Answer:
98%
Explanation:
Given parameters
Mass of motor = 10kg
Height = 2m
Time = 2s
Power input = 100w
Unknown
Efficiency = ?
Solution
Efficiency is the percentage of the power output to the power input.
Power is the rate at which work is done.
Power output = mass x g x height / time
g is the acceleration due to gravity
Power output = 10x 2 x 9.8 / 2 = 98W
Efficiency = power output/ power input x 100
Efficiency = 98/100 x 100 = 98%
How do I solve this problem please help
Answer:
som,eythiung did cant wait
Explanation:
ya so i texted maria and she said i con c()me over so letyeyey yeah betty letty
PAINN I MISS JUOICE WORLDD PAINNNN
A 2 kg toy car moves at a speed of 5 m/s. If a child applies a 5N force for 2 m in the same direction the car is already moving, what is the change in kinetic energy of the car?
Answer:
[tex]10\: \mathrm{J}[/tex]
Explanation:
The kinetic energy of an object is [tex]KE=\frac{1}{2}mv^2[/tex], where [tex]m[/tex] is the mass of the object and [tex]v[/tex] is the velocity of the object.
The toy car's initial kinetic energy is [tex]KE_{i}=\frac{1}{2}\cdot 2\cdot 5^2=25\: \mathrm{J}[/tex].
After the child applies a 5N force on it in the same direction, its velocity will increase but its mass will stay the same.
To find the final velocity of the toy car, we can use kinematic equation [tex]v_f^2=v_i^2+2a\Delta x, \\ v_f=\sqrt{v_i^2+2a\Delta x}[/tex]
We are given [tex]v_i=5\: \mathrm{m/s}[/tex] and [tex]\Delta x = 2\: \mathrm{m}[/tex].
To find acceleration:
[tex]F=ma, a=\frac{F}{m}=\frac{5}{2}=2.5\: \mathrm{m/s^2}[/tex].
Now substitute [tex]v_i=5\: \mathrm{m/s}, \: a=2\: \mathrm{m/s^2}, \: \Delta x = 2\: \mathrm{m}[/tex] into [tex]v_f=\sqrt{v_i^2+2a\Delta x}[/tex] to get [tex]v_f\approx 5.92\: \mathrm{m/s}[/tex].
Using this, we can find the final kinetic energy of the toy car is [tex]KE_f=\frac{1}{2}\cdot 2\cdot 5.92^2[/tex].
Thus, the change in kinetic energy is [tex]KE_f-KE_i=\frac{1}{2}\cdot2\cdot 5.92^2-\frac{1}{2}\cdot 2\cdot 5^2=\fbox{$10\: \mathrm{J}$}[/tex] (one significant figure).
The change in the kinetic energy of the car is 10 J.
The given parameters;
mass of the car, m = 2 kginitial velocity of the car, u = 5 m/sforce applied by the child, F = 5 Ndistance traveled, s = 2 mThe acceleration of the car is calculated as follows;
[tex]F = ma\\\\a = \frac{F}{m} \\\\a = \frac{5}{2} \\\\a = 2.5 \ m/s^2[/tex]
The final velocity of the car is calculated as follows;
[tex]v^2 = u^2 + 2as\\\\v = \sqrt{u^2 + 2as} \\\\v = \sqrt{5^2 \ + \ 2(2.5)(2)} \\\\v = 5.92 \ m/s[/tex]
The change in the kinetic energy of the car is calculated as follows;
[tex]\Delta K.E = \frac{1}{2} m(v^2 - u^2)\\\\\Delta K.E = \frac{1}{2} \times 2 \times (5.92^2\ - \ 5^2)\\\\\Delta K.E = 10 \ J[/tex]
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a spring stretches from an initial height of 5 cm to a final stretch of 10 cm. the spring constant is 800 n/m.How much work was done on the spring?
what is the final force on the spring when it is at its 10 cm stretch?
explain why it is not appropriate to use the equation w=f//d when considering springs.
Answer:
.
Explanation:
F = kx so k = 800/((10-5)/100) = 16000 N/m
W = 1/2 kx^2 = 1/2 * 16000 * .05^2 = 20 J.
(sorry if it's wrong)
The speed limit on some segments of interstate 4 is 70 mph. What is this in km/h?
Answer:
112.63km/hr
Explanation:
The given dimension is :
70mph
We are to convert this to km/hr
1 mile = 1.609km
so;
70mph x 1.609 = 112.63km/hr
So,
The solution is 112.63km/hr
Many scientific studies have found that colds are caused by viruses. What is this? *
Fact
Interpretation
Analysis
Opinion
Answer:
Analysis
Explanation:
Because you must Analysis each and every cold too find out which virus caused this.
