Why should people pay attention to scientists when making decisions?
A. Scientists are always correct.
B. Sclentists are the smartest people.
C. Scientists make the best decisions.
D. Scientists back up their statements with facts.
Answer:
D. Scientist back up their statements with facts.
Explanation:
The majority of the laws, theorems and thesis are base on with experiments. The follow different strategies for confirm the hypothesis with facts, one of the most famous models is the scientific method. That is a way of proof something in a trustworthy.
In the image is the resume about this method (graphical organizer).
A load of 250 kg is hung by a crane's cable. The load is pulled by a horizontal force such that the cable makes a 30 angle to the vertical plane. If the load is in the equilibrium, calculate the magnitude of the tension in the cable
Answer:
1250[tex]\sqrt{3}[/tex]
Explanation:
Let's look at this in a simple manner, because it is.
The crane weights 250Kg. Okay.
Since it is hung, there is the acceleration of gravity being applied on it (10m/s²)
Since F = m * a
F = 250 * 10
F = 2500
Now we know that the downward Force is 2500N.
To find the force that is being applied on that 30° angle, we can multiply our 2500N by cos30°, which happens to be [tex]\frac{\sqrt{3}}{2}[/tex].
Therefore, the force pulling the box in the cable's direction is:
[tex]\frac{2500\sqrt{3} }{2} = 1250\sqrt{3}[/tex]
If you have any questions feel free to comment.
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A mass is placed at the end of a spring. It has starting velocity of V & allowed to oscillate freely. If the mass has a starting velocity of 2V, what would the period be? Half as long, remains constant, 1/4 as long , 4 times as long, or 2 times as long?
Answer:
Equation for SHM can be written
V = w A cos w t where w is the angular frequency and the velocity is a maximum at t = 0
V1 = w1 A cos w1 t
V2 = w2 A cos w2 t
V2 / V1 = w2 / w1 since cos X t = 1 if t = zero
V2 / V1 = 2 pi f2 / (2 pi f1) = f2 / f1 = T1 / T2
If the velocity is twice as large the period will be 1/2 long
what is the ratio of the average distances that oxygen will diffuse in a given time in air and water
A country is deciding what to do about pollution glven off by power plants.
Which of the following is an example of how science can be used to make
this decision?
O A. Scientists own most of the power plants in the United States.
O B. Scientists can measure how much pollution is given off
O C. Scientists know what kind of power plants people want.
OD. Scientists are allowed to pass laws about pollution
Answer:
option B is the correct answer
Explanation:
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A car of mass 5000 kg was initially moving at 100 km/h and stops at a distance of 55 m. Find the
magnitude of the net force (in N) acting to stop the car.
Answer:
|F| = 35 kN
Explanation:
a = F/m
100 km/hr(1000 m/km / 3600 s/hr) = 27.8 m/s
v² = u² + 2as
a = (v² - u²) / 2s
F/m = (v² - u²) / 2s
F = m(v² - u²) / 2s
F = 5000(0² - 27.8²) / 2(55)
F = - 35,072.9517...
a An object is tarown up with a velocity v = 6.02 +7.0j. Calculate the (1) time taken reach the maximum height (ii) the horizontal range (s = 10m/s2).
Answer:
(i) 0.6s (ii) 8.42m
Explanation:
U² = 6.02² + 7²
U = 9.23
angle of projection
tanø = 6.02/7
ø = 40.7
Time of fligt
t = Usinø/g
t = 9.23 sin 40.7/10
t = 0.6
H range = U²sin2ø/g
H = 9.23²sin 81.4/10
H = 8.42m
The time taken reach the maximum height is 0.6s and the horizontal range is 8.42m.
What is Velocity?Velocity is defined as the directional motion of an object which is indicated by the rate of change of position as observed from a particular frame of reference. It is measured by a particular standard of time. It is a vector quantity as it has both magnitude and direction.
It can be expressed as:
v= d/t
Where. v is the velocity in m/s
d is the displacement measured in meter 'm'
t is the time measured in seconds 's'
For above given information,
v = 6.02 +7.0j, so the initial velocity will be u
u² = 6.02² + 7²
u = 9.23m/s
Angle of projection, tanø = 6.02/7
ø = 40.7
Time taken= t = u sinø/g
t = 9.23 sin 40.7/10
t = 0.6s
Horizontal range = u²sin2ø/g
H = 9.23²sin 81.4/10
H = 8.42m
Thus, the time taken reach the maximum height is 0.6s and the horizontal range is 8.42m.
