The actual weight of the stone is 11 N. It is based on the Archimedes principles.
What is Archimedes principle?Archimedes principle states that the up thrust by water on an object is equal to the weight of water displaced.Upthrust by water on an object= actual weight of object - weight inside waterWhat is the actual weight of the object, if its weight inside water is 9N and weight of water displaced is 2N?Actual weight= weight inside water+ weight of water displaced
= 9N + 2N = 11N
Thus, we can conclude that the actual weight of the object is 11N.
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The combination of an applied force and a friction force produces a constant torque of 36.0 N⋅m on a wheel rotating on a fixed axis. While the force acts for 6.00 s, the angular velocity of the wheel increases from 0 to 10.0 rad/s. The force is removed and the wheel comes to rest in 60.0 s
a. Find the moment of inertia of the wheel.
b. Find the magnitude of the torque due to friction.
c. Find the total number of rotations during the 66.0 s.
d. Find the Kinetic energy of the wheel at 6.00 s when the force is removed.
Answer:
D. Find the kinetic energy of the wheel at 6.00 z when the force is removed.
In the human arm, the forearm and hand pivot about the elbow joint. Consider a simplified model in which the biceps muscle is attached to the forearm 3.80 cm from the elbow joint. Assume that the person's hand and forearm together weigh 15.0 N and that their center of gravity is 15.0 cm from the elbow (not quite halfway to the hand). The forearm is held horizontally at a right angle to the upper arm, with the biceps muscle exerting its force perpendicular to the forearm.
A. Find the force exerted by the biceps when the hand is empty.
B. Now the person holds a 80.0-N weight in his hand, with the forearm still horizontal. Assume that the center of gravity of this weight is 33.0 cm from the elbow. Find the force now exerted by the biceps.
C. Explain why the biceps muscle needs to be very strong.
D. Under the conditions of part B, find the magnitude of the force that the elbow joint exerts on the forearm.
E. Under the conditions of part B, find the direction of the force that the elbow joint exerts on the forearm.
F. While holding the 80.0-N weight, the person raises his forearm until it is at an angle of 53.0∘ above the horizontal. If the biceps muscle continues to exert its force perpendicular to the forearm, what is this force when the forearm is in this position?
G. Has the force increased or decreased from its value in part B? Explain why this is so, and test your answer by actually doing this with your own arm.
Answer:
Answer is explained in the explanation section below.
Explanation:
Part A)
From conserve moment of force, we have:
F1d1 = F2d2
F1 x (3.80 x [tex]10^{-2}[/tex] m) = 15N x (15 x [tex]10^{-2}[/tex] m)
F1 = [tex]\frac{15 . 15 . 10^{-2} }{3.80 . 10^{-2} }[/tex]
F1 = 59.2 N
Force exerted by the biceps when the hand is empty.
Part B)
The 80 N weight acts at 33 cm and 15 N at 15 cm, then the center of mass is:
x = [tex]\frac{m1x1 + m2x2}{m1+m2}[/tex]
x = [tex]\frac{\frac{80}{9.8} (33 .10^{-2}) + \frac{15}{9.8}(15.10^{-2} }{\frac{80}{9.8} + \frac{15}{9.8} }[/tex]
x = 30.16 x [tex]10^{-2}[/tex] m
Total Weight is:
F = 80N + 15N = 95N
From the conserve moment of force, we have:
F ( 3.8 x [tex]10^{-2}[/tex] ) = 95N (30.16 x [tex]10^{-2}[/tex])
F = 754 N
Part C:
From the above two examples solved, the force exerted by the biceps is higher than downward force, due to this muscle need to be very strong.
Part D)
The force exerted by elbow on the forearm is:
The force exerted by the elbow and biceps are in upward direction and total weight is in downward direction. So, the balancing force in vertical direction is:
F2 + 754N = 95N
F2 = 95N -754N
F2 = -659N
Negative sign shows the force is in downward direction.
