Karl Kruszelnicki has insisted the reason why so many ships and planes vanish without trace in the area between Bermuda, Florida, Puerto Rico is nothing to do with aliens or fire-crystals from the lost city of Atlantis.
Instead, the Australian scientist ‘revealed’, the high number of disappearances is explained by nothing more supernatural than plain old human error plus bad weather and the fact that lots of planes and ships enter that area of the Atlantic Ocean in the first place.
When landing after a spectacular somersault, a 40.0-kg gymnast decelerates by pushing straight down on the mat. Calculate the force she must exert if her deceleration is 7.00 times the acceleration due to gravity. Explicitly show how you follow the steps in the Problem-Solving Strategy for Newton’s laws of motion.
Answer:
[tex]F=3139.2N[/tex]
Explanation:
Mass [tex]m=40.0kg[/tex]
Acceleration [tex]a=7g=68.67m/s^2[/tex]
With g as 9.81
Generally the equation for Force is mathematically given by
[tex]F_net=F-w\\\\F-w=ma\\\\F=ma-w\\\\[/tex]
[tex]F=ma-mg\\\\F=m(a+g)[/tex]
Therefore
[tex]F=m*8g[/tex]
[tex]F=40*8*9.81[/tex]
[tex]F=3139.2N[/tex]
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Answer:
ok
Explanation:
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Two identical satellites orbit the earth in stable orbits. Onesatellite orbits with a speed vat a distance rfrom the center of the earth. The second satellite travels at aspeed that is less than v.At what distance from the center of the earth does the secondsatellite orbit?At a distance that is less than r.At a distance equal to r.At a distance greater than r.Now assume that a satellite of mass m is orbiting the earth at a distance r from the center of the earth with speed v_e. An identical satellite is orbiting the moon at thesame distance with a speed v_m. How does the time T_m it takes the satellite circling the moon to make onerevolution compare to the time T_e it takes the satellite orbiting the earth to make onerevolution?T_m is less than T_e.T_m is equal to T_e.T_m is greater than T_e.
Answer:
a. At a distance greater than r
b. T_m is greater than T_e.
Explanation:
a. Two identical satellites orbit the earth in stable orbits. One satellite orbits with a speed vat a distance r from the center of the earth. The second satellite travels at a speed that is less than v. At what distance from the center of the earth does the second satellite orbit?
Since the centripetal force on any satellite, F equals the gravitational force F' at r,
and F = mv²/r and F' = GMm/r² where m = mass of satellite, v = speed of satellite, G = universal gravitational constant, M = mass of earth and r = distance of satellite from center of earth.
Now, F = F'
mv²/r = GMm/r²
v² = GM/r
v = √GM/r
Since G and M are constant,
v ∝ 1/√r
So, if the speed decreases, the radius of the orbit increases.
Since the second satellite travels at a speed less than v, its radius, r increases since v ∝ 1/√r.
So, the distance the second satellite orbits is at a distance greater than r
b. An identical satellite is orbiting the moon at the same distance with a speed v_m. How does the time T_m it takes the satellite circling the moon to make one revolution compare to the time T_e it takes the satellite orbiting the earth to make one revolution?
Since the speed of the satellite, v = √GM/r where M = mass of planet
Since the satellite is orbiting at the same distance, r is constant
So, v ∝ √M
Since mass of earth M' is greater than mass of moon, M", the speed of satellite circling moon, v_m is less than v the speed of satellite circling earth at the same distance, r
Now, period T = 2πr/v where r = radius of orbit and v = speed of satellite
Since r is constant for both orbits, T ∝ 1/v
Now, since the speed of the speed of the satellite on earth orbit v is greater than the speed of the satellite orbiting the moon, v_m, and T ∝ 1/v, it implies that the period of the satellite orbiting the earth, T_e is less than the period of the satellite orbiting the moon, T_m since there is an inverse relationship between T and v. T_e is less T_m implies T_m is greater than T_e
So, T_m is greater than T_e.
Một electron di chuyển theo đường tròn vuông góc từ trường đều 2 mT. Nếu tốc độ của electron là 1,5×〖10〗^7 ∕〖 〗, hãy xác định
bán kính của đường tròn và
khoảng thời gian cần thiết để electron di chuyển hết vòng tròn.
Answer:
can u translate in English?
Explanation:
if u mind please it would help alot
A car moves at a constant speed of 90km/h from a starting point. Another car moves at 70km/h after 2hours from the same starting point. if both cars moves in the same direction, after how many hours will the distance between the first car and the second car to be 40 km.
Answer:
400
Explanation:
If 1.02 ✕ 1020 electrons move through a pocket calculator during a full day's operation, how many coulombs of charge moved through it?
