Given :
A weight lifter lifts a 280-N set of weights from ground level to a position over his head, a vertical distance of 1.60 m.
To Find :
How much work does the weight lifter do, assuming he moves the weights at constant speed.
Solution :
We know, work done is given by :
[tex]W= Fdcos\ \theta[/tex]
Here, F = 280 N and d = 1.60 m
Since, weight lifer is applying and upward force and displacement is also in upward direction.
[tex]\theta = 0^{\circ}\\cos\ 0^{\circ} = 1[/tex]
Putting all these in above equation, we get :
[tex]W = 280\times 1.6\times 1\\\\W = 448\ J[/tex]
Therefore, work done by weight lifter 448 J.
Hence, this is the required solution.
Ethan drove a 1500 kg car around a circular track with a radius of 75 m. If the magnitude of the centripetal acceleration is 2 m/s2, what is the car's speed?
A)2.25 m/s
B)20 m/s
C)37.5 m/s
D)150 m/s
Answer:
12.25 m/s
Explanation:
The following data were obtained from the question:
Mass (m) = 1500 Kg
Radius (r) = 75 m
Centripetal acceleration (a) = 2 m/s²
Velocity (v) =?
Centripetal acceleration (a) is related to the velocity (v) and radius (r) according to the following formula:
a = v²/r
Thus, we can obtained the velocity of the car by using the above formula as illustrated below:
Radius (r) = 75 m
Centripetal acceleration (a) = 2 m/s²
Velocity (v) =?
a = v²/r
2 = v²/75
Cross multiply
v² = 2 × 75
v² = 150
Take the square root of both side.
v = √150
v = 12.25 m/s
Thus, the speed of the car is 12.25 m/s.
describe how you would measure the diameter of a tennis ball
A plant dying after being exposed to poison represents a physical change.
True
False
Answer:
It does not represent a physical change
Answer:
chemical change as death is irreversible
ke...
11. Table salt, NaCl, is a classic binary ionic compound. (4 points)
a. What is the oxidation number of Na? Of Cl?
ave...
Answer:
+1
-1
Explanation:
The oxidation number of Na in NaCl is +1 and that of Cl is -1.
For simple ions, the oxidation number is the charge they carry.When NaCl is oxidized we have;
NaCl → Na⁺ + Cl⁻
In this process, Na will lose an electron to become Na⁺ and thus isoelectronic with Ne, Cl will gain the electrons to become Cl⁻ and thus isoelectronic with Argon.
Plant cells have It is used for photosynthesis
If you had a string tied firmly to a post, and you created a wave that went down the string, why do you think would happen as the wave reached the post?
A.
B.
C.
D.
Electricity is produced in a hydroelectric plant when moving water turns a turbine.
Which describes this energy transformation from the turning turbine to electricity?
A
kinetic energy into electric energy
B
nuclear energy into electrical energy
С
thermal energy into electric energy
chemical energy into electric energy
Answer:
It involves both energy transformation and energy transfer.
Explanation:
In the hydroelectric power plant, the energy is transformed from kinetic energy to electricity. Therefore, option (A) is correct.
How is the energy transformed in the hydroelectric power plant?In the hydroelectric power plant, electric energy is generated using water from a turbine. The moving water is used to propel the turbines. At first, a large amount of the flowing water is stored across the dams. The kinetic energy of moving water is stored as potential energy in the dams.
Then the stored water will fall on the turbines and rotate the turbines which causes the potential energy of water to be used to turn the turbines which is mechanical energy.
Therefore, the potential energy of water is converted into mechanical energy. Then the rotating turbines generate electricity and the mechanical energy is converted into electrical energy.
Therefore, the hydroelectric power plant converts the kinetic energy of water into electrical energy.
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3) the maximum angular displacement of a pendulum in simple harmonie motion is theta,max then the
kinetic energy is equal to the potential energy when the angular displacement is given by
Answer:
B is correct
Explanation:
Maximum Kinetic energy= Work done.
Now, Work done=mgh=mg(L−Lcosθ)=mgL(1−cosθ)
Option B is thus correct.
an inductive argument guarantees its conclusion
True
False
Answer:
False
Explanation:
inductive arguments have some evidence but do not have full assurance of truth of the conclusion
what is the state of y when y = k/x, x is halved.
Answer:
y becomes doubled.
