For the chi-square (x^2) test to be valid, N must be large enough so that for every cell the expected cell count will be equal to 5 or more.
To make the x^2 test valid, N must be large enough so that for every cell the expected cell count will be equal to 5 or more. In other words, N must be such that each cell in the contingency table has a sufficient number of observations to ensure that the test is reliable. Some guidelines suggest that N should be at least 10 or more, while others suggest that N should be at least 5 or more. However, the most important consideration is to ensure that the expected cell count is not too low, as this can lead to inaccurate or misleading results. Therefore, the key condition for a valid x^2 test is to have a sufficiently large sample size to ensure that each cell has an expected count of at least 5.
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How much heat is required to raise the temperature of 2.0 kg of concrete from 10C to 30C? (The specific heat of concrete is 880 j/kg-C.)
A. 22 J
B. 88 J
C. 8800 J
D. 35200 J
Answer:B
Explanation:
Identify the following as
Potential Energy or Kinetic Energy
1. A car in the driveway. Potential energy
2. Matt rolling down a hill. Kinetic energy
3. Katie and Leo kissing.
4. A battery on my desk.
5. The water just before it goes down a waterfall.
6. A lawnmower running.
7. Mrs. Rey yelling at you.
8.A toy
9.A table with a spread of food
10. The kids playing on the bus.
PLEASEEE HURRY!!
Can you tell me How the sun is responsible for all of the energy here on Earth?
Answer:
Explanation:
All of the energy from the Sun that reaches the Earth arrives as solar radiation, part of a large collection of energy called the electromagnetic radiation spectrum. Solar radiation includes visible light, ultraviolet light, infrared, radio waves, X-rays, and gamma rays.
Car manufacturers use radiation for which task? sealing windows drying paint cleaning tires lubricating engines
Answer: drying paint
Explanation:
From the options that are given in the question, we should note that car manufacturers use radiation for drying paint.
The radiation is vital as it keeps the car cool and also helps in the reduction if heat in the vehicle. The other options such as sealing windows, cleaning tires and lubricating engines aren't true as radiation isn't used for that purpose by the car manufacturers.
Answer:
drying paint
Explanation:
Let the displacement function of a particle is x(t)=(20t^2-15t+200). Find the total displacement, instantaneous velocity and instantaneous acceleration
Answer:
A.) 39.5 m
B.) 0
C.) 60m/s^2
Explanation:
Given that a displacement function of a particle is x(t)=(20t^2-15t+200).
To Find the total displacement,
Reduce everything by dividing them by 5
X(t) = 4t^2 - 3t + 40 ...... (1)
For instantaneous velocity, differentiate x(t). That is,
dy/dt = 60t - 15 ...... (2)
But dy/dt = velocity.
If dy/dt = 0, then
60t - 15 = 0
60t = 15
t = 15/60
t = 0.25s
Substitutes t in equation (1)
Total displacement will be
X(t) = 4(0.25)^2 - 3(0.25) + 40
X(t) = 0.25 - 0.75 + 40
Total displacement = 39.5 m
To calculate instantaneous velocity, substitute t into equation (2)
V = 60 (0.25) - 15
V = 0.
and to find instantaneous acceleration, differentiate dv/dt
dv/dt = 60
Therefore, acceleration = 60 m/s^2
If the total force acts in the opposite direction as the cabinet is sliding, the cabinet would
A) slow down
B) speed up
C) remains the same speed
D) slow down, change direction and then speed up going the other way
E) remains the same speed, but changes direction
Please help!!!!!!:>>>>>>
Answer: 6V
Explanation: parallel circuit, the voltage is the same for each resistor.
Based from the flow chart, what can you generalize about the formation of typhoons? How do typhoons develop?
Answer: Warm water from the ocean is needed to develop typhoon
Pls Rate this as Brilliant Answer thank you :) keep on learning
Typhoons form when strong winds blow into warm areas of the ocean. These winds pick up moisture and rise, bringing colder air with them. This creates pressure, causing the winds to move quickly. The winds revolve or spin around a central point known as an eye.
What is typhoon ?A typhoon is a mature tropical cyclone that forms in the Northern Hemisphere between 180° and 100°E. The Northwestern Pacific Basin is the most active tropical cyclone basin on Earth, accounting for nearly one-third of the world's annual tropical cyclones.