Answer:
Explanation:
one electron has [tex]1.60217662*10^{-19}~coulombs~then\\\\1.02*10^{20}~electrons------->1.02*10^{20}*1.60217662*10^{-19}~coulombs= 16.3422~coulombs[/tex]
Three people are trying to move a box. Which set of forces will result in a net
force on the box of 20 N to the left?
Answer:
yes the answer is D as the two people if we calculate
Answer:
A
Explanation:
correct on A P E X
Necesito ayudaaaaaa por favor
MAnswer:
Explanation:
(1) Define uniform acceleration
Answer:
Explanation:
When an object's speed increases at a constant rate, we say it has constant/uniform acceleration.
can Denel be regarded as monopoly in south africa
Answer:
Denel (Pty) Ltd was established as a private company, incorporated in terms of the Companies Act on 1 April 1992 with the State as the sole shareholder. ... Denel can at present, without doubt, be regarded as a public monopoly.
please someone help I have to hand this in asap
I will give u 5 stars all that - give steps if u can
Explanation:
the answer is in the above image
why are cows is important?
Answer:
cause they give u milk
Explanation:
Answer:
Cows are important as they provide humans many things for survival. They provide milk, meat, and leather, all of these are important resources.
If the pressure of a gas is really due to the random collisions of molecules with the walls of the container, why do pressure gauges – even very sensitive ones – give perfectly steady readings? Shouldn't the gauge be continually jiggling and fluctuating? Explain.
Answer:
there is no fluctuation in the measurement because the quantity of molecule is too large and a quantity of some molecules is imperceptible.
Explanation:
The pressure measurement is carried out by calibrating the force exerted by the air on a surface of known area, suppose a small area 1 mm² = 0.01 cm²
To find out if the random movement of air molecules affects the pressure reading, let's calculate the number of molecules that reaches the pressure gauge.
In a system at atmospheric pressure and in a volume of 1 m³ (walls of 1 m each) there is one mole of air molecules, this mole is evenly distributed, so how many molecules fall on our surface
# _molecule = 6.02 10²³ 0.01 10⁻⁴ / 1
#_molecular = 6.02 10¹⁷ molecules per second
therefore the variation of the number of molecules is not very important
Consequently there is no fluctuation in the measurement because the quantity of molecule is too large and a quantity of some molecules is imperceptible.
The efficiency of a machine can be increased by
Explanation:
the efficiency of a machine can be increased by reducing the friction
please mark the brainliest
Select the correct answer from each drop-down menu.
Balloon B is negatively charged.
Balloon A is ( )
charged, and balloon C is( ) charged. If balloon A approaches balloon C, there'll be a force of ( )
between them.
Answer:
it would look like what I did in the picture
Explanation:
The latent heat of vaporization of water is roughly 10 times the latent heat of fusion of water. The amount of heat required to boil away 1 kg of water is __________ the amount of heat required to melt 1 kg of ice.
Answer:
The amount of heat required to boil away 1 kg of water is 10 times the amount of heat required to melt 1 kg of ice
Explanation:
let the latent heat of fusion of ice = L
then, the latent heat of vaporization of water = 10L
The heat of fusion of 1 kg of ice = 1 x L = L
The heat of vaporization 1 kg of water = 1 x 10L = 10L
Therefore, the amount of heat required to boil away 1 kg of water is 10 times the amount of heat required to melt 1 kg of ice
Some scientists hypothesize that icy debris arrived on other terrestrial planets in a similar manner to how it arrived on Earth. On Earth, the ice eventually turned to water and water vapor, forming extensive oceans and a life-sustaining atmosphere. But the same is not exactly true for the other terrestrial planets. What are two reasons why?
Temperatures on Earth are ideal for water to exist in solid, liquid, and gaseous forms.
Magnetic forces generated in Earth’s mantle are directly responsible for Earth’s oceans.
Earth’s gravity holds the water vapor in Earth’s atmosphere close to its surface.
Earth’s solid outer core is sufficiently rigid to keep water above its surface.
Answer:
Temperatures on Earth are ideal for water to exist in solid, liquid, and gaseous forms.
Earth's gravity holds the water vapor in Earth's atmosphere close to its surface.
Answer: a and c
Explanation:
from plato
15. A car travelling towards the right has a mass of 1332 kg and has a speed of 25 m/s. A truck is
travelling towards the left with a mass of 3000 kg and a speed of 15 m/s. They collide head
on with each other. What is the total momentum after the crash? In which direction will the
vehicles travel after the collision?
Explanation:
Given that,
The mass of a car, m₁ = 1332 kg
The speed of the car, u₁ = 25 m/s (right)
The mass of a truck, m₂ = 3000 kg
The speed of the truck, u₂ = -15 m/s
The total momentum after the crash is given by :
p=m₁u₁ + m₂u₂
Put all the values,
P = 1332(25) + 3000(-15)
= −11700 kg-m/s
So, the total momentum after the crash is equal to 11700 kg-m/s and it is in the left direction.