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Over half the global population faces a shortage of clean water. Which example is a point source water pollutant? pesticide run-off from farmers’ fields a sewer pipe draining directly into a river road oil washing into sewer drains, and eventually reaching waterways erosion from a denuded slope after a heavy rainfall
An example of a point source water pollutant is a sewer pipe draining directly into a river.
According to the United States Environmental Protection Agency, a point source pollution is defined as; “any single identifiable source of pollution from which pollutants are discharged, such as a pipe, ditch, ship or factory smokestack.”
Hence, an example of a point source water pollutant is a sewer pipe draining directly into a river. The pollution is coming from an easily identifiable source which is a sewer pipe connected to a river directly.
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5) You pull a 10.0 kg wagon along a flat road. You exert a force of 80.0 N at an angle of 30.0 degrees above the horizontal while you move the wagon 10.0 m forward. The coefficient of friction between the wagon and road is 0.500. Calculate the work down by you and the work done by friction.
Consult the attached free body diagram. The only forces doing work on the wagon are the frictional force opposing the wagon's motion and the horizontal component of the applied force.
By Newton's second law, the net vertical force is
• ∑ F [v] = n + (80.0 N) sin(30.0°) - mg = 0
where a is the acceleration of the wagon.
Solve for n (the magnitude of the normal force) :
n = (10.0 kg) g - (80.0 N) sin(30.0°) = 58.0 N
Then
f = 0.500 (58.0 N) = 29.0 N
Meanwhile, the horizontal component of the applied force has magnitude
(80.0 N) cos(30.0°) ≈ 69.3 N
Now calculate the work done by either force.
• friction: -(29.0 N) (10.0 m) = -290. J
• pull: (69.3 N) (10.0 m) = 693 J
A 500 kg cart is rolling to the right at 1.3 m/s. a 60 kg man is standing on the right end of the cart. what is the speed of the cart if tha man suddenly starts running to the left with a speed 10.0 m/s relative to the cart
Answer:
P1 = 1.3 (500 + 60) = 728 kg-m total momentum to right at start
P2 = (v2 - 10) 60 + 500 v2
total momentum after running at -10 with respect to cart = 728 where v2 is the new speed of the cart
728 = 560 v2 - 600
v2 = 1328 / 560 = 2.37 m/s new speed of cart
Check:
After: p2 for cart = 500 * 2.37 = 1186
p1 for man = (2.37 - 10) * 60 = -458
P2 = p1 + p2 = 728 total momentum unchanged
Students are asked to create roller coasters for marbles. Their goal is to design a coaster with the tallest possible hill that a marble released from a height of 1.5 m (meters) can clear. The marbles will experience some air resistance and friction as
they move.
What should the students keep in mind as they build their designs?
a)The hill can be taller than 1.5 m (meters), because the marble will be moving faster than its initial velocity allowing it to travel higher than its release height.
b)The hill can be taller than 1.5 m (meters), because the marble will gain mechanical energy as it moves allowing it to travel higher than its release height.
c)The hill should be a little less than 1.5 m (meters) high, because the marble will lose mechanical energy as it moves, preventing it from reaching its release
height.
d)The hill can be exactly 1.5 m (meters) high, because mechanical energy is always
conserved allowing the marble to travel to its release height.
Answer:
Kinetic Energy.
Explanation:
The movement of a roller coaster is accomplished by the conversion of potential energy to kinetic energy. The roller coaster cars gain potential energy as they are pulled to the top of the first hill. As the cars descend the potential energy is converted to kinetic energy.
Since the marble will loose mechanical energy, the hill should be a little less than 1.5 m (meters) high.
A roller coaster is used to demonstrate the conversion of mechanical energy. In a roller coaster, potential energy is converted to a kinetic energy hence it conveniently serves as a device for demonstrating energy conversions.
As the students make their design, they must bear in mind that the hill should be a little less than 1.5 m (meters) high, because the marble will lose mechanical energy as it moves, preventing it from reaching its release
height.
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can someone help me answer this question? A student connected an ammeter as shown in this picture. Did the student connect the ammeter correctly? Explain
Answer:
No - It is connected in parallel instead of series
Explanation:
The answer is No, the reason behind the answer that the ammeter is connected in parallel which is wrong it must be connected in series.
