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:
An object is moving with a constant velocity of 311 m/s. How long will it take it to travel 9000 m?
[tex]\text{Given that,}\\\\\text{Velocity, v= 311 m s}^{-1}\\\\\text{Displacement, s = 9000 m}\\\\\text{Since velocity is constant,}\\\\s=vt\\\\\implies t =\dfrac{s}v = \dfrac{9000}{311} = 28.94 ~ \text{sec}.[/tex]
Find the heat energy is required to change 2Kg of ice at 0 C to water at 20 C ( specific latent heat of fusion of water = 336000 J/Kg and specific heat of capacity of water = 4200 J/Kg C
We want to find the energy that we need to transform 2kg of ice at 0°C to water at 20°C.
We will find that we must give 840,000 Joules.
First, we must change of phase from ice to water.
We use the specific latent heat of fusion to do this, this quantity tells us the amount of energy that we need to transform 1 kg of ice into water.
So we need 336,000 J of energy to transform 1kg of ice into water, and there are 2kg of ice, then we need twice that amount of energy:
2*336,000 J = 672,000 J
Now we have 2kg of water at 0°C, and we need to increase its temperature to 20°C.
Here we use the specific heat, it tell us the amount of energy that we need to increase the temperature per mass of water by 1°C.
We know that:
specific heat of capacity of water = 4200 J/kg°C
This means that we need to give 4,200 Joules of energy to increase the temperature by 1°C of 1kg of water.
Then to increase 1°C of 2kg of water we need twice that amount:
2*4,200 J = 8,400 J
And that is for 1°C, we need to give that amount 20 times (to increase 20°C) this is:
20*8,400 J = 168,000 J
Then the total amount of energy that we must give is:
E = 672,000 J + 168,000 J = 840,000 J
If you want to learn more, you can read:
https://brainly.com/question/12474790
a galaxy that is a featureless spherical ball of stars would be called a type
Answer:
E0
Explanation:
Yes. The "0" indicates that it is spherical
A 40W lamp wastes 34 J of energy every second by heating its surroundings.
What is the efficiency of the lamp?
С
18%
D
85%
A
0.15%
15%
B
Answer:
[tex]15\%[/tex].
Explanation:
The efficiency of a machine is the percentage of energy input that was turned into useful energy.
The power rating of this lamp is [tex]40\; \rm W[/tex] (same as [tex]40\; \rm J \cdot s^{-1}[/tex],) meaning that [tex]40\; \rm J[/tex] of energy is supplied to this lamp every second.
The question states that [tex]34\; \rm J[/tex] out of that [tex]40\; \rm J[/tex] of energy input would be turned into heat, which is not useful energy output in this scenario. Assuming that all other forms of energy loss is negligible. The rest of the [tex](40\; \rm J - 34\; \rm J) = 6\; \rm J[/tex] of energy supplied to this lamp would be turned into useful energy output.
Thus, every second, this lamp would receive [tex]40\; \rm J[/tex] of energy input and would outputs [tex]6\; \rm J[/tex] of useful work. The efficiency of this lamp would be:
[tex]\begin{aligned}& \text{Efficiency} \\ =\; & \frac{\text{Useful energy out}}{\text{Total energy in}} \times 100\% \\ =\; & \frac{6\; \rm J}{40\; \rm J} \times 100\%\\ =\; &15\% \end{aligned}[/tex].
Use what you know about mass and how you use it to calculate force in the following situation. If each washer has a mass of 4. 9 g, then the mass of two washers in kilograms would be. Given that F = ma, and if 4 washers are attached to the string and car instead of 2, then the applied force on the car will be. Recall a = 10 m/s2.
Considering the change of units and the definition of weight, the mass of two washers would be 0.0098 kg and if 4 washers are attached to the string, then the applied force on the car will be 0.196 N.
Mass of two washers
If each washer has a mass of 4.9 g, then the mass of two washers will be calculated simply by multiplying the mass of 1 washer by the amount you have of them, in this case 2:
4.9 g×2= 9.8 g
Being 1 kg = 1000 g, you apply the following rule of three to make the change of units: if 1000 g equals 1 kg, 9.8 g equals how many kilograms?
