Answer:
Q = 189000 [J]
Explanation:
The internal energy or heat can be calculated by means of the following expression.
[tex]Q=m*c_{p}*DT[/tex]
where:
Q = internal energy or heat [J]
m = mass = 15 [kg]
Cp = 840 [J/kg*°C]
DT = temperature change = 15 [°C]
[tex]Q = 15*840*15\\Q = 189000 [J][/tex]
A solid sphere made of plastic density of 1350 kg/m3 has a radius of 35.0 cm. It is suspended by a massless cord. 75% of its volume is in water and 25% of it is in oil. The density of water is 1000 kg/m3 and the density of the oil is 850 kg/m3. What is the total buoyant foce on the sphere
Answer:
B_total = 1694 N , T = - 937.7 N
Explanation:
This is an exercise of the Archimedes principle that establishes that the thrust of a liquid is equal to the weight of the dislodged volume
B = ρ g V_body
For this case we will assume that the weight of the body is in equilibrium with the thrust of the liquids and the tension of the rope
B₁ + B₂ - W + T = 0
suppose liquid 1 is water and liquid 2 is oil
ρ₁ g V₁ + ρ₂ g V₂ = W
for body weight let's use the definition of density
ρ = m / V
m = ρ V
we substitute
T = ρ g V - (ρ₁ g V₁ + ρ₂ g V₂)
In the problem we are told that the volume in the water is 75% and the volume in the oil is 25% of the body's volume.
T = ρ g V - g (ρ₁ 0.75 V + ρ₂ 0.25 V)
let's calculate the volumes
Body
V = 4/3 π r³
liquid 1 (water)
V₁ = 0.75 V = ¾ V
liquid 2 (oil)
V₂ = 0.25 V = ¼ V
we substitute
T = ρ g [tex]\frac{4}{3}[/tex] π r³ - g (ρ₁ [tex]\frac{3}{4}[/tex] [tex]\frac{4}{3}[/tex] π r³ + ρ₂ [tex]\frac{1}{4}[/tex] [tex]\frac{4}{3}[/tex] π r³)
T = [tex]\frac{4}{3}[/tex] ρ g r³ - g π r³ (ρ₁ + [tex]\frac{1}{3}[/tex] ρ₂)
The term of the floating force is
B_total = g π r³ (ρ₁ + [tex]\frac{1}{3}[/tex] ρ₂)
let's calculate its value
B_total = 9.8 π 0.35³ (1000 + ⅓ 850)
B_total = 1694 N
therefore the tension in the string is
T = [tex]\frac{4}{3}[/tex] 1350 9.8 0.35³ - 1694
T = 756.3 - 1694
T = - 937.7 N
The negative sign indicates that the system tends to come out of the liquid, for which a downward force must be applied to keep it in position.
using the forces applied to the system, determine the mechanical advantage of this pulley
A) 0.5
B) 2.0
C) 50
D) 100
Answer: the answer is B. 2.0
Explanation:
why did the following change occur? the snow that covered the ground all winter began to melt, temperatures rose, and flowers started to bloom
A.) Days became shorter.
B.) The Earth tilted away from the sun
C.) The sun's rats became for concentrated.
D.) Earth completed one revolution
Answer:C
Explanation:
Answer:
B
Explanation:
Because the earth shifts axes points so it would make it cllser hotter etc
The energy flow per unit time per unit area (S) of an electromagnetic wave has an average value of 310 mW/m2. The maximum value of the magnetic field in the wave is closest to:
Answer:
5.096*10^-8
Explanation:
Given that
The average value of the electromagnetic wave is 310 mW/m²
To find the maximum value of the magnetic field the wave is closest to, we say
Emax = √Erms
Emax = √[(2 * 0.310 * 3*10^8 * 4π*10^-7)]
Emax = √233.7648
Emax = 15.289
Now, with our value of maximum electromagnetic wave gotten, we divide it by speed of light to get our final answer
15.289 / (3*10^8) = 5.096*10^-8 T
Suffice to say, The maximum value of the magnetic field in the wave is closest to 5.096*10^-8
The sound level at a distance of 1.48 m from a source is 120 dB. At what distance will the sound level be 70.7 dB?
Answer:
The second distance of the sound from the source is 431.78 m..
Explanation:
Given;
first distance of the sound from the source, r₁ = 1.48 m
first sound intensity level, I₁ = 120 dB
second sound intensity level, I₂ = 70.7 dB
second distance of the sound from the source, r₂ = ?
