As Jack pulls his wagon down the street it moves faster and faster. Jill, sitting a few meters ahead on the sidewalk, wants to slow Jack's wagon down so that it travels with a constant speed. How can Jill accomplish her goal? A) Push the wagon with a force greater than Jack. B) Push Jack away from the wagon so that he is no longer pulling it. C) Pull on the wagon in the opposite direction with twice Jack's force. D) Push the wagon in the opposite direction at a constant force less than Jack.
Answer:
The correct answer is NONE the two forces must be equal and of opposite direction, the closest answer is D
Explanation:
In this exercise it is indicated that Jack pushes a car, it is desired that Jill pushes the car so that the speed is constant
take as positive the direction of Jack's thrust
F_jack - F_jill = 0
F_jill = F_jack
therefore the push of the two must be equal and Jill's push must have the opposite direction to Jack's push.
The correct answer is NONE the two forces must be equal and of opposite direction, the closest answer is D
Q. Calculate the annual energy
consumption, in kW-h, of
a hair dryer that is rated
at 1400 W and is used for
7.0 min every day.
(The answer in the textbook is 60 kW•h)
Answer:
60 kWh
Explanation:
The computation of the annual energy consumption in KW-h is shown below:
As we know that
1 kw = 1000 w
So, for 1400 W it would be
= 1,400 ÷ 1,000
= 1.4 kW
Now the number of hours it used in a year
= 7 minutes × 365 days ÷ 60 minutes
= 42.58333 hours
So in one year it used
= 1.4 kW × 42.58333
= 59.61 kWh
= 60 kWh
What chemical formula did early instigators assume for water?
Answer:
Explanation:
Investigators thought this meant that oxygen was eight times more massive than hydrogen. They presumed the chem-ical form-ula for water to be H-O
Hope this helped!!! .
What is the best way for the power plant manager to modify the reactor to meet the demand for electricity? lower the control rods, which will absorb more neutrons before they can split atoms raise the control rods so that fewer neutrons are absorbed and more can split uranium atoms remove some of the fuel rods, which will leave more room for additional neutrons to split atoms add additional fuel rods to generate additional neutrons to split uranium atoms
The question is incomplete, the complete question is;
During a heat wave, there is an increased demand for electricity to operate air conditioners. The basic design of a nuclear reactor that generates electricity is shown below. What is the best way for the power plant manager to modify the reactor to meet the demand for electricity?
a)lower the control rods, which will absorb more neutrons before they can split atoms
b)raise the control rods so that fewer neutrons are absorbed and more can split uranium atoms
c)remove some of the fuel rods, which will leave more room for additional neutrons to split atoms
d)add additional fuel rods to generate additional neutrons to split uranium atoms
Answer:
b)raise the control rods so that fewer neutrons are absorbed and more can split uranium atoms
Explanation:
A nuclear reactor uses a nuclear fuel to generate electricity. The nuclear reactor makes use of a fissile isotope such as Uranium-235 as nuclear fuel which is bombarded by neutrons and causes a nuclear fission to occur leading to a consequent initiation of a chain reaction.
Control rods are used to absorb some of the neutrons and keep the reaction under control.
When there is need to increase power generation, the control rods are raised so that less neutrons are absorbed by them and more of the uranium fuel is split.
A bucket is held up by a rope.
What force is pulling the bucket down?
O Force Gravity
O Force Tension
O Force Elastic
O Force Normal
Answer:
gravity...................
Answer:
Force GravityHope it help you
Which of the following regions of the EM epxtrum has the highest
frequency?
1) x rays
2) microwaves
3) infrared light
4) ultraviolet light
Answer:
1) x rays
Explanation:
Honestly Gamma rays has the Highest frequency, but in your options, gamma rays is not among, so x rays has the highest frequency among your options.
by Manshow
Answer:
The answer is (X-rays)
number 1
Explain why sounds are fainter at high mountains than sea level
can someone help ???
Answer:
All of these
Explanation:
HELP! What are 5 changes that a fidget spinner can be?
Answer:
I would hope they can change this question
Four different living organisms are shown on the right. Which statement is true for all of the organisms shown?