Part E)
The bicep muscle acts perpendicular to the forearm, so it is lever arm stays the same. but those of the other two forces decreases as the arm is raised. There tension in the biceps muscle decreases.
Part F)
Angle = 53 degrees.
So,
Force = FcosФ
Force = 754 cos 53
Force = 453.76 N
Part G)
The value of force has gone downwards. It has decreased from that of part B.
One species of eucalyptus tree, Eucalyptus regnans, grow to heights similar to those attained by California redwoods. Suppose a bird sitting on top of one specimen of eucalyptus tree drops a nut that is 1.7 ounces. If the speed of the falling nut at the moment it is 50.3 m above the ground is 42.7 m/s, how tall is the tree
Answer:
The tree is 143.325 meters tall
Explanation:
The given parameters of the eucalyptus tree are;
The mass of the eucalyptus tree nut = 1.7 ounces
The speed of the nut at 50.3 m above the ground, v = 42.7 m/s
The equation for free fall is given as follows;
v² = 2·g·h
Where;
v = The velocity after falling through a height, h
g = The acceleration due to gravity = 9.8 m/s²
h = The height through which the seed has already fallen
Therefore, we have;
h = v²/(2·g) = (42.7 m/s)²/(2 × 9.8 m/s²) = 93.025 m
The height through which the seed has already fallen, h = 93.025 m
The height of the tree = h + The height of the seed above ground at the moment it was falling at 42.7 m/s
The height of the tree = 93.025 m + 50.3 m = 143.325 m
The height of the tree = 143.325 m.
The height of the eucalyptus tree is approximately 111.9 meters.
To determine the height of the tree, we can use the equations of motion. The initial velocity of the nut, u, is 0 m/s (since it is dropped), the acceleration due to gravity, a, is approximately 9.8 m/s², and the final velocity, v, is 42.7 m/s. We need to find the height, h. Using the equation v² = u² + 2a(h - u), we can rearrange it to solve for h: h = (v² - u²) / (2a) Plugging in the values, we get: h = (42.7² - 0²) / (2 * 9.8) = 111.9 meters Therefore, the height of the eucalyptus tree is approximately 111.9 meters.
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The map below shows major ocean currents in the North Atlantic and North Pacific Oceans. In general, currents flowing toward the
Equator bring cooler waters to some regions, while currents flowing away from the Equator bring warmer waters to other regions.
North
British
Isles
Askan
North Atlantic
Azor
U.S.A
California
Gulf Stream
Loop
n
Canbean
North Equatorial
North Equatorial CC
North Fuatorial
Equator
South Equatorial
Not
South Equatorial
Image courtesy of NOAA
Judging from the map, which region probably has cooler summers than it would without the effect of a nearby ocean current?
A the Central U.S.
B. the British Isles
C. the U.S. East Coast
D. the US West Coast
Answer:
d
Explanation:
the US West Coast region probably has cooler summers than it would without the effect of a nearby ocean current.
what is ocean current ?
ocean current can be defined as the horizontal movement of seawater which is produced by gravity, wind, and water density, it play an major role in the determination of climates of coastal regions.
The movement of ocean water is continuous which can be up three types such as Waves, Tides, Currents
The streams of water which flow continuously on the ocean surface in specific directions are called ocean currents, it affect the temperature of ocean water as Warm ocean currents increase the temperature whereas Cold ocean currents decrease the temperature.
The magnitude of the ocean currents is about few centimeters per second to as much as 4 metres per second and the intensity of the ocean currents generally decreases with increasing depth.
