The efficiency of the torch light from the total energy supplied and useful energy is 46.7%.
Efficiency of the torch
The efficiency of the torch is the amount of energy used to produce light compared to the total energy supplied to the torch light. This can also be called useful energy.
Total energy supplied to the torch = 150 J
Total energy used to produce light = 70 J
The efficiency of the torch light is calculated as follows;
Efficiency = 70/150 x 100%
Efficiency = 46.7%
Thus, the efficiency of the torch light from the total energy supplied and useful energy is 46.7%.
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From what height should you drop a ball so that it hits the ground at 40 m/s? How long will it take to hit the ground?
Explanation:
It is given that,
A ball hits the ground at 40 m/s
Let h is the height from where you drop a ball. It is based on the conservation of energy as :
[tex]mgh=\dfrac{1}{2}mv^2\\\\h=\dfrac{v^2}{2g}\\\\\text{Putting all the values in above formula}\\\\h=\dfrac{40^2}{2\times 9.8}\\\\h=81.63\ m[/tex]
It is dropped from a height of 81.63 m.
Let it take t seconds to hit the ground. When it hits the ground, its final speed, v = 0 and u = 40 m/s. So,
[tex]h=ut+\dfrac{1}{2}gt^2\\\\h=\dfrac{1}{2}gt^2\\\\t=(\dfrac{2h}{g})^{1/2}\\\\t=(\dfrac{2\times 81.63}{9.8})^{1/2}\\\\t=4.08\ s[/tex]
So, it will take 4.08 seconds to hit the ground.
1.When I cook an egg in a microwave oven, the device uses electromagnetic energy to increase the kinetic energy of particles of matter in the egg.
2.Many stoves and ovens have exhaust fans overhead to remove the rising warm air from the kitchen. The thermal energy is added to air and it rises.
3.When I cook an egg in a pan, thermal energy is transferred as the egg touches the hot surface of the pan. The thermal energy is transferred as objects touch.
choose which one are Conduction, Convection or Radiation
Answer:
1: Radiation 2: Convection 3: Conduction
Explanation:
Which does not utilize the gyroscope effect?
Question options:
a spiral pass in football
a spinning top
a flying plastic disk
a magnetic compass
A device that converts mechanical energy into electrical energy
A. electromagnet.
B. telephone.
Answer:
A
Explanation:
Hope this helps. Please if you need more information let me know
50 points.
Lab: Newton's Laws of Motion Section III: Analysis and Discussion What do the key results indicate? If you constructed graphs, what trends do they indicate in your data?
A 4kg ball that is moving straight upward has 20J of kinetic energy and its total mechanical energy is 32J. Find the gravitational potential energy of the ball
Answer:
h = 0.25 [m]v = 3.26 [m/s]
Explanation: In order to solve this problem, we must remember that mechanical energy is defined as the sum of kinetic energy plus potential energy.
The primary coil of a transformer has 800 turns and the secondary coil has 8 turns. It is connected to a 220 volt a.c. supply. What will be the output voltage??
Don't Spam ^_^
-_+
Given :-
Primary voltage = 220 voltNo. of turns secondary turns = 8No. of primary turms = 800[tex] \\ \\ [/tex]
To find :-
Secondary voltage.[tex] \\ \\ [/tex]
We know:-
[tex] \boxed{ \rm\dfrac{E_s}{E_p}=\dfrac{N_s}{N_p}}[/tex]
where :-
E_s = Secondary voltageE_p = primary voltageN_s = No. of turns secondary turnsN_p = No. of primary turms[tex] \\ \\ [/tex]
So:-
[tex] \\ [/tex]
[tex] \dashrightarrow\sf\dfrac{E_s}{E_p}=\dfrac{N_s}{N_p}[/tex]
[tex] \\ \\ [/tex]
[tex] \dashrightarrow\sf\dfrac{E_s}{220}=\dfrac{8}{800}[/tex]
[tex] \\ \\ [/tex]
[tex] \dashrightarrow\sf\dfrac{E_s}{220}=\dfrac{8}{8 \times 100}[/tex]
[tex] \\ \\ [/tex]
[tex] \dashrightarrow\sf\dfrac{E_s}{220}=\dfrac{\cancel8}{\cancel8 \times 100}[/tex]
[tex] \\ \\ [/tex]
[tex] \dashrightarrow\sf\dfrac{E_s}{220}=\dfrac{1}{100}[/tex]
[tex] \\ \\ [/tex]
[tex] \dashrightarrow\sf\dfrac{E_s}{1}=\dfrac{220}{100}[/tex]
[tex] \\ \\ [/tex]
[tex] \dashrightarrow\sf{E_s}=\dfrac{220}{100}[/tex]
[tex] \\ \\ [/tex]
[tex] \dashrightarrow\sf{E_s}=\dfrac{22\cancel0}{10\cancel0}[/tex]
[tex] \\ \\ [/tex]
[tex] \dashrightarrow\sf{E_s}=\dfrac{22}{10}[/tex]
[tex] \\ \\ [/tex]
[tex] \dashrightarrow\bf{E_s}=2.2 \: volt[/tex]
In which beaker was the average kinetic energy of the particles the greatest?