It’s weird because Interpretation and Analysis have the meaning of examination
Two 0.60-kilogram objects are connected by a thread that passes over a light, frictionless pulley. The objects are initially held at rest. If a third object with a mass of 0.30 kilogram is added on top of one of the 0.60-kilogram objects and the objects are released, the magnitude of the acceleration of the 0.30-kilogram object is most nearly:______
Answer:
2 m/s²
Explanation:
From the given information:
The first mass m_1 = 0.6 kg
The second mass m_2 = 0.3 kg
The magnitude for the acceleration of 0.3 kg is:
a = net force/ effective mass
Mathematically, it can be computed as follows:
[tex]a = \dfrac{F}{m}[/tex]
[tex]a = \dfrac{(m_2 +m_1 -m_1) }{(m_2+m_1+m_1)}(g)[/tex]
[tex]a = \dfrac{0.3 +0.6 -0.6}{(0.3 +0.6+0.6)}(9.8)[/tex]
a ≅ 2 m/s²
A tangent line drawn on a velocity-time graph has a rise of 19 m/s and a run of 4.0 m/s. How large is the acceleration? What type of acceleration Is this?
Answer:
Acceleration = 4.8 m/s²
Explanation:
Given:
Change in velocity = 19 m/s
Change in time = 4 s
Find:
Acceleration
Computation:
Acceleration = Change in velocity / Change in time
Acceleration = 19/4
Acceleration = 4.8 m/s²
Positive acceleration
A ball rolling on the floor eventually comes to a stop. Which statement best describes this situation?
A) The energy on the macroscopic scale and the energy on the molecular scale both decreased.
B) The energy on the macroscopic scale increased, and the energy on the molecular scale decreased.
C) The energy on the macroscopic scale decreased, and the energy on the molecular scale increased.
D) The energy on the macroscopic scale and the energy on the molecular scale both remained constant.
If you have the rest please put them down :)
Answer:
Explanation:
C. The energy on the macroscopic scale decreased, and the energy on the molecular scale increased.
A. friction converts some energy on the macroscopic scale to energy on the molecular scale.
B. The mechanical energy of the system decreased because of friction.
B. The mechanical energy of the system at the beginning of the experiment is equal to the mechanical energy of the system at the end of the experiment.
B. the mechanical energy of the system decreased due to the transfer of energy on a macroscopic scale to energy on a molecular scale.
The ball rolling on the floor eventually comes to a stop which means that
the energy on the macroscopic scale decreased, and the energy on the
molecular scale increased.
What is Macroscopic scale?This is a scale in which an object can be seen with the eyes. When
an object is in motion, the ball rolls away and becomes less visible hence a
decrease in the macroscopic scale.
During motion, friction converts some macroscopic energy into molecular
scale which is why there was an increase in it.
Read more about Macroscopic scale here https://brainly.com/question/17609067
The second law of thermodynamics imposes what limit on the efficiency of a heat engine?
A. The energy a heat engine must deposit in a cold reservoir is greater than or equal to the energy it extracts from a hot reservoir.
B. The energy a heat engine must deposit in a cold reservoir is greater than or equal to the energy extracted as useful work.
C. A heat engine must deposit some energy in a cold reservoir.
Answer:
C. A heat engine must deposit some energy in a cold reservoir.
Explanation:
The second law of thermodynamics says that "It is impossible to extract an amount of heat Q from a hot reservoir and use it all to do work W. Some amount of heat q must be exhausted to a cold reservoir."
This means that if we extract an amount of heat Q from the hot reservoir, the work W can never be exactly equal to Q, then there is a surplus of heat q that must be deposited in a cold reservoir.
Then we have the equation:
Q = W + q
From this we can conclude that the correct option is:
C. A heat engine must deposit some energy in a cold reservoir.
There will be always some energy that is not transformed into work, and is deposited in a cold reservoir.
C. A heat engine must deposit some energy in a cold reservoir.
The second law of thermodynamics says that "It is impossible to extract an amount of heat Q from a hot reservoir and use it all to do work W. Some amount of heat q must be exhausted to a cold reservoir". This means that if we extract an amount of heat Q from the hot reservoir, the work W can never be exactly equal to Q, then there is a surplus of heat q that must be deposited in a cold reservoir. Then we have the equation: Q = W + q There will be always some energy that is not transformed into work, and is deposited in a cold reservoir.Therefore, option C is correct.
Learn more:
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A bottle rocket is fired off and has an acceleration of 14.5 m/s2 for the 2.25s until it burns out. If it starts at rest, what distance does it cover?
Answer:
S = 16.3125m
Explanation:
Given the following data;
Acceleration, a = 14.5m/s²
Time, t = 2.25secs
Since the bottle rocket starts from rest, its initial velocity is 0m/s.