There are two types of ocean currents such as Warm Ocean Currents
and Cold Ocean Currents
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The ancient Egyptians used the stars to _____.
predict annual flooding
make their calendar
harvest their crops
choose their pharaoh
Answer:
predict annual flooding
Answer:
I'm pretty sure it is b make their calander
Semiconductors can simplistically be thought of as an intermediate state between insulators and conductors. In a semiconductor, charges are normally bound in place (like in an insulator), but when injected with enough energy, the charges can move freely (like in a conductor). Given what we have observed about the behavior of conductors and insulators in this exploration, what would happen if we replaced the glass rod with a semiconductor material
Answer:
The semiconductor rod will conduct electricity
Explanation:
Glass rod does not conduct electricity. Glass is one of the best insulators of electricity. But when a glass rod is replace with a semi conductor, then the semi conductor rod starts conducting electricity as the electrons are free to move.
Semi conductors are special materials in which the energy band lies in between the conductor and the non conductor. The conductivity of a semi conductor increases with the increasing temperature.
In an semi conductor the electrons are free to move and as they starts moving they conduct electricity. Thus a semi conductor rod replacing a glass rod conducts electricity.
If a shopping cart is pushed by a person exerting 50 J of work on it, what is the energy transfer to the shopping cart if it has a mass of 2 kg?
A. 52 J
B. 50 J
C. 25 J
Answer:
B
Explanation:
A car starts from rest at a stop sign. It accelerates at 2.0 m/s2 for 6.2 seconds, coasts for 2.5 s , and then slows down at a rate of 1.5m/s2 for the next stop sign. How far apart are the stop signs
Answer:
the distance between the stop signs is 120.7 m.
Explanation:
The car moved in three stages;
(1) It accelerates from rest at 2.0 m/s² for 6.2 seconds
(2) it moved at a constant speed for 2.5 s
(3) it finally decelerate at the rate of 1.5m/s²
(1) The distance moved by the car during the first stage;
s₁ = ut + ¹/₂at²
s₁ = 0 + ¹/₂ (2)(6.2)²
s₁ = 38.44 m
(2) The distance moved by the car during the second stage;
calculate the constant speed of the car,
v = u + at
v = 0 + 2 x 6.2
v = 12.4 m/s
The distance moved by the car as it coasts for 2.5s: s₂ = vt
s₂ = 12.4 x 2.5
s₂ = 31 m
(3) The distance moved by the car during the third stage;
When the car stops, the final velocity is zero.
v² = u² + 2as₃
a = -1.5 m/s², since the car slowed down or decelerated.
0 = 12.4² + (2 x - 1.5)s₃
0 = 153.76 - 3s₃
3s₃ = 153.76
s₃ = 153.76 / 3
s₃ = 51.253 m
The total distance moved by the car from the start to stop = s₁ + s₂ + s₃
d = 38.44 m + 31 m + 51.253 m
d = 120.7 m
Therefore, the distance between the stop signs is 120.7 m.
Plzz answer correctly
Answer:
B.
Explanation:
two small identical conducting spheres have charges of 2.0x10-9C and - 0.5x109 C respectively when they are placed 4cm apart, what is the force between them? If they are brought into contact and then separated by 4cm, what is the force between them?
Answer:
6
Explanation:
nothingnsbejejjdbsbzbawkje
Which image represents a transverse mechanical wave?
Answer:
A
Explanation:
It is kinda like a spring.
The image which represents a transverse mechanical wave is A.
What is a mechanical wave?The wave has motion if all points on a wave vibrate at right angles to the direction of the wave propagation.
A transverse wave is a mechanical wave which is much like sinusoidal wave which has particles vibrating about their equilibrium position perpendicular to the direction of the motion of the wave.
Hence, the image which represents a transverse mechanical wave is A.
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Plzz answer correctly
at
same
5N
12N
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act
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resultant
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9.
b.
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force.
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Answer:
b
Explanation:
this because if force (f) are resultant cos then the point is proportional to the direction of c at greatest possible forces
An iron block of 12 kg undergoes a process during which there is a heat gain from the block at 2 kJ/kg, an elevation increase of 32 m, and a decrease in velocity from 40 m/s to 7 m/s. During the process, which also involves work transfer, the internal energy of the block increases by 70 kJ. Suppose the total energy of the system remains constant. Determine the work transfer during the process in kJ and indicate whether the work is done on/by the system.