The Philippines is just above the equator and faces the western Pacific, with little else to absorb storm energy before it reaches land. Storms are fueled by warm, tropical waters, which produce approximately 20 typhoons per year.
Hurricanes and typhoons can wreak havoc on coastlines and hundreds of miles inland. They can generate winds of up to 155 mph, as well as tornadoes and microbursts.
Thus, Typhoons form when strong winds blow into warm areas of the ocean.
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ANSWER THE ALL THE QUESTIONS IN THE FOLLOWING FOR 90 POINTS!
25
89
105
99
I don't know. I'm sorry
An object’s momentum includes its __________.
Answer: Momentum can be defined as "mass in motion
Explanation:
Someone Help me please
Answer:
a) Yes because spiderman isn’t part of the system (the train), so he exerts an external force on the system, causing it to slow. The sign is negative because the train is slowing negative.
b) The train was initially moving, so it had kinetic energy, the energy of movement. There isn’t the same amount anymore because spiderman did work onto the train. Work is defined by the change of kinetic energy of the system, so the train didn’t have the same amount of that type of energy at the end.
I hope this helps! :)
plzz answer fast, plzz help mee
Will mark as brainliest !! plz answer it
Plzzz answer with explnation!!!
the value of acceleration due to gravity (g) will be maximum at:
.
a) 1/2 of the radius of earth
b) 1/4 of the radius of earth
c) 1/8 of the radius of earth
READ ALL PLEASE
So I have been giving away points
But now that i have a lot I shall do another points give away yes
Now hurry and add a answer :V
Answer:
can I have please I will follow u..............
ANSWER QUCIK
PLS THANK YOU
i’m like kinda bad at physics so ya please help
Answer:
99 joules.
Explanation:
Let m denotes mass of the object and v denotes velocity.
If mass has units of kilograms and the velocity has units of meters per second then the kinetic energy has units of joules.
Kinetic energy is an energy possessed by a body in motion.
Mass (m) = 99 kg
Velocity (v) = 2 m/s
To find kinetic energy, use the following formula:
Kinetic energy = [tex]\frac{1}{2}mv^2=\frac{1}{2}(99)(2)=99[/tex] joules
A 2.0kg pendulum swings from point A of a height of 0.10m to a point B of the same height. The heights are relative to the lowerst height. What is the change in gravitational potential energy from A to B?
A 2.0 kg pendulum swings from point A of height yA = 0.10 m to point B of the same height. The heights are relative to the lowest height.
What is the change in gravitational potential energy from A to B?
Answer: 0 J
a load of 600 kg is lifted by a carne up to 60 meters in 6 minutes . calculate it work and power.
Explanation:
work=force*distance. force=load/10
___________
work=60*60=3600n
power=work/time(seconds)
Powe required is 1000
Explanation:
-Given: M= 600kg H: 60
-Time of operation: t = 6 min = 360 seconds
-Work done in lifting boxes: w= mgh (600 x 10 x 60) = 360,000
-Power required: p=[tex]\frac{w}{t} = \frac{360000}{360} = 1000[/tex]
if a person is 6.25 m away from a 60.0 w speaker, what is the sound level they are hearing?
(treat the speaker as a point source.)
Answer:
111dB
Explanation:
First, find the intensity of the sound using the formula I = Power / 4 x pi x radius ^2
So
60.0 / (4 x 3.14 (6.25)^2)
= 0.122
Then plug that into the equation to find sound level, which is 10log( I / Io)
Io being (1 x 10^-12)
So
10log(0.122 / 1 x 10^-12)
= 111dB
Hope this helps :)
Which of the following Resistors A, B, C or D, would use the least power? Make
your claim, give evidence and explain your reasoning. You may use math to support
your claim.
Please Help.
i think the answer is D 10.0
A clock which has a brass pendulum beats second correctly when the temperature of
the room is 30°c. It gains the time 15.55 sec per day when the temperature of the
rooms falls to 10°C. Find the linear expansivity of brass.