[tex]mass=\frac{9.8 gramsx1 kg}{1000g}[/tex]
Solving:
mass= 0.0098 kg
Finally, the mass of two washers would be 0.0098 kg.
Applied forceOn the other side, mass is the amount of matter that a body contains and weight is the action exerted by the force of gravity on the body.
The mass of an object will always be the same, no matter where it is located. Instead, the weight of the object will vary according to the force of gravity acting on it.
Weight is calculated as the product of the object's mass and the value of the gravitational acceleration:
W= m×g
In this case, you know:
m= 4.9 g×4= 19.6 g= 0.0196 kg → the mass of 4 washers in kilogramsg= 10 m/s²Replacing:
W= 0.0196 kg× 10 m/s²
Solving:
W= 0.196 N
Finally, if 4 washers are attached to the string, then the applied force on the car will be 0.196 N.
Learn more:
brainly.com/question/15566515?referrer=searchResults brainly.com/question/15271930?referrer=searchResults brainly.com/question/4735812?referrer=searchResultsAnswer:
C, B
Explanation:
A position versus time graph is shown:
Position vs. Time
1 15
10
10
Time (seconds) ->
Which statement accurately describes the motion of the object in the graph above?
O It is at rest for 3 seconds before moving at constant speed for 10 seconds.
It is at rest for 3 seconds before moving at constant speed for 4 seconds.
Olt is moving from 0 cm to 5 cm at constant speed of 7 cm/s.
O it is moving from 0 cm to 3 cm at a constant speed of 3 cm/s.
Answer: Answer: The object moves forward at 5 m/s, stops, and then changes velocity.
Explanation:
With the information given in the question we can graph the points (image attached).
As we can observe, in the first segment of the graph the velocity is increasing linearly (at a constant rate) and is 5 m/s, then in the second segment we can see the position of the object remains the same from second 2 to second 4, which means the object is stopped.
Finally, in the third and last segment, we can observe a change in velocity (at a negative constant rate, because is decreasing), which is decreasing until the object stops.
Explanation:
How to do this question plz
Answer:
C
Explanation:
Most discussions of refraction will have a diagram similar to that of C.
The angle of incidence is measured from the normal to the boundary, as is the angle of refraction. The product of the sine of the angle and the index of refraction is the same for the media on either side of the boundary.
n₁·sin(θ₁) = n₂·sin(θ₂)
For media, such as optical fiber, that has an index of refraction greater than 1, the angle of refraction will be smaller in that media than the angle of incidence coming from air.
Figure C applies.
A medieval instrument used to determine the position of the sun:
Answer: astrolabe
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:
how does the age of the universe depend on the hubble constant?
what is the definition for the term Resistance?
Answer:
Hey mate....
Explanation:
This is ur answer.....
There are 2 definitions :-
The refusal to accept or comply with something.The ability not to be affected by something, especially adversely.Hope it helps!
Brainliest pls!
Follow me! :)
What is the control group
Answer: the group in an experiment that doesn’t get treatment
Explanation:
Convert: 12 km/hr =
m/s
[tex]12~ \text{km} ~ \text{h}^{-1} = \dfrac{12 \times 1000}{3600} ~~ \text{m s}^{-1} = 3.33 ~~ \text{m s}^{-1}[/tex]
Answer:
3 1/3 or 3.3333....
Explanation:
You multiply the kilometres by 1,000 because there are 1,000 metres in a kilometre. Then you divide by 60 because there are 60 minutes per hour, and then again by 60 because 60 seconds per minute.
12,000 / 60 = 200
200 / 60 = 3.333
How far does an object travel if it is moving at a speed of 4 m/s for 3.2 seconds?
SOMEONE PLEASE HELP ME
Answer:
12.8 metres
Explanation:
distance = speed x time
distance = 4 x 3.2
distance = 12.8
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℃.
What is the frequency of a wave with a wavelength of 15 m and a wavespeed of
300 m/s?