The intensity of sound in W/m² is given as;
[tex]dB = 10 Log[\frac{I}{I_o} ]\\\\For \ 120 dB\\\\120 = 10Log[\frac{I}{1*10^{-12}}]\\\\12 = Log[\frac{I}{1*10^{-12}}]\\\\10^{12} = \frac{I}{1*10^{-12}}\\\\I = 10^{12} \ \times \ 10^{-12}\\\\I = 1 \ W/m^2[/tex]
[tex]For \ 70.7 dB\\\\70.7 = 10Log[\frac{I}{1*10^{-12}}]\\\\7.07 = Log[\frac{I}{1*10^{-12}}]\\\\10^{7.07} = \frac{I}{1*10^{-12}}\\\\I = 10^{7.07} \ \times \ 10^{-12}\\\\I = 1 \times \ 10^{-4.93} \ W/m^2[/tex]
The second distance, r₂, can be determined from sound intensity formula given as;
[tex]I = \frac{P}{A}\\\\I = \frac{P}{\pi r^2}\\\\Ir^2 = \frac{P}{\pi }\\\\I_1r_1^2 = I_2r_2^2\\\\r_2^2 = \frac{I_1r_1^2}{I_2} \\\\r_2 = \sqrt{\frac{I_1r_1^2}{I_2}} \\\\r_2 = \sqrt{\frac{(1)(1.48^2)}{(1 \times \ 10^{-4.93})}}\\\\r_2 = 431.78 \ m[/tex]
Therefore, the second distance of the sound from the source is 431.78 m.
Draw the Free- Body diagram of the 37 kilogram glass falling to the floor in a vacuum.
Then, use Newton’s Second Law to calculate how much force the glass hits the floor with.
Answer:
362.6 N
Explanation:
[tex]F_{g}=mg[/tex]
[tex]F_{g}=37\cdot9.8[/tex]
[tex]F_{g}=362.6\ N[/tex]
Therefore, the force that the glass hits the floor with is 362.6 N
A 40-kg person is climbing 3 m up a flight of stairs in 6 seconds. How much work did they do climbing the stairs? (acceleration due to gravity = 10 m/sec2)
Answer:
1200J
Explanation:
W.D=mass×accelerarion due to gravity×distance
W.D=40kg×10m/s²×3m
W.D=1200kgm²/s²
W.D=1200J
A 40 kg person is climbing 3 m up a flight of stairs in 6 seconds, then the work done by the person to climb the stairs is 1200 J.
What is Work done?When we apply a force called "F" to a block, the body moves with an acceleration or, additionally, its speed changes depending on the force's direction. The system's kinetic energy changes depending on whether the speed increases or decreases.
Energy must be transformed into another form because, as far as we are aware, it cannot be created or destroyed. In this view, it is referred to as work completed.
[tex]Work\ done = Force*Distance[/tex]
and Force = mg
Substitute all the values in the above formula,
W.D = 40 kg × 10 m/s² × 3 m
W.D = 1200 kg m²/s² or,
W.D = 1200 J
To get more information about Work done :
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what is the shallowest part of the ocean ecosystem is called
Answer:
intertidal zone.
the shallowest part of the ocean ecosystem, where the ocean floor os covered and uncovered as the tide goes in and out. Plankton. the organisms that float on the water in aquatic ecosystems and are unable to swim.
1. Answer the question below. Use the rubric in the materials for help if needed.
Devon drove 50 miles west and then drove 15 miles north. Determine Devon's displacement. Show your work.
I need help
Answer:
d = 52.20 miles
Explanation:
Given that,
Devon drove 50 miles west and then drove 15 miles north.
We need to find Devon's displacement. Let it is d. It can be calculated as follows :
[tex]d=\sqrt{50^2+15^2} \\\\=52.20\ \text{miles}[/tex]
Hence, Devon's displacement is 52.20 miles.