What is Ammeter?An ammeter is a device for detecting electric current in amperes, either directly (DC) or alternating (AC). Due to the fact that a shunt running parallel to the meter carries the majority of the electricity at high current values, the digital multimeter can measure a wide range of current values. A circle with the capital A in it serves as the icon for an ammeter for circuit diagrams.
The moving coil of the electrodynamics ammeter rotates in the field created by the fixed coil. It measures alternating and direct current with 0.1 to 0.25 percentage points (by converting Ac power To DC power using a rectifier).
The ammeter is connected in series and, on the other hand, the voltmeter is connected in parallel.
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Is acceleration included in a force diagram? Why?
Answer:
No
Explanation:
Acceleration is not a "Force"
The only things added on a force diagrams are forces that are acting on the object. Force causes acceleration to change but it is not a force itself and is not included on a force diagram.
Which would most likely form a homogenous mixture?
Answer:
B) a pinch of sugar mixed with cup of water
Answer:
A pinch of sugar mixed with a cup of water
Explanation:
A homogeneous mixtures have a uniform appearance where the parts are pretty evenly spaced out throughout the mixture. Picking out the individual pieces should be hard, ,which is why sugar in water is the best choice.
Croquet ball A moving at 8.3 m/s makes a head on collision with ball B of equal mass and initially at rest. Immediately after the collision ball B moves forward at 6.4 m/s .
What fraction of the initial kinetic energy is lost in the collision?
Answer:
0.25
Explanation:
That is the right answer.
The fraction of the initial kinetic energy is lost in the collision is 35.3%.
The given parameters:
Initial velocity of ball A = 8.3 m/sInitial velocity of ball B = 0Final velocity of ball B = 6.4 m/sThe initial kinetic energy of the system collision is calculated as follows;
[tex]K.E_i = \frac{1}{2} mv_1_i^2 + \frac{1}{2} mv_2_i^2\\\\K.E_i = \frac{1}{2} (m)(8.3)^2 + \frac{1}{2} (m) (0)^2\\\\K.E_i = 34.445 m[/tex]
The final velocity of ball A after collision is calculated as follows;
[tex]u_1 + v_1 = u_2 + v_2\\\\8.3 + v_1 = 0 + 6.4\\\\v_1 = 6.4 - 8.3\\\\v_1 = -1.9 \ m/s[/tex]
The final kinetic energy of the system after collision is calculated as follows;
[tex]K.E_f = \frac{1}{2} m(-1.9)^2 + \frac{1}{2} m(6.4)^2\\\\K.E_f = 22.285 \ m \[/tex]
The fraction of the initial kinetic energy is lost in the collision is calculated as follows;
[tex]= \frac{K_i - K_f}{K_i} \\\\= \frac{34.445 - 22.285}{34.445} \\\\= 0.353\\\\= 35.3\%[/tex]
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You throw an 8.75 g coin straight up into the air. The coin travels a distance of 337 cm upward. What was the initial speed of the coin when you released it
Answer:
hi
Explanation:
i like saying hi
At a distance of 1 cm from the source, the flux from the isotropic source is one hundred times brighter. Which source is brighter fifty centimeters away
Answer:
op
Explanation:
At a distance of 1 cm from the source, the flux from the isotropic source is one hundred times brighter. Which source is brighter fifty centimeters away
We have seen in earlier readings how to determine the speed of a wave on a string. What will happen to the wavelength of a sinusoidal wave on a string if the tension in the string is increased (assuming we keep the frequency of the wave the same)
This question involves the concepts of tension in a string and the wavelength of the wave in a string.
The wavelength of a sinusoidal wave will "increase by square power" on a string if the tension in the string is increased when the frequency is kept constant.
The speed of a wave on a string is given by the following formula:
[tex]v=\sqrt{\frac{T}{\mu}}[/tex]
where,
v = speed of wave = fλ
f = frequency of the wave
λ = wavelength of the wave
T = tension force
μ = linear mass density of the string
Therefore,
[tex]f\lambda=\sqrt{\frac{T}{\mu}}\\\\T = f^2\lambda^2\mu[/tex]
It is given that the frequency is kept constant. The linear mass density is also constant for a string. Therefore,
[tex]T=(constant)\lambda^2\\T\ \alpha\ \lambda^2[/tex]
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cuantos metros hay en 100cm?