Answer: f=20 (i think)
Explanation:
all I did was divide 300 and 15.
300/15= 20
A swimming pool of width 9.0 m and length 12.0 m is filled with water to a depth of 3.0 m. Calculate pressure on the bottom of the pool due to the water.
Hint: 1 m^3 of water has a mass of 1000 kg.
With the use of the formula, the pressure on the bottom of the pool due to the water is 29400 Pascal
Given that a swimming pool of width 9.0 m and length 12.0 m is filled with water to a depth of 3.0 m.
Volume = Length x Width x Height
Volume = 9 x 12 x 3
Volume = 324 [tex]m^{3}[/tex]
Since 1 m^3 of water has a mass of 1000 kg,
Mass = 324 x 1000
mass = 324000 kg
To calculate the pressure on the bottom of the pool due to the water, let us use the pressure formula below
P = δgh
where
P = pressure
δ = density of the water = 1000 kg/[tex]m^{3}[/tex]
g = Acceleration due to gravity = 9.8 m/[tex]s^{2}[/tex]
h = height = 3m
Substitute all the parameters into the formula
P = 1000 x 9.8 x 3
P = 29400 Pascal
Therefore, the pressure on the bottom of the pool due to the water is 29400 Pascal
Learn more about Pressure here: https://brainly.com/question/25736513
Which statement best explains why a wet saw used to cut through a fine optical crystals is constantly lubricated with oil
The major reason why a wet saw that is used in cutting optical crystals is constantly lubricated with oil is largely due to friction, lubrication decreases friction and minimises the increase of internal energy.
Friction is basically the coming together of two parts that rubs against each other, it causes heat and lead to deterioration of surfaces, it can also lead to wear and tear.
Although, despite it down side, friction is desire-able in most applications
e.g the brake system of vehicles, and if not for friction, we humans cannot walk without falling
learn more:
https://brainly.com/question/24338873
Make a super villain out of these resources
Answer:the super villain would have the ability to control electricity and could take any Metal object or weapons that anyone points at him because he is magnetic
Explanation:
what does it mean to be skeptical of health fraud
Something that is falsely advertised to help different health issues. An example could be Eyeball massagers
A multi-dimensional being reaches down to Earth and pulls you out of the universe. You are then thrown back into the universe at a place and time of the being's choosing, and you are permitted to leave only after you have identified your surroundings. This process is repeated several times. Through a scientifically unexplainable miracle, you are able to survive in every one of the places that you find yourself. In each scenario below, identify your surroundings (and potentially your cosmic era) from among the choices given. You find yourself in a place that is unimaginably hot and dense. A rapidly changing gravitational field randomly warps space and time. Gripped by these huge fluctuations, you notice that there is but a single, unified force governing the universe.
Required:
Where are you?
You are in an early universe.
In the study of the evolution of the universe, it has been determined before Plank time (before the big bang and right after it), the early universe had the following characteristics:
There was only one single force acting over all that existed.The early universe was very hot and dense because all matter had contracted before the big bang.Space and time were wrapped.These characteristics match the ones described, based on this, we can conclude you are in an early universe.
Learn more about universe in: https://brainly.com/question/9724831
PE:
Write T in the blank if the statement is true and E if it is false.
_____1. A basketball game starts with a jump ball.
_____2. Basketball is a cardiovascular work-out.
_____3. The middle of the basketball court is called the sideline.
_____4. Unlimited substitutions are allowed during a regular basketball game.
_____5. If the ball crosses the sideline, it is considered out of bounds and goes to the other team.
_____6. A turnover is any loss of the ball without a shot being taken.
_____7. A player may intentionally kick the ball for the team's benefit.
_____8. When dribbling a ball, a basketball you want to keep the ball below your waist and off to the side of your body.
_____9. If your opponent shoots at the wrong hoop your team receives the points.
_____10. After a player stops dribbling the ball in basketball, he or she is allowed 4 steps to pass or shoot.
Answer:
The answers are:
T, T, F, F, T, T, F, F, T, T, F
Good luck!
