A control group in a scientific experiment is a group separated from the rest of the experiment, where the independent variable being tested cannot influence the results. This isolates the independent variable 's effects on the experiment and can help rule out alternative explanations of the experimental results.
Answer:
members of a control group receive a standard treatment, a placebo, or no treatment at all.
Explanation:
Which of the following is a completely elastic collision?
A. a ball rebounds against a wall, reversing its direction, but at only half the speed.
B. Two balls collide, stick to each other, and move together after the collision.
C. Two balls collide and move at a right angle to each other after the collision at a reduced speed.
D. Two balls collide head on, each reversing its direction and traveling at half the speed.
E. A ball with velocity v collides with a ball at rest; after the collision the first ball is at rest and the second ball has velocity v.
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Hi there!
Answer E.
For a collision to be completely elastic, there must be NO LOSS in kinetic energy.
We can go through each answer choice:
A. Since the ball rebounds at half the initial speed, there is a loss in kinetic energy. This is NOT an elastic collision.
B. A collision involving sticking is an example of a perfectly INELASTIC collision. This is NOT an elastic collision.
C. A reduced speed indicates that there is a loss of kinetic energy. This is NOT elastic.
D. The balls traveling at half the speed after the collision indicates a loss of kinetic energy, making this collision NOT elastic.
E. This collision indicates an exchange of velocities, characteristic of an elastic collision. We can prove this:
Let:
m = mass of each ball
v = velocity
We have the initial kinetic energy as:
[tex]KE = \frac{1}{2}mv^2 + 0 = \frac{1}{2}mv^2[/tex]
And the final as:
[tex]KE = 0 + \frac{1}{2}mv^2 = \frac{1}{2}mv^2[/tex]
Thus, Kinetic energy is CONSERVED. This collision is ELASTIC.
Question 5. One 1,5V battery runs a portable MP3 player that draws 5,7mA of current
for about six hours before it runs out.
a) What is the resistance If the portable MP3 player?
b) How much power is dissipated in the portable MP3 player?
c) Find the energy delivered by the portable MP3 player?
A bullet of mass M1 is fired towards a block of mass m2 initially at rest at the edge of a frictionless table of height h as in the figure. The initial speed of the bullet is vi . Consider two cases, a completely inelastic one and an elastic one,where the bullet bounces off the block. inelastic case elastic case a bullet inside no bullet inside A B A' B' What is the ratio of the flight time; i.e., tAB tA′B′ ?
The ratio of time of flight for inelastic collision to elastic collision is 1:2
The given parameters;
mass of the bullet, = m₁mass of the block, = m₂initial velocity of the bullet, = u₁initial velocity of the block, = u₂Considering inelastic collision, the final velocity of the system is calculated as;
[tex]m_1u_1 + m_2u_2 = v(m_1 + m_2)\\\\m_1u_1 + 0 = v(m_1 + m_2)\\\\v= \frac{m_1u_1}{m_1 + m_2} \ -- (1)\\\\[/tex]
The time of motion of the system form top of the table is calculated as;
[tex]v = u + gt\\\\v = 0 + gt\\\\v = gt\\\\t= \frac{v}{g} \\\\t_A = \frac{m_1u_1}{g(m_1 + m_2)} \ \ ---(2)[/tex]
Considering elastic collision, the final velocity of the system is calculated as;
[tex]m_1u_1 + m_2 u_2 = m_1v_1 + m_2v_2\\\\m_1u_1 + 0 = m_1v_1 + m_2v_2\\\\m_1 u_1 = m_1v_1 + m_2v_2[/tex]
Apply one-directional velocity
[tex]u_1 + (-v_1) = u_2 + v_2\\\\u_1 -v_1 = 0 + v_2\\\\v_1 = v_2 -u_1[/tex]
Substitute the value of [tex]v_1[/tex] into the above equation;
[tex]m_1u_1 = m_1(v_2 - u_1) + m_2 v_2\\\\m_1u_1 = m_1v_2 -m_1u_1 + m_2v_2\\\\2m_1u_1 = m_1v_2 + m_2v_2\\\\2m_1u_1= v_2(m_1 + m_2)\\\\v_2 = \frac{2m_1u_1}{m_1+ m_2} \ --(3)[/tex]
where;
[tex]v_2[/tex] is the final velocity of the block after collision
Since the bullet bounces off, we assume that only the block fell to the ground from the table.