Answer: 100cm = 1 meter.
Centi is 100, therefor meaning that 100cm is exactly 1 meter.
I hope this helps!
In the popular game "Angry Birds" (refer Figure), for the red bird to hit the green bird with their range 55.0 m, what should be the launch angle (with respect to the horizontal) of the slingshot if the time of flight is 2.50 s?
Answer:
Explanation:
What are we to use as gravity in this imaginary world? I will ASSUME 9.81 m/s² and assume no air resistance.
horizontal velocity component
vx = 55.0/2.50 = 22 m/s
vertical initial velocity component
(12.0 - 10.0) = 0 + vy₀(2.50) + ½(-9.81)2.50²
vy₀ = 13.0625 m/s
θ = arctan(vy₀/vx) = arctan(13.0625/22) = 30.6997225... = 30.7°
A 120 V fish-tank heater is rated at 130W. Calculate (a) the current through the heater when it is operating, and (b) its resistance
Explanation:
The power P dissipated by a heater is defined as
[tex]P = VI[/tex]
where V is the voltage and I is the current.
a) The current running through a 130-W heater is
[tex]I = \dfrac{P}{V} = \dfrac{130\:\text{W}}{120\:\text{V}} = 1.08\:\text{A}[/tex]
b) The resistance R of the heater is
[tex]P = VI = (IR)I = I^2R[/tex]
where [tex]V= IR[/tex] is our familiar Ohm's Law.
[tex]\Rightarrow R = \dfrac{P}{I^2} = \dfrac{130\:\text{W}}{(1.08\:\text{A})^2}[/tex]
[tex]R = 110.8\:Ω[/tex]
The current running through the heater when it is operating is 1.08 A.
The resistance of the heater is 110.8 ohm.
What is current?A current is a flow of Charges.The formula of current is , current I = power P / voltage VThe SI unit of current is ampere A.So, from the above equation we can calculate,
current I = P/V
∴ I = 130 / 120
∴ I = 1.08 A
What is resistance?The resistance is a quantity which oppose the current flow in a circuit.The formula of resistance is ( in the terms of power P and ohm's law V=IR ) resistance R = P/I^2.The SI unit of resistance is ohm.So, from the equation we can calculate,
Resistance R = P/I^2
∴ R = 130/(1.08)^2
∴ R = 110.8 ohm
Thus, the current running through the heater when it is operating is 1.08 A.
The resistance of the heater is 110.8 ohm.
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What are the three factors discussed in our live session that can lead to success through challenging physical activities:
Talent, flexibility, and stamina
Strength, balance, and endurance
Knowledge, attitude, and fitness level
Attitude, motivation, and determination
Answer:
Attitude, motivation and determination
Explanation:
Let me know if I'm right.
The factors leading to the success through the challenging physical activities are Attitude, motivation and determination.
Although the information regarding the live session is not mentioned, but as a general point of view, the major factors that need to considered while undergoing through the challenging physical activities are as follows:
Attitude - Attitude is one of the major factor leading to the management of challenges. A positive attitude always creates a base to face the initials of physical activities.Motivation - Motivation is another aspect that needs to be considered while undergoing the physical activities. Motivation comes from some sort of positive words from a specific person, thereby reducing the changes of poor start.Determination - The half battle is conquered with self-determination, a highly determined person is always has an add-on advantage for the task that he/she is going to start.Thus, we can conclude that the factors leading to the success through the challenging physical activities are Attitude, motivation and determination.
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In a thermodynamic process, the internal energy of a system in a container with adiabatic walls decreases by 800 J. Which statement is correct
The correct statement is, the system performed 800 J of work on its surroundings.
The given parameters:
change in internal energy, ΔU = 800 JApply first law of thermodynamics;
ΔU = Q + W
where;
Q is the heat gainedW is the work done on the system by the surroundingIn adiabatic process no heat is gained or lost by the system.
Q = 0
ΔU = W (work is positive when it is done on the system by its surrounding)
If work is done by the system to the surrounding, the new equation becomes;
ΔU = - W
W = - ΔU
W = -800 J
This implies that the system performed 800 J of work on its surroundings.
"Your question is not complete, it seems to be missing the following information";
In a thermodynamic process, the internal energy of a system in a container with adiabatic walls decreases by 800 J. Which statement is correct?
a. The system lost 800 J by heat transfer to its surroundings.
b. The system gained 800 J by heat transfer from its surroundings.
c. The system performed 800 J of work on its surroundings.
d. The surroundings performed 800 J of work on the system.
e. The 800 J of work done by the system was equal to the 800 J of heat transferred to the system from its surroundings.