Answer:
The warmer the temperature the more kinetic energy.
Explanation:
The highest temperature
The typical kinetic energy formula is used to comprehend the kinetic energy of a gas. This formula uses the gas's temperature to calculate the kinetic energy, or KE. This is carried out because a gas's kinetic energy is exactly related to its temperature. Thus option D is correct.
What role of average kinetic energy of the particles?Temperature is a gauge for the typical kinetic energy of a substance's constituent particles. It is a particle's typical kinetic energy.
A gas's temperature directly relates to the average kinetic energy of its particles. The particles must travel more quickly as the gas warms since their mass is constant.
The average kinetic energy of the particles in a sample of matter falls as it is continuously cooled. One would anticipate that eventually the particles will stop moving altogether.
Therefore, beaker D: 18 degree Celsius having average kinetic energy of the particles the greatest.
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Photosynthesis Assignment
Use the diagram below to show the cycle of photosynthesis. Include the Sun or energy, carbon dioxide, chlorophyll, water, oxygen and glucose or carbohydrates. Show what happens to each of the elements in carbon dioxide, oxygen and water. Use arrows to show the movement of the substances and label the arrows.
Here are the ways.
First sunlight enters leaves' chlorophyll .Water comes through rootsCarbon dioxide from atmosphereAll combine to form carbohydrates and oxygen After evaporation the tree releases water to atmosphere.Which comes down as rainFirst sunlight enters leaves' chlorophyll . Water comes through roots and Carbon dioxide from atmosphere. All combine to form carbohydrates and oxygen. After evaporation the tree releases water to atmosphere which comes down as rain.
What is photosynthesis?Photosynthesis is a process used by plants and other organisms to convert light energy into chemical energy that, through cellular respiration, can later be released to fuel the organism's activities.
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A rock is thrown downward from the top of a cliff with an initial speed of 12 m/s. If the rock hits the ground after 2.0 s, what is the height of the cliff?
The required height of the cliff is 4.4 m.
Given data:
The magnitude of initial speed of rock is, u = 12 m/s.
The time interval of hitting is, t = 2.0 s.
The given problem is clearly resolved using the concept and fundamentals of second kinematic equation of motion. As per the second kinematic equation of motion we have,
[tex]h =ut+\dfrac{1}{2}(-g)t^{2}[/tex]
Here,
h is the height of cliff.
g is the gravitational acceleration.
Solving as,
[tex]h =(12 \times 2)+\dfrac{1}{2}(-9.8) \times2^{2}\\\\h = 4.4\;\rm m[/tex]
Thus, we can conclude that the required height of the cliff is 4.4 m.
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What is magnetic force??
O A. A force between protons
O B. A force between two poles
O C. A force caused by air particles
O D. A force between objects with mass
Answer:
I believe it's B.
Explanation:
The force that a magnet exerts on certain materials, including other magnets, is called magnetic force. The force is exerted over a distance and includes forces of attraction and repulsion. North and south poles of two magnets attract each other, while two north poles or two south poles repel each other.
A guitar string vibrates with an unknown frequency. If the the guitar string is played along with a 440 Hz tuning fork, a beat frequency of 5 Hz is heard. What are the possible frequencies the guitar string could be vibrating at?
This question involves the concept of the beat frequency.
The possible frequencies of the guitar string could be "445 Hz" (or) "435 Hz".
Beat FrequencyWhen two sounds with a very minor difference in their frequency are played, they produce a frequency equal to the absolute value of the difference between their frequencies. This frequency is known as beat frequency.
[tex]f_b=|f_1-f_2|[/tex]
where,
[tex]f_b\\[/tex] = beat frequency = 5 Hzf₁ = frequency of first guitar string = 440 Hzf₂ = possible frequencies of other string = ?Therefore,
5 Hz = |440 Hz - f₂|
f₂ = 440 Hz ± 5 Hz
f₂ = 445 Hz (OR) 435 Hz
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Please help me
Have you ever sat high in the stadium at a baseball game and heard the sound of a ball being hit by a bat? Did you notice that you heard the sound after you saw the ball being hit?
Explain why you think this happened.
Answer:
Explanation:
The other answer is correct: the act of hitting a ball with a bat creates a sound. You see the act of hitting almost immediately because light travels very fast. The sound on the other hand travels much slower. So if you sit high in the stadium, the sound has to travel for a long distance before reaching you. That is why you hear the sound after you see the ball being hit.
If a car is traveling 100 km/h west and comes to a stop in 3 min, what is the car's acceleration? Need procedure.
Answer:
a = 0.154 [m/s^2]
Explanation:
To solve this problem we must use the following formula of kinematics.