Answer:
they are all made of cells
GIVING BRAINLIEST PLEASE HELP!!
-if you answer correctly ill give you brainliest which will give you 20pts-
Answer:
c and d
because of the guy who is moving object in it say the worker
Explanation:
During the mature stage of a thunderstorm, air moves
upwards
downwards
towards sea
towards land
Answer: Downwards
Explanation: Upwards is only at the start of a thunderstorm when air moves towards the poles. During the mature stage, air moves down towards the equator.
a particle is projected from a point a with a velocity of 21m/s at an angle of 53.1 degees to the horizontal. one second later another particle is projected at a point 0.3m below a with initial velocity of 31.5m/s at an angle of 36.9 degrees to the horizontal.
(i) prove that the particles collide
(ii) find the time of collision
(iii) find the distance of collision from point of projection
Answer:
(i) Please see graph of the motion of the particles created with MS Excel and the calculations in the following sections
(ii) The time of collision is approximately 1.0 seconds
(iii) The common horizontal distance of point collision from the point of projection is approximately 25.2 meters
Explanation:
The velocity with which the first projectile was fired, v₁ = 21 m/s
The angle to the horizontal the particle is launched = 53.1°
The time at which the other particle was launched = 1 second later
The location from which the other particle was projected = 0.3 m below the first particle
The initial velocity of the second particle = 31.5 m/s
The angle to the horizontal at which the second particle was projected, θ = 36.9°
(i) The height reached, by each of the particle is given as follows;
y = u·t - 1/2·g·t²
For the first projectile, we have;
y = 21·(t₁+1)×sin(53.1°) - 9.81·(t₁+1)²/2 + 0.3
For the second projectile, we have;
y= 31.5·(t₁)×sin(36.9°) - 4.905·(t₁)²
If the two projectiles collide, we get;
21·(t₁+1)×sin(53.1°) - 9.81·(t₁+1)²/2 + 0.3 = 31.5·(t₁)×sin(36.9°) - 4.905·(t₁)²
Using a graphing calculator for simplifying, we get;
-11.93·t₁ + 12.2 = 0
t₁ = 12.2/11.93 ≈ 1.02
Therefore, at time t₁ = 1.02 seconds, after the launch of the second particle, the two particle will be at the same vertical height
However, whereby at the time, t₂, the particles collide, the horizontal distance travelled, 'x', will be equal;
We have;
x = u·cos(θ)·t₁
For the first particle, we have;
x₁₁ = 21 × cos (53.1°) × (t₂ + 1)
For the second particle, we have;
x₂₂ = 31.5 × cos (36.9°) × t₂
At the point of collision, we have;
x₁ = x₂
∴ 21 × cos (53.1°) × (t₂ + 1) = 31.5 × cos (36.9°) × t₂
31.5 × cos (36.9°) × t₂ - 21 × cos (53.1°) × t₂ = 21 × cos (53.1°)
t₂ = 21 × cos (53.1°)/(31.5 × cos (36.9°) - 21 × cos (53.1°) ) = 1.00219236871
t₂ ≈ 1.0 seconds
Given that t₁ ≈ t₂, the particles reach the same height and the same horizontal distance at the same time, t₂ ≈ 1.0 and therefore, they collide.
(ii) The time of collision is found above as t₁ ≈ t₂ ≈ 1.0 seconds
(iii) The horizontal distance of the point of collision from the starting point, 'x', is given as follows;
x = 21 × cos (53.1°) × (1.0 + 1) ≈ 25.2
The horizontal distance of the point of collision from the starting point, x ≈ 25.2 meters
The vertical distance of the point of collision from the starting point of the second particle, 'y', is given as follows;
y = 21 × (1+1)×sin(53.1°) - 9.81 × (1+1)²/2 + 0.3 ≈ 14
The vertical distance of the point of collision from the starting point of the second particle, y ≈ 14 meters
The magnitude of the distance from the starting point of the second particle, r = √(25.2² + 14²) ≈ 28.8
The magnitude of the distance from the starting point of the second particle, r ≈ 28.4 meters.
name three elements that have similar chemical properties to oxygen. (dont send me a link please)
It takes 5000 J of work to lift a crate to a height of 5 m in 10 s of time.. Calculate the power.