To find the distance S, we would use the second equation of motion.
S = ut + ½at²
Substituting into the equation, we have
S = 0(2.25) + ½*14.5*2.25
S = 0 + 7.25*2.25
S = 16.3125m
Therefore, the bottle rocket covered a distance of 16.3125 meters.
A 87 kg man has a total mechanical energy of 1780 J .If he is swinging downward and is currently 1.4 m above the ground, what is his speed? Use g = 10 m/s^2
Answer:
6.4m/s
Explanation:
The total mechanical energy of the man is 1780J.
This mechanical energy is the energy due to the motion of the body and it is a form of kinetic energy.
Also, mass = 87kg
Kinetic energy = [tex]\frac{1}{2}[/tex] m v²
m is the mass
v is the velocity
1780 = [tex]\frac{1}{2}[/tex] x 87 x v²
v² = 40.9
v = 6.4m/s
Static electricity is the build up of an electrical charge on the surface of an
object. Why is it called "static" electricity?*
Answer: Static electricity is the build up of an electrical charge on the surface of an object. It's called "static" because the charges remain in one area rather than moving or "flowing" to another area.
Explanation:
_____________________health is how you feel and how you react to situations bases on how you feel.
Group of answer choices
Mental
Physical
Emotional
Social
Answer: Emotional
Explanation:
Answer:
Physical
Explanation:
I love going going for a jog or a run so does my dog
In the diagram at the right, each grid square is 1.0μmx 1.0 μm. If Mass A = Mass C = 10kg and Mass B = 28 kg, determine the gravitational field at the location marked by the red dot.
Answer:
B
Explanation:
8-2 is 6
times that times 8 u get B
Which action will leave the dump trucks inertia unchanged?? PLEASE ANSWER FAST!!!
A. add gas
B. increase force applied to engine
Answer:
B.
Explanation:
explain resolution of Force
Answer:
it is defined as splitting up the given force into a number of components, without changing its effects on the body is called resolution of forces. A force is generally resolved along with two mutually perpendicular directions.
Explanation:
5.
What is the apparent colour of a red shirt when viewed in pure green light.?
Red
(b)- Green
Yellow (d) Black) (e) Blue
Answer: black
Explanation: When green light is shone on a red object, it absorbs all of the green light and not reflecting anything. Hence, it appears black.
A swift moving hawk is moving due west with a speed of 30 m/s; 5.0 s later it is moving due north with a speed of 20 m/s.
(A) What are the magnitude and direction of Δvav vector during this 5 s interval? and
(B) What are the magnitude and direction of vector aav during this 5 s interval?
Answer:
See explanation
Explanation:
Now we have;
vi = (-30, 0) m/s
vf = (0, 20) m/s
Δvav= vf - vi= (30, 20) m/s
magnitude of Δvav= √30^2 + 20^2 = 36.0 m/s
Direction = tan-1(20/30) = 33.69°
For aav
aav= Δvav/t = (30/5, 20/5) = (6,4) m/s^2
magnitude of aav = √6^2 + 4^2 = 7.2 m/s^2
direction of aav = tan-1(4/6) = 33.69°
Planet Earth is held in orbit by the sun's gravitational force pulling on the Earth.
Which one of the following statements are true about that gravitational force?
The sun does not have a gravitational force because it is made of gas.
The earth pulls with more force since it is less massive than the sun.
The sun and the earth pull on each other with equal and opposite forces.
The sun pulls with more force since the sun is more massive than the earth.
Answer:
The sun pulls with more force since the sun is more massive than the earth.
Explanation:
That your answer because the Earth is getting pulled by the gravitational pull from the Sun
PLEASEEEEEE HELPPPPPPP
Define resistance and discuss how it affects current.
Answer:
Resistance is the opposing of the flow of current through a conductor.
John and Tom were given one mirror each by their teacher. Tom found his image to be erect and of the same size whereas John found her image erect and smaller in size. This means that the mirrors of John and tom are, respectively
(a) plane mirror and concave mirror.
(b) concave mirror and convex mirror.
(c) plane mirror and convex mirror.
(d) convex mirror and plane mirror
Answer:
(d)
Explanation:
John- convex mirror
Tom - plane mirror
Answer:
(d) convex mirror and plane mirror
Explanation:
A plane mirror forms an image that is : virtual { behind the mirror } , image and object are at the same distance from the flat mirror, image is upright and image size is the same as object size. Tom's image.
A concave mirror form both real and virtual images. When a concave mirror is very near to an object , the image is virtual and magnified. When the distance between object and mirror is increased, a real image is formed and the size is reduced.