I AM 145 LBS. I FELL FROM A TABLE TOP THAT WAS 4.5 FEET HIGH AND LANDED ON MY HAND WHICH WAS TURNED BACKWORDS. I BROKE BOTH MAJOR BONES IN MY ARM DIRECTLY ABOVE MY WRIST. WHAT IS THE FORMULA OF THE FORCE AND WEIGHT HITTING THE FLOOR
A harmonic oscillator starts with an amplitude of 20.0 cm. After 10.0 s, the amplitude decreases to 15.0 cm. If the linear damping coefficient is 2.00 Ns/m, how much mass is oscillating
Answer: the amount of mass is oscillating is 34.8 kg
Explanation:
Given that;
amplitude A = 20.0 cm
time t = 10 s
amplitude decreases x = 15.0 cm
damping coefficient b = 2.00 N.s/m
amount of mass is oscillating = ?
we know that; amplitude can be expressed as;
x = Ae^-(∝t)
we substitute
15 = 20e^-∝(10)
∝ = 0.02877 s⁻¹
Hence mass m will be;
m = b/2∝
we substitute
m = (2 N.s/m) / ( 2 × 0.02877 s⁻¹)
m = 34.8 kg
Therefore the amount of mass is oscillating is 34.8 kg
What are earth crossing asteroids and how do we monitor them
Answer:
Earth-crossing asteroid, asteroid whose path around the Sun crosses Earth's orbit. Two groups of such asteroids—Aten and Apollo asteroids—are distinguished by the size of their orbits and how closely they approach the Sun.
Explanation:
On a part-time job, you are asked to bring a cylindrical iron rod of density 7800 kg/m^3 , length 92.4 cm and diameter 2.15 cm from a storage room to a machinist. Calculate the weight of the rod, w. Assume the free-fall acceleration is g =9.81m/s^2
Answer:
25.68 N
Explanation:
From the question given above, the following data were obtained:
Density of cylindrical rod = 7800 kg/m³
Length = 92.4 cm
Diameter = 2.15 cm
Acceleration due to gravity (g) = 9.8 m/s²
Weight of rod =?
Next, we shall determine the volume of the rod. This can be obtained as follow:
Height (h) = 92.4 cm
Diameter (d) = 2.15 cm
Pi (π) = 3.14
Volume (V) =?
V = π(d/2)²h
V = 3.14 × (2.15/2)² × 92.4
V = 335.29 cm³
Next, we shall convert 335.29 cm³ to m³. This can be obtained as follow:
1 cm³ = 1×10¯⁶ m³
Therefore,
335.29 cm³ = 335.29 cm³ × 1×10¯⁶ m³ / 1 cm³
335.29 cm³ = 0.00033529 m³
Thus, 335.29 cm³ is equivalent to 0.00033529 m³.
Next, we shall determine the mass of the rod. This can be obtained as follow:
Density of rod = 7800 kg/m³
Volume of rod = 0.00033529 m³.
Mass of rod =?
Density = mass /volume
7800 = mass / 0.00033529
Cross multiply
Mass of rod = 7800 × 0.00033529
Mass of rod = 2.62 Kg
Finally, we shall determine the weight of the rod. This can be obtained as follow:
Mass (m) of rod = 2.62 Kg
Acceleration due to gravity (g) = 9.8 m/s²
Weight (W) of rod =?
W = m × g
W = 2.62 × 9.8
W = 25.68 N
Therefore, the weight of the rod is 25.68 N
A 7750 kg space probe, moving nose-first toward Jupiter at 179 m/s relative to the Sun, fires its rocket engine, ejecting 72.0 kg of exhaust at a speed of 230 m/s relative to the space probe. What is the final velocity of the probe?
Answer:
179.47m/s
Explanation:
Using the law of conservation of momentum
m1u1 + m2u2 = (m1+m2)v
m1 and m2 are the masses
u1 and u2 are the initial velocities
v is the final velocity
Substitute
7750(179)+72(230) = (7750+72)v
1,387,250+16560 = 7822v
1,403,810 = 7822v
v = 1,403,810/7822
v= 179.47m/s
Hence the final velocity of the probe is 179.47m/s
PLEASE HELP!!! Which process in living things evolved as oxygen levels increased in Earth’s atmosphere?
glycolysis
photosynthesis
fermentation
aerobic respiration
Answer: Areobic Resporation
Explanation; -Aerobic respiration is the process in living things that evolved as oxygen levels increased in earth's atmosphere.
8
9
TIME REMAINING 10:34
Which statement describes an atomic nucleſus?
An atomic nucleus is negatively charged.
An atomic nucleus has no electrical charge.
An atomic nucleus consists of mostly empty space.
An atomic nucleus contains most of the atom's mass,
An atomic nucleus . . .
-- contains all of the atom's positive charge
-- contains almost all of the atom's mass
-- contains none of the atom's negative charge.
Answer:
An atomic nucleus . . .
-- contains all of the atom's positive charge
-- contains almost all of the atom's mass
-- contains none of the atom's negative charge.