Answer:
Explanation:
Total heat gain by the block ΔQ = 2 x 12 kJ = 24 kJ .
Gain of potential energy = mgh = 12 x 9.8 x 32 = 3.763 kJ
Decrease in kinetic energy KE = 1/2 x 12 ( 40² - 7² )
= 9.306 kJ
increase in internal energy ΔE = 70 kJ
ΔQ = ΔE + PE - KE + W , W is work done by the gas
Putting the values
24 = 70 + 3.763 - 9.306 + W
W = - 40.457 kJ .
Since W is negative that means work is done on the system .
Your bike is too big if your can't touch the ground A.Knees B.Hands C.Feet
Answer: C: Feet
Explanation: Why...
A woman accidentally drops a flowerpot from a windowsill at a height d above the street towards a man of height h standing below. The woman calls out to the man in just enough time for the man to move out of the way. If the man needs a time interval of Δt to respond to the warning, at what height above the street will the flowerpot be when the woman calls out the warning? (Use the following as necessary: d, h, Δt, v for the speed of sound, and g for gravitational acceleration.)
Answer:
h^2 - ( 2t_o v_s + 2v_s^2 /g) h + v_s^2 \ t_o^2 =0
The correct result is that of a positive height
Explanation:
For this exercise we use the kinematic relations, let's start by finding the time it takes for the sound to reach the man
v_s = y / t
t = [tex]\frac{y}{ v_s}[/tex]
this height is y = h
t = \frac{h}{ v_s}
the man has a response time of t = t₀, therefore
time to move is
t' = t - t₀
the initial height of flower pot is
y = y₀ + v₀ t' - ½ g t'²
when it reaches the floor the height is zero y = 0 and as the pot is dropped its initial velocity is zero v₀ = 0
0 = y₀ +0 - ½ g (t -t₀)²
if the initial height is i = h,
h = ½ g ([tex]\frac{h}{v_s}[/tex] - t₀)²2
[tex]\frac{2}{g} h[/tex] = [tex]\frac{h^2}{v_s^2}[/tex] - [tex]\frac{2t_o }{v_s} h[/tex] + t₀²
[tex]\frac{h^2}{v_s^2} - ( \frac{2t_o}{v_s} + \frac{2}{g} ) h + t_o^2 = 0[/tex]h2 / vs2 - (2nd / vs + 2 / g) h + to2 - = 0
[tex]h^2 - ( 2t_o v_s + 2v_s^2 /g) h + v_s^2 \ t_o^2 =0[/tex]
To know the height, you must solve the second degree equation, it is much easier with numerical values.
The correct result is that of a positive height
cylindrical electric resistance heater has a diameter of 1cm and length of 0.25m. When air at 25oC flows across the heater a heat-transfer coefficient of 25W/(m2 . oC) exists at the surface. (JUSTIFY ANY ASSUMPTIONS YOU IMPOSE!) a) If the electrical input to the heater is 5W, what is the steady state surface temperature of the heater if radiation is assumed negligible
Answer:
Explanation:
From the information given:
The diameter of the cylindrical heater (d) = 1 cm
The length of the cylindrical heater (l) = 0.25 m
The ambient air temperature [tex](T_{\infty})[/tex] = 25° C= (273+25)K = 298 K
The convective heat transfer coefficient (h) = 25 W/m² °C
The electric input Q = 5W
As stated in the question that if radiation is being neglected:-
Let also assume that;
the heat transfer takes place at a steady-state
1-D flow takes place
No external heat generation; &
No force convection takes place;
Then; the heat transfer through the convection can be calculated as:
[tex]Q = hA(T - T_{\infty})[/tex]
[tex]5= 25 \times (\pi \times (1\times 10^{-2}) \times 0.25) (T -0.25)[/tex]
By solving the above calculation:
T ( surface temperature of the heater) = 50.46° C 122.83° F
Which of the following diagrams would be a good, strong magnet?