Explanation:
If;
y = [tex]\frac{k}{x}[/tex]
what is the state of y when x is halved;
the given expression is an inverse relationship. When y increases, x is supposed to decrease and vice versa.
if x is halved; x = [tex]\frac{x}{2}[/tex]
[tex]\frac{k}{\frac{x}{2} }[/tex] = [tex]\frac{2k}{x}[/tex]
Now compare :
[tex]\frac{k}{x}[/tex] : [tex]\frac{2k}{x}[/tex]
we see that y becomes doubled
If you measured the final velocity of the car to be 1 m/s and the initial mass of the car remains the same, how much coal was added to the car in kg
Complete Question
The complete question is shown on the first uploaded image
Answer:
a
[tex]p = 14033.7 \ kg\cdot m/s[/tex]
b
[tex]v = 1.22 \ m/s[/tex]
c
[tex]m_2 = 9506.7 \ kg[/tex]
Explanation:
From the question we are told that
The mass of the coal car is [tex]m_1 = 4527 \ kg[/tex]
The velocity is [tex]v_i = 3.1 \ m/s[/tex]
The load of coal dropped is [tex]m_2 = 6952 \ kg[/tex]
Generally the momentum of the system before the coal is added is mathematically represented as
[tex]p = m_j * v_i[/tex]
=> [tex]p = 4527 * 3.1[/tex]
=> [tex]p = 14033.7 \ kg\cdot m/s[/tex]
Generally from the law of momentum conservation is mathematically represented as
[tex]m_1 * v_i + m_2 * v_2 = (m_1 + m_2 )v[/tex]
Here [tex]v_2[/tex] is the velocity of the load before it is dropped and the value is 0 m/s
So
=> [tex]v =\frac{m_1 * v_i }{m_1 + m_2}[/tex]
[tex]v = \frac{4527 * 3.1 }{( 4527 + 6952 )}[/tex]
=> [tex]v = 1.22 \ m/s[/tex]
When v = 1m/s and [tex]m_1[/tex] remain the same
Then
=> [tex]1 =\frac{4527 * 3.1 }{4527 + m_2}[/tex]
=> [tex]4527 + m_2 = 14033.7[/tex]
=> [tex]m_2 = 9506.7 \ kg[/tex]
Which statement is part of Dalton's atomic theory?
Matter is composed of small particles called atoms.
Atoms can be divided into their subatomic particles.
Atoms are able to be seen with proper spectroscopy equipment.
Chemical reactions can change atoms from one type to another.
Answer:
Dalton’s atomic theory was a scientific theory on the nature of matter put forward by the English physicist and chemist John Dalton in the year 1808. It stated that all matter was made up of small, indivisible particles known as ‘atoms’.
Explanation:
Atoms can be divided into their subatomic particles.
The statement that is part of Dalton's atomic theory is as follows: Matter is composed of small particles called atoms.
What is Dalton's atomic theory?John Dalton is a scientist that first stated the theory of chemical combination in 1803.
The components of these theory are as follows:
Elements consist of indivisible small particles called atoms.All atoms of the same element are identical i.e. different elements have different types of atom. Atoms can neither be created nor destroyedTherefore, according to this question, the statement that is part of Dalton's atomic theory is as follows: Matter is composed of small particles called atoms.
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Only mirrors reflect light? True or false?
False - Every object which is not transparent and translucent reflect light. In order to see colours, the object absorb light and reflect the light we see.
Doing specific exercises to improve a particular skill or type of health fitness is called training? True or false
Which material is a composite? A. gold B.silicon C.polycarbonate D.aluminum
Answer:
Correct answer is polycarbonate not gold
Explanation:
Which state of matter does this model represent?
Image of particles tightly packed
Solid
Liquid
Gas
Plasma
Answer:
gas
Explanation:
it is gas because the particles are floating up none of the above would be floating up.
Answer:
Solid
Explanation:
A: Solid- Solids have the particles tightly packed. They have a definite shape and volume
B: Liquid- Liquids have particles not to tightly packed but kind of loose. They have an indefinite shape but a definite volume
C: Gas- Gas has particles freely all around. Indefinite shape and volume
D: Plasma- Plasma is different and should be explained with an example; think of lighting....
Since the image shows tightly packed particles, it is clear the answer is a solid.
A good alternative to sit ups is
A. Crunches
B. Leg Raises
C. Side Twists
When are zeros significant when found to the trailing (to the right) of the decimal point?
Answer:
Usually, zeroes are found to the right of a decimal point in significant numbers if you have something like [tex]7\frac{1}{100000000000000000000000000}[/tex] (exaggerated example of course), which is when you have a number that is very very close to the integer before it, but isn't that integer.
where was the position of the singularity before the big bang ?
What magnification would be obtained if an eyepiece with a focal length of 0.38 m was placed on telescope?
Answer:
This question is incomplete
Explanation:
This question is incomplete because the telescope's focal length was not provided. The formula to be used here is
Magnification = telescope's focal length/eyepiece's focal length
The eyepiece's focal length was provided in the question as 0.38 m.