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Describe all the ways a bicyclist can accelerate
i need help with these please
Answer:
Explanation:
In a model generator, a 310-turn rectangular coil 0.075 m by 0.18 m rotates with an angular frequency of 12.2 rad/s in a uniform magnetic field of 0.64 T. What is the maximum emf induced in the coil
This question involves the concepts of the induced emf, magnetic field, and angular frequency.
The maximum emf induced in the coil is "32.68 volts".
The following formula can be used to find out the induced emf in the coil.
[tex]E =N\omega AB\ Sin(\omega t)[/tex]
But, for maximum induced emf sin function should have a value of 1. Therefore,
[tex]E = N\omega AB[/tex]
where,
E = induced emf = ?
N = No. of turns in the coil = 310 turns
ω = angular frequency = 12.2 rad/s
A = Area of coil = (0.075 m)(0.18 m) = 0.0135 m²
B = magnetic field = 0.64 T
Therefore,
[tex]E=(310)(12.2\ rad/s)(0.0135\ m^2)(0.64\ T)[/tex]
E = 32.68 volts
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which of the following statements describes a perfectly inelastic collision
Answer: An ice hockey player picks up a trophy as he slides past it.
Two pool balls colliding precisely inelastically and rebounding off one another is an example. So, the correct option is A.
What is an Inelastic collision?Inelastic collisions are those in which the total kinetic energy is lower after the impact than it was before. The stick is travelling quickly in the direction of the ball before to the contact. The stick comes to a stop following the accident. It transfers some of its kinetic energy to the cue ball, which rolls forward.
The type of collision mentioned in the given example is known as an inelastic collision is one in which the system's momentum is preserved but its kinetic energy is not. In a ballistic pendulum, an example of an inelastic collision. Dropped ball of clay is another illustration of an inelastic collision.
Thus, the correct option is A.
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Your question is incomplete, most probably the complete question is:
Which of the following statements describes a perfectly inelastic collision?
A. Two billiard balls bounce off of each other,
B. A car crashes into a tree and rebounds in the other direction,
C. A wad of chewing gum is thrown and sticks to a moving truck,
D. Two ice skaters hit each other and fall over in opposite directions,
Which light is most sensitive to the eyes?
Answer:
Our eyes are most sensitive to the wavelengths corresponding to the yellow and green colors of the spectrum. Flashy signs and some fire engines are painted in a yellowish-green color to attract our attention.
An empty plastic or glass dish being removed from a microwave oven is cool to the touch. How can this be possible
Suppose the student in (Figure 1) is 68kg, and the board being stood on has a 12kg mass. What is the reading on the left scale? What is the reading on the right scale?
The equilibrium conditions allow to find the results for the balance forces are:
F₁ = 225.4 N F₂ = 558.6 N
When the acceleration is zero we have the equilibrium conditions for both linear and rotational motion.
∑ F = 0
∑ τ = 0
Where F are the forces and τ the torques.
The torque is the product of the force and the perpendicular distance to the point of support,
The free-body diagrams are diagrams of the forces without the details of the bodies, see attached for the free-body diagram of the system.
We write the translational equilibrium condition.
F₁ - W₁ - W₂ + F₂ = 0
We write the equation for the rotational motion, set our point of origin at scale 1, and the counterclockwise turns are positive.
F₂ 2 - W₁ 1 - W₂ 1.5 = 0[tex]\frac{W_1 \ 1 + W_2 \ 1.5}{2}[/tex]
Let's calculate F₂
F₂ = [tex]\frac{W_1 \ 1 + W_2 \ 1.5 }{2}[/tex]
F₂ = (m g + M g 1.5)/ 2
F₂ = [tex]\frac{(12 + 68 \ 1.5 ) \ 9.8}{2}[/tex]
F₂ = 558.6 N
We substitute in the translational equilibrium equation.
F₁ = W₁ + W₂ - F₂
F₁ = (m + M) g - F₂
F₁ = (12 +68) 9.8 - 558.6
F₁ = 225.4 N
In conclusion using the equilibrium conditions we can find the forces of the balance are:
F₁ = 225.4 N F2 = 558.6 N
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