Calculate the period of a spring if it has a mass of 5 kg and a spring constant of 6 N/m
Answer: The period of a spring if it has a mass of 5 kg and a spring constant of 6 N/m is 5.73 sec.
Explanation:
Given: Mass = 5 kg
Spring constant = 6 N/m
Formula used to calculate period is as follows.
[tex]T = 2 \pi \sqrt\frac{m}{k}[/tex]
where,
T = period
m = mass
k = spring constant
Substitute the values into above formula as follows.
[tex]T = 2 \pi \sqrt\frac{m}{k}\\= 2 \times 3.14 \times \sqrt\frac{5}{6}\\= 5.73 s[/tex]
Thus, we can conclude that the period of a spring if it has a mass of 5 kg and a spring constant of 6 N/m is 5.73 sec.
what is kinematics ???
explain !!!
copied answer = 20 answers reported xD
Explanation:
2 one is kinametics
please check attachment
Kinematics is the branch of classical mechanics that describes the motion of points, objects and systems of groups of objects, without reference to the causes of motion (i.e., forces ). The study of kinematics is often referred to as the “geometry of motion.”
A scenario where reaction time is important is when driving on the highway. During the delay between seeing an obstacle and reacting to avoid it (or to slam on the brakes!) you are still moving at full highway speed. Calculate how much distance you cover in meters before you start to put your foot on the brakes if you are travelling 65 miles per hour.
Answer:
66.83 meters
Explanation:
After a quick online search, it seems that scientists calculate the average reaction time of individuals as 2.3 seconds between seeing an obstacle and putting their foot on the brakes. Now that we have this reaction time we need to turn the miles/hour into meters/second.
1 mile = 1609.34 meters (multiply these meters by 65)
65 miles = 104,607 meters
1 hour = 3600 seconds
Therefore the car was going 104,607 meters every 3600 seconds. Let's divide these to find the meters per second.
[tex]\frac{104,607}{3600} = \frac{29.0575 meters}{1 second}[/tex]
Now we simply multiply these meters by 2.3 seconds to find out the distance covered before the driver puts his/her foot on the brakes...
29.0575m * 2.3s = 66.83 meters
According to the model, when was the universe at its most dense?
A) During the Dark Ages where matter increased in mass.
B) Just before the Big Bang where all matter existed in a singularity.
C) During the nuclear fusion events, as the atoms become more massive.
D) Current day, as the number of galaxies, solar systems, and planets have increased.
Answer:
The Answer is D
Explanation:
Hope this helps!!!!
Calculate the height that the ball bounces.
Sketch the position-time graph for the motion of the ball during the 2,89 s.
(Use the ground as zero position)
Show the following on the graph:
The position of the ball at 0 s.
The position of the ball at 0,5 s.
The position of the ball at time ty. how the graph will be?
Answer:
im bouta get 50 points
Explanation:
What is 3*10^-6 divided by 2.5*10^6 expressed in standard notation?
Answer:
1.2 x 10^-12
Explanation:
3/2.5 x 10^-6/10^6
1.2 x 10^-6 x 10^-6
1.2 x 10^-12
why the walls of tyres becomes warm as the car moves
Answer:
the particles vibrate inside the tyre
Explanation:
as the car moves kinetic energy is transfered in the tyres which causes the particles to vibrate inside the tyre so the kinetic store is. transferred into thermal
What is Magnetic field
The area around a magnet in which it's magnetic force can ne experienced.
➛ Magnetic field has both magnitude and direction.
➛ Magnetic field can be described with help of a magnetic compass.
➛ It's SI unit is Tesla( T ) .
Explanation:
An area around a magnet or materials that behave like a magnet, where there is a force that will attract some metals towards it.
[tex] \: [/tex]
how many grams are in 5 kilos
1 kilo = 1000 gms
Therefore, 5 kilo = 5000 gms
A car moving in a straight line uniformly accelerated speed increased from 3 m / s to 9 m / s in 6 seconds. With what acceleration did the car move?
a.
2 m/s2
b.
1 m/s2
c.
0 m/s2
d.
3 m/s2
Answer:
b) 1 m/s
I am sure...........
Calculate the equivalent resistance
For a standard production car, the highest road-tested acceleration ever reported occurred in 1993, when a Ford RS200 Evolution went from zero to 26.8 m/s (60 mi/h) in 3.323 s. Find the magnitude of the car's acceleration.
Answer:
a = 8.06 m/s²
Explanation:
The acceleration of this car can be found using the first equation of motion:
[tex]v_f = v_i + at\\\\a = \frac{v_f-v_i}{t}[/tex]
where,
a = acceleration = ?
vf = final speed = 26.8 m/s
vi = initial speed = 0 m/s
t = time = 3.323 s
Therefore,
[tex]a = \frac{26.8\ m/s-0\ m/s}{3.323\ s}[/tex]
a = 8.06 m/s²