The time of motion of the block is calculated as follows;
[tex]v_2 = v_0 + gt\\\\v_2 = 0 + gt\\\\t = \frac{v_2}{g} \\\\t_B = \frac{v_2}{g} \\\\ t_B = \frac{2m_1u_1}{g(m_1 + m_2)} \ \ ---(4)[/tex]
The ratio of time of flight for inelastic collision to elastic collision is calculated as follows;
[tex]\frac{t_A}{t_B} = \frac{m_1u_1}{g(m_1 + m_2)} \times \frac{g(m_1 + m_2)}{2m_1u_1} \\\\\frac{t_A}{t_B} = \frac{1}{2} \\\\t_A:t_B = 1: 2[/tex]
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what is momentum?
what is period of an oscillating body?
what is friction?
Answer:
Explanation:
Momentum is the quantity of motion of a moving body, measured as a product of its mass and velocity.
The period of an oscillating body is the smallest interval of time in which a system undergoing oscillation returns to the state it was in at a time arbitrarily chosen as the beginning of the oscillation.
Friction is a force between two surfaces that are sliding, or trying to slide, across each other. Friction always slows a moving object down. The amount of friction depends on the materials from which the two surfaces are made. The rougher the surface, the more friction is produced.
alcohol thermometer cannot measure the thermometer of boiling water ,why?
Explanation:
The contents of alcohol are less toxic and will evaporate quickly as compared to the mercury-in-glass thermometer. Since, alcohol starts boiling at 80℃ while the boiling point of mercury is 375℃. ... So, an alcohol thermometer cannot measure the temperature of boiling water as it has the limit to measures up to 80℃.
A wave traveling at 230 m/sec has a wavelength of 2.1 meters. What is the frequency of this wave?
Answer:
109.52 HzExplanation:
The frequency of the wave when given it's velocity and wavelength only can be found by using the formula
[tex]f = \frac{c}{ \lambda} \\ [/tex]
where
c is the velocity of the wave in m/s
[tex] \lambda[/tex] is the wavelength in meters
From the question we have
c = 230 m/s
[tex] \lambda[/tex] = 2.1 m
[tex]f = \frac{230}{2.1} = 109.523809... \\ [/tex]
We have the final answer as
109.52 HzHope this helps you
describe the components of soil
Soil is a material composed of five ingredients — minerals, soil organic matter, living organisms, gas, and water. Soil minerals are divided into three size classes — clay, silt, and sand (Figure 1); the percentages of particles in these size classes is called soil texture.Soil contains air, water, and minerals as well as plant and animal matter, both living and dead. These soil components fall into two categories. ... Other, less common minerals include calcium, magnesium, and sulfur. The biotic and abiotic factors in the soil are what make up the soil's composition.
A crane does 9,500 J of work to lift a crate straight up using a force of 125 N. How high does the crane lift the crate? 0. 013 m 76 m 9,400 m 1,200,000 m.
The distance covered as the crane does work is 76 m.
Recall that the work done in lifting the crane is the product of force and distance covered. In this case, we are talking about the distance through which the crane is raised. Therefore;
Work done = Fs
F = Force applied
s = Distance covered
Substituting values;
Work done/Force applied = Distance covered
Distance covered = 9,500 J/125 N
Distance covered = 76 m
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A blue line with 5 orange tick marks then one red tick mark then 4 orange tick marks. The number zero is above the red tick mark. Assume each tick mark represents 1 cm. Calculate the total displacement if a toy car starts at 0, moves 5 cm to the left, then 8 cm to the right, and then 3 cm to the left. The car moves cm, so there is no displacement.
The total displacement of the toy car at the given positions is 0.