Explanation:
yaaaaaa what the person on top said
g A proton and an alpha particle are released from rest at different locations from the negative plate of a charged parallel plate capacitor. The plates are 15 mm apart, and they are charged to a potential difference of 680 V. The alpha particle is placed at the point where the potential is 600 V. Where do you need to place the proton so that both particles reach the negative plate with the same speed
Answer:
d₂ = 6.18 mm
Explanation:
We can work on this interesting exercise using the concepts of energy conservation
alpha (1) particle, with have a charge q = 2e
Starting point
Em₀ = U = q V₁
final point
[tex]Em_{f}[/tex] = ½ m v²
Em₀ = Em_{f}
2eV₁ = ½ m₁ v²
v² =[tex]\frac{4 \ e \ V_{1}}{m_{1} }[/tex]
proton (2) particle, with have a charge q = e
Starting point
Em₀ = qV₂
Final point
Em_{f} = ½ m₂ v²
Em₀ = Em_{f}
eV₂ = ½ m₂ v²
v² = [tex]\frac{2 \ e \ V_{2} }{m_{2} }[/tex]
in the exercise, it should be noted that the two particles have the same velocity when reaching the plate, therefore let us solve the velocity in each equation and equal
\frac{4 \ e \ V_{1}}{m_{1} }= \frac{2 \ e \ V_{2} }{m_{2} }
[tex]V_{2} = \frac{2 m_{2} }{m_{1} } \ V_{1}[/tex]
the alpha particle is composed of two protons and two neutrons, therefore in first approximation
m₁ = 4 m₂
subtitute
V₂ =[tex]\frac{1}{2}[/tex] V₁
let's calculate
V₂ = [tex]\frac{1}{2}[/tex] 600
V₂ = 300 V
To find the distance we use the relationship between the electric field and the potential difference
V = -d E
The electric field between the plates is constant, so
E = - V / d = - V₂ / d₂
d₂ = [tex]\frac{V_{2} }{V} \ d[/tex]
let's calculate
d₂ = [tex]\frac{300}{680} \ 15[/tex]
d₂ = 6.18 mm
4. A box of old textbooks is on the middle shelf in the bookroom 1.3 m from the floor. If the janitor relocates the box to the shelf that is 2.6 m from the floor, how much work does he do on the box. The box has a mass of 10.0 kg.
Answer:
127.53 J
Explanation:
Given that
Height of the floor, h = 1.3 m
Acceleration due to gravity, g = 9.81 m/s²
Mass of the box, m = 10 kg
To find the work done on the box by the janitor, we use the formula for potential energy. Remember that potential energy is actually the energy stored in an object as a result of its position.
P.E = mgh, substituting each parameters for its value, we then have
P.E = 10 * 9.81 * 1.3
P.E = 127.53 J
Therefore, we can conclude that the amount of work done on the box by the janitor is 127.53 J
If vector A= aj^ and vector B = bj^, then vector A×B is equal to
Answer:
0 because j×j =0
Explanation:
so a×b is 0
A microscope using ultraviolet light is used to study bacteria. If the aperture diameter is 1.5 cm and it is desired to distinguish features with an angular size 0.036 arc seconds, what maximum wavelength can be used
Given :
A microscope using ultraviolet light is used to study bacteria. If the aperture diameter is 1.5 cm.
Angular size is 0.036 arc seconds.
To Find :
The maximum wavelength that can be used.
Solution :
Converting given angle into radians :
[tex]\theta = \dfrac{0.036}{3600}\times \dfrac{\pi}{180}\\\\\theta = 1.745\times 10^{-7}\ radians[/tex]
Now, we know maximum wavelength is given by :
[tex]\lambda = \dfrac{\theta \times D}{1.22}\\\\\lambda = \dfrac{1.745\times 10^{-7} \times 0.015}{1.22}\ m\\\\\lambda =2.145 \times 10^{-7}\ m[/tex]
Hence, this is the required solution.
Electrical equipment in an office takes a current of 13 A from a 240 V supply.
Estimate the cost per week of electricity if the equipment is used for 30 hours each
week and 1 kWh of energy costs Rm0.50
Answer:
The cost per week of electricity is Rm 46.8
Explanation:
Electrical Power and Energy
The electrical power consumed by an appliance connected to a voltage V and carrying a current I is given by:
P = V.I
The energy consumed by an electrical appliance of power P during a time t is:
E = P.t
The electrical equipment in an office takes I=13 A when connected to a V=240 V supply.
