scroll has 90% of the initial 14C present in it today. How old is the scroll if the half-life for 14 C is 5730 years? O 8230 years O 41.5 years O 871 years O 18.0 years O 38,100 years
Answers
Answer:
the magnet or electric current produces a magnetic field
Explanation:
this magnetic field can be visualized as a pattern of a circular field lines surrounding a wire. hall probes can determine the magnitude of the field
hope it helps you
wave in medium A, the wave in medium B has
(1) half the speed
(2) twice the speed
(3) half the frequency
(4) twice the frequency
Answers
Final answer:
The situation described in the question pertains to wave propagation. Given that wave speed in a given medium is constant, and the relationship between wave speed, wavelength, and frequency, the wave in medium B, which has double the wavelength of the wave in medium A, would have half the frequency of the wave in medium A.
Explanation:
This question is about wave propagation between two different mediums, labeled 'A' and 'B'. The fundamental principle involved here is the dependence of wave speed on the medium through which it travels. However, it's necessary to recognize that wave speed also depends on wavelength and frequency. This relationship is encapsulated by the formula v = fλ, where v is wave speed, f is frequency, and λ is wavelength.
From the problem statement, we understand that the wavelength doubles when going from medium A to medium B. We are then asked to deduce the corresponding change in wave speed or frequency. If the wavelength doubles and the wave speed remains the same, the only possible adjustment is for the frequency to halve. So, the wave in medium B, compared to the wave in medium A, would have half the frequency (3). This is because wave speed in a given medium is constant and as per the formula, if wavelength increases, frequency must decrease.
Learn more about Wave Propagation here:
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1/2w + 7 = 2w - 2
Answers
First, replace the numerator with 'w'.
Second, multiply both sides by 2.
Third, subtract 'w' from both sides.
Fourth, simplify to 3w - 4.
Fifth, add '4' to both sides.
Sixth, add 14 + 4.
Seventh, divide both sides by '3'.
Eighth, since 6 goes into 3 to get 18, simplify the fraction to 6.
Ninth, switch the sides.
Answer: w = 6
gravity
friction
weight
Answers
The Correct Answer Is Friction.
Answers
Final answer:
The SI base unit for mass is the kilogram (kg), which is defined as the mass of a specific reference object. The gram (g) is a smaller unit of mass, equal to 1/1000 of a kilogram.
Explanation:
The SI base unit for mass is the kilogram (kg). It is defined as the mass of a specific reference object, which was originally one liter of pure water. In May 2019, the definition was changed to be based on fundamental physical constants. The gram (g) is a smaller unit of mass, equal to 1/1000 of a kilogram.
Learn more about kilogram here:
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Answers
Answer:
Option "D" is the correct answer i.e. Both Technicians A & B
Explanation:
Dear,
Loose wheel bearings can be caused on any machine.
The Following can be the reasons :
- the machine or motor is installed improperly
- the rotor(rotating part) of machine is not balanced
- the cover get deteriorated with time
- Bad manufacturer
So, when the bearings will be loose then the following can happen:
- It will produce vibration in machine which can be judged by a vibration pen eg. SKF vibration pen
- The vibration will also result in noise. You can check by
- The machine winding if it is motor will burn-out.
- Bush needs to be installed if the bearing runs loose.
Therefore, "D" is right.