The given parameters;
First displacement of the car, = 5 cm leftSecond displacement of the car, = 8 cm rightThird displacement of the car, = 3 cm to the leftThe total displacement of the car is calculated as follows;
Let the left direction be "negative direction"Let the right direction be "positive direction"[tex]\Delta x = - \ 5\ cm \ + \ 8 \ cm \ - \ 3 \ cm \\\\\Delta x = 0[/tex]
Thus, the total displacement of the toy car at the given positions is 0.
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Answer:0
Explanation:
Mass can be measured with a triple
beam balance in units of
Resources
A. grams
B. Newtons
C. cubic centimeters
D. millimeters
Answer:
It can be measure by grams
What is the work done in lifting 60 kg of blocks to a height of 20m
Answer:
The answer is 1200
Explanation:
GUYS COULD SOMEONE PLEASE HELP ME?
PLEASE ASAP
Write a summary of how the eye works:
Answer:
Eye function renders you the sense of sight. They convert light into electrical signals. Afterwards, the brain deciphers these electrical signals into images. Properly working healthy eyes are able to perform the following functions.
Explanation:
A loaded truck collides with a car causing huge damage to the car. Which of the following is true about the collision? *
A. The force on the truck is greater than the force on the car
B. The force on the car is greater than the force on the truck
C. The force on the truck is the same in magnitude as the force on the car
D. During the collision the truck makes greater displacement than the car
E. During the collision the truck has greater acceleration than the car
The force on the truck is the same in magnitude as the force on the car.
The impulse experienced by an object during collision is directly proportional to the applied force and time of collision of the objects.
J = Ft
where;
J is the impulse experienced by the objectt is the timeThe increase in the force applied to an object causes an increase in the impulse experienced by the object.
Also, according to Newton's third law of motion, the force exerted on the loaded truck and the car are equal in magnitude but opposite in direction.
Thus, we can conclude that, the force on the truck is the same in magnitude as the force on the car.
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What should you do before inserting a wire into an outlet box?
A. Place a bushing inline.
B. Remove a foot of the outer covering.
C. Clean the terminals.
D. Strip at least three inches and re-twist the strands to retighten.
The first thing that you should do before inserting a wire into an outlet box is to remove a foot of the outer covering.
What is an outlet box?The outlet box is sometimes called the junction box. It is from this point that power is distributed to appliances in the home. Its main function is to protect against short circuits.
The first thing that you should do before inserting a wire into an outlet box is to remove a foot of the outer covering.
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I keep people warm I come in many different colors, styles, and materials. many people use me when they sit on a couch
Answer:
a seat
Explanation:
The phrase “seat value” is used in the hospitality and bar sectors to describe how much money each seat or square foot of customer area must generate to justify its existence.
What is the use of seat by the people?An area to sit is a seat. The phrase may also refer to headquarters in a more general meaning as well as extra elements such a back, armrest, and head restraint.
Being in the centre allows you to benefit from both the advantages of both front and back seating while balancing out their extremes. While you're still close enough to be paying careful attention to the lecture, the middle rows will relieve you of the pressure and expectations of the front.
By remaining seated, students help avoid physical altercations. There is more time spent on task when pupils are seated.
Environmental psychology, which gives people the impression that they have some degree of influence over their daily lives, is the driving force behind all of this behavior.
Therefore, seat used by people.
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A 66 kg student stands on a very light, rigid board that rests on a bathroom scale at each end as shown in (Figure 1).
The reading on the scale is equal to the weight of the student which is 646.8 N.
The given parameters;
mass of the student, m = 66 kgThe reading on the scale is determined by applying Newton's second law of motion as follows;
[tex]R = ma+ mg\\\\R = m(a + g)\\\\R = m(0 + g)\\\\R = mg[/tex]
The student is at rest and not accelerating, a =0
[tex]R = 66 \times 9.8\\\\R = 646.8 \ N[/tex]
Thus, the reading on the scale is equal to the weight of the student which is 646.8 N.
The complete question is below:
A 66 kg student stands on a very light, rigid board that rests on a bathroom scale at each end as shown in (Figure 1). what is the reading on the scale?