Answer:
P = 500 W
Explanation:
Given that,
Work done to lift a crate to a height of 5 m is 5000 J
It takes 10 s
We need to find the power of the crate. We know that power is the rate of doing work. Mathematically, it can be given by :
[tex]P=\dfrac{W}{t}\\\\P=\dfrac{5000}{10}\\\\P=500\ W[/tex]
So, the power of the crate is equal to 500 W.
Which describes the greenhouse effect? 1. Earth continues to get warmer over time because it is slowly moving closer to the sun. 2. Earth's atmosphere blocks the sun's ultraviolet light. 3. Pollution gets into the air, causing trees to not get enough oxygen. 4. Energy given off by earth is reflected off of earth's atmosphere back down to the surface.
Answer: The green house effect is best described by option 4 (Energy given off by earth is reflected off of earth's atmosphere back down to the surface).
Explanation:
The green house effect can be described as the energy given off by earth is reflected off of earth's atmosphere back down to the surface.
When energy from the sun passes through the atmosphere, some are absorbed which keeps the earth surface warm. While the rest is reflected back largely by cloud.
The energy which is emitted from the earth surface is called the infrared radiation. Some of the infrared radiation passess through the atmosphere but most is absorbed and re- emitted in all directions by the greenhouse gas molecules and clouds. This effect warms the earth surface and the lower atmosphere. Therefore this statement (Energy given off by earth is reflected off of earth's atmosphere back down to the surface) is correct about greenhouse effect.
For the greenhouse effect to occur, greenhouse gas molecules are mostly needed. Examples of these gases include:
--> Carbon dioxide (CO2),
--> Water vapor (H2O), and
--> Methane (CH4)
Over the years, the excessive human activities has lead to increase in the greenhouse gas molecules which has negatively affected the greenhouse effects.
How do positive and negative acceleration differ?
Positive acceleration represents an object speeding up; negative acceleration represents an object slowing down.
Positive acceleration moves north or east; negative acceleration moves south or west.
Positive acceleration occurs when there is more velocity than speed; negative acceleration occurs when there is less velocity than speed.
Positive acceleration occurs when an object changes its speed but not its direction; negative acceleration occurs when an object changes both its speed and direction.
Answer:
acceleration
Explanation:
acceleration determines whether you will be adding to or subtracting from the velocity. while negative acceleration means you will subtract from the current value of the velocity and a positive acceleration means you will add
1.
You just earned a $1000 bonus at your job. Would you rather receive all the money at the end of the
year or half the money now and half the money later? Why?
You have two photos of a person walking. One shows the person at the corner of Third and Main streets, the other shows the person at the corner of Tenth and Main streets. There are lampposts at every corner in this town, and the first picture shows it to be 10:32:00 exactly. The second picture shows it to be 10:49:30. You know three facts: (1) All of the clocks are synchronized; (2) there are exactly 12 equal-sized blocks per kilometer in this town; and (3) the streets that cross Main in this area are numbered consecutively, with no interruptions. What is the person’s average speed in kilometers per hour?
Answer:
average speed
= [(10-3)/12 km] / [(49.5-32.0)/60 hour]
= 5*7 / 17.5
= 2 km/h .
Running water has materials such as dirt, sand, and dead plants and animals in it. When this water ends up in a lake, the materials it was carrying fall to the bottom of the lake and form layers. A layer is thicker when more water enters the lake. For example, thick layers form during times of heavy rain, and thin layers form during times of little rain. Sometimes lakes dry up. The bottoms of dry lakes can change into rock. This rock will still have layers. A geologist studied one of these rocks made from the bottom of a lake. Which rock layer formed during the wettest season? Layer
Answer:
The outside layer is the wettest.
Explanation:
the body acts on a force of 3N with the shoulder 20 cm. What is her moment?
Answer:
0.6Nm
Explanation
Given
Force = 3N
Distance = 20cm = 0.2m
Moment = Force * perpendicular distance
Substitute
Moment = 3N * 0.2
Moment = 0.6Nm
Hence her moment is 0.6Nm
What is the main function (job) of the immune system?