[tex]v_{f}= v_{i}-(a*t)\\[/tex]
where:
Vf = final velocity = 0
Vi = initial velocity = 100 [km/h]
t = time = 3 [min] = 180 [s]
Now we need to convert the velocity from [km/h] to [m/s]
[tex]100[\frac{km}{h} ]*1000[\frac{m}{1km} ]*1[\frac{h}{3600s} ]=27.77[\frac{m}{s} ][/tex]
0 = 27.77 - (a*180)
a = 0.154 [m/s^2]
Note: the negative sign of the equation shows, that the car slows down until it stops
A net torque of magnitude 600 Nm is ex-
erted on the rotor of an electric generator for
31 s.
What is the magnitude of the angular mo-
mentum of the rotor at the end of 31 s if it
was initially at rest?
Answer in units of kg mº/s.
2
How is the potential energy effected as a ball lying on top of a 20 m tall building rolls down to the next
building which is 10 m tall
Answer:
Since the gravitational potential energy of an object is directly proportional to its height above the zero position, a doubling of the height will result in a doubling of the gravitational potential energy. A tripling of the height will result in a tripling of the gravitational potential energy.
Which statement is equivalent to Newton's first law? A. If no net force acts on an object, the motion of the object does not change. B. The force of an object is equal to the mass times its acceleration. C. The unit of force is the newton. D. For every action there is an equal and opposite reaction.
Answer:
A
Explanation:
Hi:)
If no net force acts on an object, the motion of the object does not change. This statement is equivalent to Newton's first law. Hence, option (A) is correct.
What is force?Physics defines force as the push or pull that modifies the velocity of a massed object. The ability to change a body's resting or moving condition is referred to as an external force.
According to Newton's First Law, a body in uniform motion or at rest will remain in that state up to and unless a net external force acts on it.
The key idea here is that an object will maintain a constant velocity if there is no net force produced by unbalanced forces operating on it.
Hence, if no net force acts on an object, the motion of the object does not change. This statement is equivalent to Newton's first law.
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How does a foam-filled winter coat help keep a person warm?
It slows down the transfer of thermal energy from outside to inside the coat.
It slows down the transfer of thermal energy from inside to outside the coat.
It speeds up the transfer of thermal energy from outside to inside the coat.
It speeds up the transfer of thermal energy from inside to outside the coat.
Answer: the answer is B. It slows down the transfer of thermal energy from inside to outside the coat
Explanation: I took the test and got this right:) Hope this helped!!
Answer:
B. It slows down the transfer of thermal energy from inside to outside the coat.
nm
m
s
7 km
ug um t
kg
ms
mg ns us g mm
Arrange the above units in three columns as below.
The units in each column should be in order, with the
largest at the top.
mass
length
time
largest →
unit
why does one end of a nail is wide while the other end is sharp?
What type of image is produced when the object is closer to the lens than the focal point?
diminished or enlarged
virtual or real
upright or inverted
Explanation:
Real images are those where light actually converges, whereas virtual images are locations from where light appears to have converged.
What is the weight of a 215 kg moose?
didn't you just say it's 215
Answer:
Explanation:215 Kilograms =
473.99386 Pounds
(rounded to 8 digits)
The section supports an upward internal shear force and a clockwise internal torque. Where does the absolute maximum shear stress occur?.
The absolute maximum shear stress will occur at : Point A
What is Shear stress ?Shear stress is a force that cause deformation of a material via slippage along planes which are parallel to each other.
From the diagram the shear stress distribution is parabolic in nature therefore the absolute maximum shear stress will occur at points A and C of the diagram.
The shear stress appears maximum at point A due to the shear force and torque
Hence we can conclude that the absolute maximum shear stress will occur at Point A
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Attached below is the missing image related to your question
an object is thrown upward , what is true about the objects upward velocity and acceleration
Answer:
option B is correct
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Potential energy is the energy an object has because of its
why was the triple beam balance invented
Answer:
The triple beam balance is an instrument used to measure mass very precisely. Such devices typically have a reading error of ±0.05 grams. ... The triple beam balance can be used to measure mass directly from the objects, find mass by difference for liquid, and measure out substances.
Which line on the graph represents the accumulation of stable atoms during the decay of a radioactive substance?
Answer:
B. Orange Line
Explanation:
Edge 2021
1. If you move a magnet through a solenoid, an _______
is induced.
Answer:
electromotive force (emf)
Explanation:
Which of the following units could represent acceleration?
a cm/h
b cm/s
c m/h
d km/h?
Answer:
To be precise; well, S.I. Unit of acceleration is m/s.
Which of the following describe an electric motor?
Answer:
B. Changes electrical energy to mechanical energy.
Explanation:
We must make it clear that all the answers are correct, but yet answer B condenses the essence of the main objective of an electric motor. Electrical energy is converted into rotary motion of an axis, that rotational motion is considered a mechanical motion.