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An 50 kg student runs and jumps onto a 25 kg tire swing, which is initially at rest, and rides the swing up into the air. The swing (and the student) then rises a vertical distance of 1.5 m. What was the initial speed, in m/s of the swing? Remember the acceleration due to gravity near Earth's surface, g = 9.81 m/s^2
A. 29 m/s
B. 5.4 m/s
C. 1.7 m/s
D. 15. m/s
E. 3.8 m/s
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Answer:
Option B, 5.4m/s
Explanation:
Using the formula v² = u ² - 2gh
v = 0(final velocity is zero at maximum height), u = ?, g = 9.81m/s², h = 1.5m
0² = u² - 2×9.81×1.5
0 = u² - 29.43
29.43 = u²
u = √29.43
= 5.42m/s
A 50.0 kg crate is pulled 375 N of force applied to a rope. The crate slides without friction.
After being pulled 3.07 meters the crate has a velocity of 5.61 m/s. What is the angle (degrees) made by the rope with the horizontal?
Hi there!
We can use the work-energy theorem to solve.
Recall that:
[tex]\large\boxed{W = \Delta KE = \frac{1}{2}mv_f^2 - \frac{1}{2}mv_i^2}[/tex]
The initial kinetic energy is 0 J because the crate begins from rest, so we can plug in the given values for mass and final velocity:
[tex]W = \frac{1}{2}(50)(5.61^2) = 786.8025 J[/tex]
Now, we can define work:
[tex]\large\boxed{W = Fdcos\theta}}[/tex]
Now, plug in the values:
[tex]786.8025 = Fdcos\theta\\\\786.8025 = (375)(3.07)cos\theta[/tex]
Solve for theta:
[tex]cos\theta = .6834\\\theta = cos^{-1}(.6834) = \boxed{46.887^o}[/tex]
Initial Velocity is 27.5 m/s. Time is 42 seconds. Final Velocity is 4.5 m/s. Solve for acceleration.
Answer:
-0.5476
Explanation:
a=(Vf-Vi)/t
a=(4.5-27.5)/42
a=-0.547619047
acceleration≈-0.5476
Two 3.0g bullets are fired with speeds of 40.0 m/s
and 80.0 m/s, respectively. What are their kinetic
energies? Which bullet has more kinetic energy? What is the ratio of their kinetic energies?
[tex] = \sf \frac{1}{2} m {v}^{2} [/tex]
Kinetic energy of the 1st bullet [tex] \sf = \frac{1}{2} \times m1 \times {(v1)}^{2} \\ \sf= \frac{1}{2} \times 0.003 \times {(40)}^{2}J \\ \sf = \frac{1}{2} \times 0.003 \times 1600J \\ \sf = 2.4J[/tex]Kinetic energy of the 2nd bullet [tex] \sf = \frac{1}{2} \times m2 \times {(v2)}^{2} \\ \sf= \frac{1}{2} \times 0.003 \times {(80)}^{2}J \\ \sf = \frac{1}{2} \times 0.003 \times 6400J \\ \sf = 9.6J[/tex] So, the 2nd bullet which has greater velocity has more kinetic energy.Therefore, the ratio of their kinetic energies[tex] \sf = \frac{2.4J}{9.6J} \\ \sf= \frac{24}{96} = \frac{1}{4} \\ \sf = 1 : 4[/tex]
Answer:
The kinetic energies of the bullets are 2.4 J and 9.6 J.
The bullet having greater velocity has more kinetic energy.
The ratio of their kinetic energies is 1 : 4.
Hope you could get an idea from here
Doubt clarification - use comment section.
The kinetic energy of the two bullets are 2.4 J and 9.6 J respectively.
The ratio of the kinetic energy of the bullets is 1:4.
What is kinetic energy?The kinetic energy of an object is the energy possessed by the object due to its motion.
The kinetic energy of the two bullets is calculated as follows;
[tex]K.E_1 = \frac{1}{2} \times 0.003 \times 40^2 = 2.4 \ J\\\\K.E_2 = \frac{1}{2} \times 0.003 \times 80^2 = 9.6 \ J[/tex]
Ratio of the kinetic energy of the bullets is calculated as follows;
[tex]K.E_1 : K.E_2 = 2.4: 9.6 \ = \ 1: 4[/tex]
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Which particles within the atom are electricity charged?
a. Electrons only.
b. Neutrons only.
c. Protons only.
d. Electrons and protons.
e. Protons and neurons.