A. to produce hormones for growth and development
B. to protect you from illness and disease
C. to get rid of waste in the body
Answer:
B. to protect you from illness and disease
Explanation:
The immune system protects your body from outside invaders, such as bacteria, viruses, fungi, and toxins . It is made up of different organs, cells, and proteins that work together.
Hope this helped!!
What two types of tactical communication vary based on whether or not you speak?
Answer:
If you don't have autism/deaf/anything like that you should be able to speak
Explanation:
Answer:
Verbal and nonverbal
Explanation:
Took the test
How is it possible a plant can sustain itself for 70 years locked inside a jar?
Answer:
If you are talking about the experiment in which mouse and plants are kept in a closed glass jar in sunlight so in that case, they both survive because the CO2 released by the respiration of mouse is being utilized by the plants and fixed ( phosynthesis) and O2 is released as by product, which is taken by the mouse for respiration.
Explanation:
Un engrane que gira con una velocidad de 20 rad/s, es acelerado durante 5 segundos hasta alcanzar una velocidad de 35 rad/s
a) ¿Cuál es la magnitud de su aceleración angular?
b) ¿Cuántos radianes gira en ese tiempo?
c) ¿Cuántas revoluciones alcanza a girar en ese tiempo?
no m ignoren
Answer:
a) La aceleración angular es: [tex]\alpha=2\: rad/s^{2}[/tex]
b) El engranaje gira 125 radianes.
c) El engranaje hara aproximadamente 20 revoluciones.
Explanation:
a)
La aceleración angular se define como:
[tex]\alpha=\frac{\Delta \omega}{\Delta t}[/tex]
Donde:
Δω es la diferencia de velocidad angular (en otras palabras ω(final)-ω(inicial))Δt es el tiempo en el que occure el cambio de velocidad angular[tex]\alpha=\frac{35-25}{5}[/tex]
[tex]\alpha=2\: rad/s^{2}[/tex]
b)
El desplazamiento angular puede ser calculado usando la siguiente ecuación:
[tex]\theta=\theta_{i}+\omega_{i}t+\frac{1}{2}\alpha t^{2}[/tex]
Aqui el angulo inicial es 0, por lo tanto.
[tex]\theta=20(5)+\frac{1}{2}(2)(5)^{2}[/tex]
[tex]\theta=125\: rad[/tex]
El engranaje gira 125 radianes.
c)
Lo que debemos hacer aquí es convertir radianes a revoluciones.
Recordemos que 2π rad = 1 rev
Entonces:
[tex]\theta=125\: rad \times \frac{1\: rev}{2\pi\: rad}=19.89\: rev[/tex]
Por lo tanto el engranaje hara aproximadamente 20 revoluciones.
Espero te haya sido de ayuda!
HELP MEEEEE
(science)
Answer:
Decreases the friction between the mallet and the pick.
Why are fats and waxes solid at room temperature?
Answer:
Fats and waxes are solid at room temperature because they are made of saturated fatty acids. In contrast, oils are mostly unsaturated fatty acids. ... In contrast, unsaturated fatty acids have several kinks in their structure and therefore, are liquid at room temperature.
If a ball is lifted 2 meters off the ground and 5 Newtons of force were needed to move it,
what amount of work has been done? :3
Answer:
W = 98 J
Explanation:
Given hat,
Force, F = 5 N
It is lifted 2 m off the ground.
We need to find the amount of work done. We know that, the work done by an object is given by the product of force and displacement. So,
W = Fd
or
W = mgd
Put all the values,
W = 5 × 9.8 × 2
W = 98 J
So, the work done is equal to 98 J.
If an object is sitting motionless on table, the normal force is...
A. Not present
B. the same forest as the force of the table pushing up on the object of interest
C. an extra force in addition to the force that the table applies to the object
Answer:
B. the same forest as the force of the table pushing up on the object of interest
How you work out efficiency?
Answer:
The work efficiency formula is efficiency = output / input, and you can multiply the result by 100 to get work efficiency as a percentage. This is used across different methods of measuring energy and work, whether it's energy production or machine efficiency.
Explanation:
Hope this helped!!!