An object is struck by a 5N force for 8 seconds causing the object to experience a change in it's motion. What is the impulse acting on the object?
Hi there!
Recall the equation for impulse:
[tex]I = \Delta p = F * t[/tex]
Where:
I = Impulse (Ns)
F = Force (N)
t = Time (s)
Plug in the given values:
I = 5 · 8 = 40 Ns
Hi, please help! •_•
One workman is measured as having a power of 528W. His weight is 800N. He can develop the same power climbing a ladder, whose rungs are 30cm apart. How many rungs can he climb in 5s?
Answer:
He can climb 11 rungs
Explanation:
Power = 528W, Force = 800N, Time= 5s Total Distance moved = 30x cm or 0.3x m, where x is the number of rungs he climbed
Power = Work done/time
Work done = Power × time
= 528 × 5
= 2640Joules
Also Work done = Force × total distance moved
Total Distance moved = Work done/force
0.3x = 2640/800
0.3x = 33
x = 3.3/0.3
x = 11
I was walking with Ruby in a garden from rest in a straight line with uniform acceleration so that we covered 0.25 m in the fifth second of our motion. Calculate our acceleration.
Answer:
0.02m/s^2
Explanation:
An open train car rolls along a track while it is being filled with sand. There is negligible friction. As a result of
the accumulating sand, what happens to the speed of the train car? (Assume negligible friction and the cart is
just rolling along, not receiving any additional force to regulate its speed.)
Answer:
Explanation:
that`s a the train car, that you asked the meaning, of that if the train car rolls it`s doing it`s speed, and it`s not ganna fall off the the trail of the train, car.An open train car rolls along a track while it is being filled with sand. There is negligible friction. The speed of the train car will be slowed down.
What is friction?Between two surfaces that are sliding or attempting to slide over one another, there is a force called friction. For instance, friction makes it challenging to push a book down the floor.
Friction always moves an object in a direction that is counter to the direction that it is traveling or attempting to move.
Speed indicates the rate of movement of something or someone. If you know how far something has traveled and how long it took to get there, you can calculate its average speed. Speed is calculated as follows: speed = distance x time.
Therefore, an open railway car is packed with sand and is rolling along a track. Very little friction exists. The railway car's speed will be slowed down.
To learn more about friction, refer to the link:
https://brainly.com/question/13000653
#SPJ2
The deceleration of the dummy is less than the deceleration of the passenger compartment.
Explain why this is of benefit for the safety of a passenger.
Based on the information given, this is beneficial because the passenger is less likely to be injured.
Deceleration simply means acceleration in a reverse way. Deceleration simply means the rate at which an object slows down.
From the complete information, it should be noted that the fact that the deceleration of the dummy is less than the deceleration of the passenger compartment is beneficial as it impacts on passenger or dummy less than without the airbag or seat belt.
Therefore, this is important as the passenger is less likely to be injured.
Learn about deceleration on:
https://brainly.com/question/75351
rube goldberg machine steps
Answer:
Rube Goldberg Machine is "a comically involved, complicated invention, laboriously contrived to preform a simple operation." 2. What are the 6 Simple Machines? A. The 6 Simple Machines are: wedge, screw, lever, wheel and axel, inclined plane and pulley.
A 75 kg diver has 5,150.25 J of gravitational potential energy. Determine the diver’s height
Answer:3.4m
Explanation:
When traveling north from the United States into Canada, you'll see the North Star (Polaris) getting _________. lower in the sky higher in the sky dimmer brighter
When traveling north from the United States into Canada, you'll see the
North Star (Polaris) getting higher in the sky .
This is because the polaris which is also known as North Star is located
very close to the north celestial pole. When an objects moves towards the
north , the polaris gets higher due to its upward northern location.
This is the major reason why when traveling north from the United States
into Canada, you'll see the North Star (Polaris) getting higher.
Read more about Polaris on https://brainly.com/question/1130377
Answer:
Higher
Explanation:
As you go further north, the Star Polaris rises in the sky. This is due to it being circumpolar meaning that the star doesn't move in the night sky (Often)