Answer:
- 0.0481666 °C^-1
Explanation:
Linear expansivity of brass, α
α = (2T - 2T0) / T0.dt
T0 = 30°
dt = change in temperature = 30 - 10 = 20°C
T = 15.55 sec
α = (2*15.55 - 2*30) / 30*20
α = (31.1 - 60) / 600
α = - 28.9 / 600
α = - 0.0481666 °C^-1
What type of wave is this. I can figure it out
A spring with k = 33.5 N/m has a
1.20 kg mass attached. It is pulled
0.120 m and released. How much
mechanical energy does it have?
(Unit = J)
Answer:
M.E = 0.241 Joules.
Explanation:
Given the following data;
Spring constant, k = 33.5 N/m
Extension, e = 0.12m
Mass = 1.20kg
To find the mechanical energy (M.E);
Mathematically, mechanical energy is given by this formula;
M.E = ½ke²
Where;
k is the constant of elasticity (spring constant). e is the extension of the string.Substituting into the equation, we have;
M.E = ½*33.5*0.12²
M.E = ½*33.5*0.0144
M.E = 0.4824/2
M.E = 0.241 Joules.
A 12 kg object speeds up from an initial velocity of 10 m/s north to a final velocity of 15 m/s north. Calculate the change in momentum
Answer:
60m/s
Explanation:
momentum = Mass × Velocity
Initial Momentum = 12 × 10
= 120
Final Momentum = 12×15
=180
Change in Momentum = 180 - 120
= 60m/s
Answer:
60Explanation:
formula for change in momentum = F =∆p/∆t
F∆t = ∆p
∆p = m(v - Vo)
∆p = 12(15-10)
=12(5)= 60
pls help i’ll give brainliest if you give a correct answer!!
Answer: The gravitational force acting on the table.
Explanation:
Unlike Electromagnetic waves, Mechanical waves need a to
transfer energy
You have two lens A and B of focal length +50cm and -50cm respectively. The nature and power of the lenses respectively isa. Concave, -2 D ; Convex, +2 D b. Convex, +2 D; Concave, - 2 D
Answer:
Concave, +2D
Convex -2D
Explanation:
Power of a lens is the reciprocal of its focal length.
For lens of +50cm = 0.5m
Power of the lens = 1/0.5
Power of the lens = +2Dioptres
Since the focal length is positive, the lens is concave
For the lens of -50cm = -0.5m
Power = 1/-0.5
Power = -2D dioptres
Since the focal length is negative, the lens is convex
John is hiking and notices a small stream of water flowing down the side of the mountain. What part of the water cycle is John observing?
Question 3 options:
Runoff
Evaporation
Condensation
Precipitation
Answer:
A runoff
Explanation: A runoff is when frozen water melts so if it falls down a mouantan there probably melting ice hope this helps :} pls give brainlest
John is hiking and notices a small stream of water flowing down the side of the mountain. In this John is experiencing runoff of the water cycle. Thus, the correct option is A.
What is Runoff?Surface runoff is the flow of water which is occurring on the ground surface when there is excess rainwater, storm water, melt water, or other sources of water, which can no longer sufficiently rapidly infiltrate in the soil of the region.
Runoff occurs in the excessive rainwater and it saturates the ground surface. Rivers and lakes are the results of water runoff. There is some evaporation from the water runoff into the atmosphere however for the most part water in the rivers and lakes returns back to the oceans.
Therefore, the correct option is A.
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An 850 kg elevator is accelerating upwards at 3.0 m/s2. Calculate the tension in the cable.
Answer:
10880N
Explanation:
We are given that
Mass of elevator, m=850 kg
Acceleration, [tex]a=3m/s^2[/tex]
[tex]g=9.8m/s^2[/tex]
We have to find the tension in the cable.
We know that
When elevator is accelerating upward then tension in the cable
[tex]T=m(a+g)[/tex]
Using the formula
[tex]T=850(3+9.8)[/tex]
[tex]T=10880N[/tex]
A 0.15 kg. baseball flies rightward at 15m/s to hit a tennis ball flying at it from
the opposite direction of 22 m/s. The baseball and the tennis ball have a
final speed of 1.2 m/s and 13 m/s respectively, both to the right.
What is the mass of the tennis ball?
(w/solution)