A 0.15 kg baseball is traveling at 40 meters per second (about 90 miles per hour) if the ball comes to a complete stop when it hits the catchers mitt, what is the change in velocity?
Answer:
Please find attached pdf
Explanation:
Which statement best compares coal and ores?
Both are burned for energy.
Both take millions of years to form.
Both require oxygen to form.
Both are used to make coins.
Answer:
Option 2 both take millions of years to form
Explanation:
Both coal and ores take millions of years to form.
What are ores?Ore is a naturally occurring rock or silt that has precious minerals in it that may be extracted, processed, and sold for a profit. These minerals are usually metals. Mining is the process of removing ore from the soil. The valuable metals or minerals are then removed by treating or refining the ore, frequently through smelting.
The concentration of the desired ingredient in an ore is referred to as its grade. To decide if a rock has a high enough grade to be worth mining and is therefore regarded as an ore, the value of the metals or minerals it contains must be evaluated against the expense of extraction.
Typically, oxides, sulphides, silicates, or native metals like copper or gold are the minerals of interest. To separate the valuable components from the waste rock, ore must be treated. Numerous geological processes collectively known as ore genesis are responsible for the formation of ore deposits.
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Q4. (a) An acre-foot is the volume of water that would cover 1 acre of flat land to a depth of 1
foot. How many gallons are in 1 acre-foot?
Answer:
326,000
Explanation:
One acre-foot equals about 326,000 gallons, or enough water to cover an acre of land, about the size of a football field, one foot deep. An average California household uses between one-half and one acre-foot of water per year for indoor and outdoor use.
Although 0 dB is often referred to as the lower threshold of human hearing, it is important to realize that the human ear is not equally sensitive to all frequencies of sound. In other words, a particular noise may sound louder or softer depending on the frequency of the sound wave being transmitted. Because of this variation, scientists have defined a unit of loudness, called a phon, to represent the intensity of sound waves with a frequency of 1000 Hz. A 60-phon sound is one that is perceived by the human ear to have the same loudness as a sound wave with an intensity of 60 dB and a frequency of 1000 Hz.
Required:
a. At approximately what frequency do most people perceive the least intense sounds? Answer numerically in hertz to two significant figures.
b. Normal conversation has a sound level of about 60 dB. How many times more intense must a 100-Hz sound be compared to a 1000-Hz sound to be perceived as equal to 60 phons of loudness?
Answer:
20 Hz
15.8 times
Explanation:
A
Although the range of frequency for any human's ear is usually said to be between 20 Hz and 20 kHz. And since the question asked for the least intense frequency, that has to be 20 Hz. Essentially the frequency most people perceive the least intense sound is 20 Hz.
B
A 100-Hz sound must be 10^1.2 times or 15.8 times more intense compared to a 1000-Hz sound to be perceived as equal to 60 phons of loudness
A Van de Graaff generator is one of the original particle accelerators and can be used to accelerate charged particles like protons or electrons. You may have seen it used to make human hair stand on end or produce large sparks. One application of the Van de Graaff generator is to create x-rays by bombarding a hard metal target with the beam. Consider a beam of protons at 1.10 keV and a current of 4.65 mA produced by the generator.
(a) What is the speed of the protons?
(b) How many protons are produced each second?
Solution :
Given that :
The energy of the protons, K.E. = 1.10 keV
[tex]$= 1.10 \times 10^3 \ eV $[/tex]
The current produced by the generator is I = 5 mA
[tex]$= 5 \times 10^{-3} \ A$[/tex]
Now [tex]$1 \ eV = 1.6 \times 10^{-19 }\ J$[/tex]
Mass of the proton, m = [tex]$1.67 \times 10^_{-27} $[/tex] kg
Charge of the proton, [tex]$q_p = 1.6 \times 10^{-19} \ C$[/tex]
a). Therefore using the formula for K.E. we can find out the velocity of the proton.