Answer:
I think b sorry if wrong
Explanation:
it b sorry if wrong
Answer:
Given that these particles make up atoms, they are often referred to as subatomic particles. There are three subatomic particles: protons, neutrons and electrons. Two of the subatomic particles have electrical charges: protons have a positive charge while electrons have a negative charge:
Jeremiah rides his bicycle 4 miles in 30 minutes. If he maintains this rate, how far will he ride in 3 hours?
Answer:
24 miles.
Explanation:
3 hours=180 minutes
180÷30=6
6x4=24
A car traveling at 100 km/hr strikes and unfortunate bug and splatters it.the net force of impact is
Answer:
it's zero
Explanation:
it is there is your answer
Is the image formed by a plane mirror always real?
True or false?
what are the ending materials produced from cell respiration
Answer:
The products of cellular respiration are carbon dioxide and water
Explanation:
Where in an equation for photosynthesis does glucose belong? on the left, because it is a product on the left, because it is a reactant on the right, because it is a product on the right, because it is a reactant
Answer: The answer is on the right, because it is a product.
Explanation: During photosynthesis, light energy converts carbon dioxide and water (the reactants) into glucose and oxygen (the products).
Glucose belongs to the right side in photosynthesis equation because it is a product on the right.
What is Photosynthesis?Photosynthesis is the conversion of light energy into chemical energy by green plants and other organisms. Light energy is collected and utilized by green plants during photosynthesis to transform water, carbon dioxide, and minerals into oxygen and energy-rich organic molecules Glucose.photosynthesis equation can be written as6CO2 + 6H2O → C6H12O6 + 6O2.
Carbon dioxide + Water → Glucose + oxygen
Hence, the correct option is C.
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When the mass of the cylinder increased by a factor of 3, from 1. 0 kg to 3. 0 kg, what happened to the cylindera's gravitational potential energy? It decreased by a factor of 3. It decreased by a factor of 2. It increased by a factor of 2. It increased by a factor of 3.
The mass of the cylinder increased by a factor of 3, the gravitational potential energy increases by a factor of 3.
The given parameters:
Initial mass of the cylinder, m₁ = 1.0 kgFinal mass of the cylinder, m₂ = 3.0 kgThe gravitational potential energy of an object is calculated as follows;
P.E = mgh
where;
m is the mass
g is acceleration due to gravity
h is the height of the cylinder
when the mass = 1 kg
P.E = 1 x g x h
P.E = gh
when the mass = 3 kg
P.E = 3 x gh
P.E = 3gh
Thus, when the mass of the cylinder increased by a factor of 3, the gravitational potential energy increases by a factor of 3.
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How long will it take a projectile to hit the ground if it is launched at 4.2 m/s off a 12.6 m high platform?
Answer: 3
Explanation:
I think you are supposed to divided in those problems? I'm not sure but if you aren't then please let me know. The equation I did was:
12.6 / 4.2 = 3
Hope this helps!! :)
What do scientists theorize about the origins of the Moon? Choose the most accepted explanation.
Answer:
What is most widely accepted today is a the giant-impact theory. It proposes that the Moon formed during a collision between the Earth and another small planet, about the size of Mars. The debris from this impact collected in an orbit around Earth to form the Moon.
A vertical spring stretches 9.6 cm when a 1.3 kg block is hung from its end. (a) Calculate the spring constant. This block is then displaced an additional 5.0 cm downward and released from rest. Find the (b) period, (c) freque
Answer:
F = - K x
a) K = 1.3 kg * 9.8 m/s^2 / .096 m = 133 kg/sec^2
b) ω = (K/m)^1/2 angular frequency of SHM
ω = (133 / 1.3)^1/2 = 10.1 / sec
f = 2 π ω = 6.28 * 10.1 / sec = 63.5 / sec
P = 1/f = .0157 sec