NOTE: Magnification can be described as the power of an instrument (in this case telescope) to enlarge an object. It has no unit and thus the two focal lengths mentioned in the formula above must be in the same unit (preferably meters since one of them is in meters already).
Hurry please
The distance from wave to wave is called what
Answer:
Wavelength
Explanation:
I NEED HELP ASAP MY LAB REPORT IS DUE TOMORROW ND MY BRAIN STOPPED WORKING HOURS AGO!!!
please explain the physics behind one of those coin wishing well funnels
like angular momentum, torque, centripetal force, gravity, and inertia
PLEasseee
Answer:
When the coin rolls down the ramp, it acquires a tangential velocity, and so travels in circles around the wishing well. As gravity pulls the coin down the curve, the circles get smaller. Since angular momentum must be conserved, the coin's speed increases as it goes further down the funnel.
Fast and safe heart rate for workouts is called muscular strength? True or false
Answer:
False
Explanation:
Answer:
false :3
hope this helps
Please help answer 1,2,3.

Answer:
gbh
Explanation:
What part of the body acts as levelers
Answer: your feet are the foundation! Even though all your body parts are connected and affect one another, your feet are what we at Foot Levelers call, the "foundation".
Explanation:
A 50 N girl climbs the flight of stairs in 3 seconds. How much work does she
perform? How much power does she use? *
A man driving a car at 35 mph hits his brakes suddenly to avoid hitting a dog.
Everything in the front seat of his car slides forward and into the floorboard. Which of
Newton's laws does this illustrate?
Answer:
Inertia; Newton's First Law
Explanation:
When you hit you're breaks, the force you feel that pulls you forward is due to inertia.
Newton's first law says that "every object will remain at rest or in uniform motion in a straight line unless compelled to change its state by the action of an external force." The question is a perfect example of this.
It is due to the inertia of motion of the objects that they fall on the floor bed. This is also called Newton's first law of motion.
What is the name of Newton's first law of motion?Newton's first law of motion is known as the law of inertia.
Given is a man who is driving a car at 35 mph hits his brakes suddenly in order to avoid hitting a dog. During the incident, everything in the front seat of his car slides forward and into the floorboard.
The property of body by virtue of which it resist any change in its state of rest or uniform motion is called inertia of body. When the car was moving at 35 mph, every object on front seat was also moving with the same speed. However, when the brakes were applied, they were applied on the car and not on the objects in the front seat. Hence, they keep moving forward and stop only when they strike and fall down. This is called inertia of motion. This is Newton's first law of motion.
Therefore, it is due to the inertia of motion of the objects that they fall on the floor bed. This is also called Newton's first law of motion.
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Suppose that the potential energy of a body at a certain height is 200 J. If the body falls, what is its kinetic energy just as it reaches the ground?
Answer:
200j
Explanation:
The kinetic energy just as it reaches the ground is 200J.
What is Potential energy?Potential energy is defined as the energy stored within an object that exists as a result of the state, position or arrangement of the object. It is one of the two primary forms of energy while the other is kinetic energy. The stored energy is released when there is a change in the state, position or arrangement of the object.
This is the stored energy which depends upon the relative position of various parts of a system such as a spring has more potential energy when it is compressed or stretched.
Initially the potential energy of the body is 200 J but when it is released, its potential energy is converted into kinetic energy. When the body just touches the ground, the kinetic energy becomes equal to the potential energy.
Thus, the kinetic energy just as it reaches the ground is 200J.
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A robot that is exploring the surface of a planet has a mass of 120.4 kg. If the
gravitational force acting on the robot is 655.2 N downward, what is the robot's free-
fall acceleration?
Answer:
4.65.3 heehiwijwjwwjwhh
Explanation:
behsjjejejnndjjje
Answer:
D
Explanation:
An archer shoots an arrow. Consider the action force to be the bowstring against the arrow. The reaction to this force is the:_____________
a. friction of the ground against the archer's feet.
b. grip of thhe archer's hand on the bow.
c. arrow's push against the bowstring.
d. combined weight of the arrow and bowstring
e. air resistance against the bow arrow.
Answer:
c. arrow's push against the bowstring.
Explanation:
Newtons third law of motion describe the relationship between action and reaction forces. Thus when the action force is applied by the bowstring against the arrow, a reaction to this force is supplied by the arrow's push against the bowstring.
If these two forces are not equal and opposite, the arrow would not move as expected. The elastic property of the bowstring propels the arrow at a rate which is due to the potential energy it has gained due to the stretching force.