In a convex mirror, the image formed is smaller than the object, it is upright and is located behind the mirror. The image is virtual. John's image.
treatment for PTSD campus be described A.multumodal multi-phasic b. atheoretical C. stress inclusion D.eclectic
Answer:
Stress inclusion
Explanation:
A type of cognitive behavior therapy for PTSD is pressure inoculation preparation. CBT is a widely used form of antidepressant that can make you know wrong and/or pessimistic emotions that have influenced your actions and alter them.
Which has a greater momentum and greater kinetic energy-a truck with
a mass of 3530 kg moving at a speed of 21 m/s or a car with a mass of
1620 kg moving at a speed of 54 m/s? Answers below are given in the
form: greater momentum, greater kinetic energy.
Answer:
the car has greater momentum.
the car has greater kinetic energy.
Explanation:
FOR MOMENTUM:
Momentum is given as the product of mass and velocity of an object:
[tex]P = mv[/tex]
where,
P = momentum
m = mass
v = velocity
For Truck:
[tex]P_{truck} = (3530\ kg)(21\ m/s)\\P_{truck} = 74130 Ns[/tex]
For Car:
[tex]P_{car} = (1620\ kg)(54\ m/s)\\P_{car} = 87480\ Ns[/tex]
Therefore, car has greater momentum.
FOR KINETIC ENERGY:
Kinetic Energy is given as:
[tex]K.E = \frac{1}{2} mv^{2}[/tex]
where,
K.E = Kinetic Energy
m = mass
v = velocity
For Truck:
[tex]K.E_{truck} = \frac{1}{2} (3530\ kg)(21\ m/s)^{2}\\K.E_{truck} = 778365\ J = 778.36\ KJ[/tex]
For Car:
[tex]K.E_{truck} = \frac{1}{2} (1620\ kg)(54\ m/s)^{2}\\K.E_{truck} = 2361960\ J = 2361.96\ KJ[/tex]
Therefore, car has greater kinetic energy.
Why is damage from sound waves is an issue on the launchpad but not in the air
(I would have done more points for answering but I'm almost out sry. just pls answer and help.)
The sound wave does not damage the air because no external factors such as reflection, amplification, and vibrations are present. However, in the launch pad factors such as reflection, amplification, and vibrations are present which damages the sound wave.
Closeness to the Sound Source: When a rocket is fired on the launchpad, it creates a tremendous amount of noise in proximity to the nearby equipment and structures.
When a rocket is launched, concentrated sound waves are created that can seriously harm neighboring structures, especially if such structures are not built to handle such strong vibrations. In contrast, once a rocket is in the air, the sound waves spread out and become less forceful as they travel through the atmosphere, decreasing the possibility that they may cause harm.
Reflection and Amplification: The launchpad environment can serve as an echo chamber for sound waves because of its huge, solid structures.
Hence, The sound wave does not damage the air because no external factors such as reflection, amplification, and vibrations are present. However, in the launch pad factors such as reflection, amplification, and vibrations are present which damages the sound wave.
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A 65 kg box is lifted by a person pulling a rope a distance of 15 meters straight up at a constant speed. How much Power is required from the person in order to complete this task in 9 seconds?
__ Watts
Answer:
Power is 1061.67W
Explanation:
Power=force×distance/time
Power=65×9.8×15/9 assuming gravity=9.8m/s²
Power=3185/3=1061.67W
how does a battery work?
Answer:
Essentials. A battery is a device that stores chemical energy and converts it to electrical energy. The chemical reactions in a battery involve the flow of electrons from one material (electrode) to another, through an external circuit. The flow of electrons provides an electric current that can be used to do work.
Do it in order.
from smallest to largest
Answer:
The earth, The sun, the solar system and the milky way.
7Which of the following terms describes how glaciers move?
A Quickly
B Gradually
C Aggressively
D Rapidly
Answer:
D is the answer I think (0 w 0 )
Explanation:
The glaciers move gradually. Hence, option (C) is correct.
What is glacier?A glacier is a long-lasting mass of heavy ice that is perpetually moving. When the ablation of snow is greater than the accumulation over a long period of time, frequently centuries, a glacier forms.
As it slowly flows and deforms under forces brought on by its weight, it gains distinctive features like crevasses and seracs. Cirques, moraines, and fjords are the result of the erosion of rock and debris from its substrate as it travels.
The considerably thinner sea ice and lake ice that form on the surface of bodies of water are not the same as glaciers, which form only on land and may flow into water bodies.
The huge ice sheets, commonly referred to as "continental glaciers," in the polar areas of the planet contain 99 percent of the planet's glacial ice.
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how much power does it take to do 104 J of work in 8 sec?
Answer:
Given:
W=104J
t=8sec
Solve:
P=?
Equation:
P=W/t or Fd/t
P= 104J'8sec
P=13W
A rectangular reflecting pool is 85.0 ft wide and 120 ft long. What is the area of the pool in square meters?