[tex]$K.E. =\frac{1}{2}mv^2$[/tex]
[tex]$v=\sqrt{\frac{2K.E.}{m}}$[/tex]
[tex]$v=\sqrt{\frac{2\times 10^3 \times 1.6 \times 10^{-19}}{1.67 \times 10^{-27}}}$[/tex]
[tex]$= 4.38 \times 10^5 \ m/s$[/tex]
b). We know that the current is :
[tex]$I=\frac{\Delta Q}{\Delta t}$[/tex]
Therefore, the total charge in one second is given by :
[tex]$\Delta Q = I \times \Delta t$[/tex]
[tex]$= 5 \times 10^{-3} \times 1$[/tex]
[tex]$= 5 \times 10^{-3}\ C$[/tex]
So, the number of protons in this charge is given by :
[tex]$n = \frac{\Delta Q}{q_p}$[/tex]
[tex]$=\frac{5 \times 10^{-3} }{1.6 \times 10^{-19}}$[/tex]
[tex]$= 3.13 \times 10^{16}$[/tex] protons
Assuming 84.0% efficiency for the conversion of electrical power by the motor, what current must the 13.0-V batteries of a 716 kg electric car be able to supply to climb a 3.00 x 102 m high hill in 2.00 min at a constant 22.0 m/s speed while exerting 7.00 x 102 N of force to overcome air resistance and friction
Answer:
[tex]\mathbf{ current(I) =1766.67 \ A}[/tex]
Explanation:
Given that:
The air resistance and friction = 700 N
The gravity caused force = 716 × 9.8 = 7016.8
Total force = (7016.8 + 700) N
Total force = 7716.8 N
∴
[tex]13 \times current(I) \times 0.84 = \dfrac{7716.8 \times 300}{2 \times 60}[/tex]
[tex]current(I) \times 10.92= 19292[/tex]
[tex]current(I) = \dfrac{19292}{10.92}[/tex]
[tex]\mathbf{ current(I) =1766.67 \ A}[/tex]
Which describes increasing the efficiency of an energy resource?
switching from coal to solar
making cars that get better gas mileage
using biomass instead of coal
turning off the lights when leaving a room
Answer:
making cars that get better gas mileage
Answer: Making cars that get better gas
Explanation: Gradpoint
Which of the following is a part of both geocentric model and heliocentric model
Answer:
These planets rotate around the sun in a circular path. Likewise in a heliocentric model it is believed that the sun is at the center of the universe and the planet earth along with all other planet move around it. Thus in both geocentric model and heliocentric model bodies in space move in circular orbits.
Answer:
The bodies in space move in circular orbits
Explanation:
I got it right on my test
Stacy collected the data shown in the table.
Number of Washers Total Mass Total Force
0.6 kg 5.9 N
2
1.2 kg 11.8 N
3
1.8 kg 17.6N
4
2.5 kg 24.5 N
5
3.2 kg 31.4 N
What's the general relationship between mass and gravitational force?
Answer:
1.8 Kg 17.6N
Explanation:
I don't know the explanation hahaha
Answer:
The gravitational force on an object increases as the object’s mass increases.
Explanation:
This is the answer on Edmentum. :)
energy in a stretched spring
Answer:
Elastic potential energy is the potential energy stored by stretching or compressing an elastic object by an external force such as the stretching of a spring. It is equal to the work done to stretch the spring which depends on the spring constant k and the distance stretched.
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Two students on ice skates stand one behind the other. Student 2 pushes student 1 in the back; student 1 has less mass than student 2; student 1 has a great acceleration than student 2. which law of motion is this (Newton's laws)
Answer:
law in acting
Explanation:
What was the average speed in km/h of a car that travels 788 km in 7.1 h?
Answer:
Well the answer is 111 (rounded) km/h
Explanation:
788/7.1 is 110.9... so if you round it it would equal 111.