The power consumed is:
P = 240 V * 13 A
P = 3,120 Watt
Converting to Kilowatt:
P = 3,120/1,000 KW
P = 3,12 KW
If the equipment is used t=30 hours each week, the energy is:
E = 3.12 KW * 30 h
E = 93.6 KWh
Since the cost of each KWh is Rm 0.50, the weekly cost of electricity is:
C = 93.6 * 0.50 = 46.8
The cost per week of electricity is Rm 46.8
A rod is made of three segments of equal length with different masses. The total mass of the rod is 6m. Will the moment of inertia of the rod be (i) greater about the left end, (ii) greater about the right end, or (iii) the same about both ends
Answer: (iii) the same about both ends
Explanation:
The moment of inertia is the sum of the square of the distance from the axis of massage and rotation of each length of the rod. The moment of inertia can be expressed as I = imiri2. The connection of the rod is the product of the moment length and distance (square), so it is the same at both ends.
The moment of inertia depends on the distribution of mass and the square of the distance from the axis.
The moment of inertia of the rod is the same about both ends. Hence, option (iii) is correct.
What is the moment of inertia?The degree measure of the resistance of an object towards an angular acceleration about the given axis is known as the moment of inertia of an object.
Given data -
The total mass of rod is, M = 6m.
The moment of inertia is the sum of the square of the distance from the axis of massage and rotation of each length of the rod. The mathematical expression is given as,
[tex]I = M \times r^{2}[/tex]
Since the connection of the rod is the product of the moment length and distance (square), so it is the same at both ends.
Thus, we can conclude that the moment of inertia of the rod is the same about both the ends.
Learn more about the moment of inertia here:
https://brainly.com/question/6953943
What is albedo? What on Earth has high albedo?
Answer:
The fraction of incident light or radiation reflected by a surface or body, commonly expressed as a percentage.
2.
biology The whitish inner portion of the rind of citrus fruits that is a source of pectin, commonly referred to as the pith.
Explanation:
What type of simple machine is an electric fan?
Answer:
An electric fan is considered to be a mixture of several simple machines. It includes the Wheel and Axle type, wedges, and the Inclined plane types. The blades of an electric fan are the inclined planes and the wedges.
The distance between the object and its image formed by a plane mirror appears to be 24 cm. What is the distance between the mirror and the object?
Answer:
in a plane mirror distance of object from mirror is equal to distance of image
so it will be 24 ÷ 2 = 12 cm
which law of thermodynamics would be violated if heat were to spontaneously flow between two abject which are in thermal equilibrium?
Answer:
The law zero of thermodynamics.
Explanation:
The law zero of thermodynamics, which tells us that heat flows from a body at a higher temperature to another body with lower temperature, when the heat transfer is zero, it is said that the two bodies are in thermal equilibrium, their temperatures are equal
5. 3 women push a stalled car. Each woman pushes with a 400N force. What is the mass of the car if the car accelerates at 0.85 m/s??
Answer:
470.59 kgExplanation:
The the mass of the car can be found by using the formula
[tex]m = \frac{f}{a} \\ [/tex]
f is the force
a is the acceleration
From the question we have
[tex]m = \frac{400}{0.85} \\ = 470.58823...[/tex]
We have the final answer as
470.59 kgHope this helps you
Which statement describes the factors that affect the force of friction? Question 2 options: Friction is always the same no matter what Friction increases as the normal force (weight) increases, and also depends on the surface Friction is greater when objects are barely touching Friction is greater on slippery surfaces
Answer:
(b) Friction increases as the normal force (weight) increases, and also depends on the surface
Explanation:
The coefficient of friction relates the normal force between surfaces to the friction force opposing motion. The coefficient depends on the surface.
The appropriate choice is ...
Friction increases as the normal force (weight) increases, and also depends on the surface
it is difficult to smooth floor why
Complete question is:
It's is difficult to walk on a wet floor than a smooth floor. Why?
Answer:
Because friction on wet floor is far lesser than on a smooth floor
Explanation:
On wet surfaces, the friction is far lesser than on smooth surfaces and thus the grip between the bottom of your shoes/feet and the ground is very very small and as such walking on the wet surface becomes more difficult. Whereas on Smooth surfaces, there is plenty of friction and as a result, there is enough grip between the bottom of your shoes/feet and the ground thereby making walking far easier.
Which list ranks the three types of radiation from lowest penetrating power to
highest penetrating power?
A. Gamma < alpha < beta
B. Beta < alpha < gamma
C. Alpha < beta < gamma
D. Gamma < beta < alpha
Answer:gamma>beta>alpha
Explanation: Just took the test