Answer:
Explanation:
PE = mgh where m is the mass of the object, g is the gravitational pull on the object (always 9.8!), and h is the height of the object in meters.
PE = 25(9.8)(25) so
PE = 6125 J, choice C.
When a star like our sun runs out of nuclear fuel, it collapses to a white dwarf star the size of the Earth, but with the same mass the star had before the collapse. If a star initially rotates once every 25 days, like our sun, what will its rotation rate be after it becomes a dwarf
Answer:
T = 1.8 10² s
Explanation:
This is an exercise of conservation of angular momentum,
Initial instant. Before collapsing
L₀ = I₀ w₀
Final moment. After the collapse
L_f = I w
as the system is isolated, the moment is conserved
L₀ = L_f
I₀ w₀ = I w
w = [tex]\frac{I_o}{I} \ w_o[/tex]
indicates that the rotation period is 25 day, let's reduce to the SI system
T = 25 day (24 h / 1 day) (3600 s / 1 h) = 2.16 10⁶ s
Angular velocity and period are related
w = 2π/ T
The moment of inertia of a sphere is
I = 2/5 M R ²
in this case the moment before and after the collapse is
I₀ = 2/5 M R₀²
I = 2.5 M R²
the radius of a star like the sun is
R₀ = 6.96 10⁸ m
the radius of the earth
R = 6.371 10⁶ m
we substitute
w = [tex]\frac{I_o}{I} \ w_o[/tex]
[tex]\frac{2\pi }{T} =( \frac{R_o}{R} )^2 \ \frac{2\pi }{T_o}[/tex]
T = ([tex]\frac{R}{R_o}[/tex] )² T₀
let's calculate
T = (6.371 10⁶ / 6.96 10⁸ )² 2.16 10⁶
T = 1.8 10² s
When 685 J of thermal energy (heat) is added to 7.9 g of a substance at 31°C, the temperature increases from 31 °C to 98 °C. What is the specific heat of the substance?
Answer:
Specific heat capacity, = 1.2942 J/g°C
Explanation:
Given the following data;
Heat capacity = 685 J
Mass = 7.9 g
Initial temperature = 31°C
Final temperature = 98°C
To find the specific heat capacity of the substance;
Heat capacity is given by the formula;
[tex] Q = mcdt[/tex]
Where;
Q represents the heat capacity or quantity of heat.
m represents the mass of an object.
c represents the specific heat capacity of water.
dt represents the change in temperature.
dt = T2 - T1
dt = 98 - 31
dt = 67°C
Making c the subject of formula, we have;
[tex] c = \frac {Q}{mdt} [/tex]
Substituting into the equation, we have;
[tex] c = \frac {685}{7.9*67} [/tex]
[tex] c = \frac {685}{529.3} [/tex]
Specific heat capacity, = 1.2942 J/g°C
I need help?? Plz help me
Answer:
12. b
13. a
Explanation:
An ocean wave has a frequency of 9 Hz and a speed of 18 m/s. What is the wavelength of this wave?
O 162 m
O 0.5 m
02 m
0 27 m
Answer:
The answer is 2 because the formula is
wavelength=speed/frequency
How much (in newtons) does a 15-kg bag of feathers weigh? Show work
Here's the solution :
we know,
[tex] \boxed{weight = m \times g}[/tex]
where,
m = mass of the objectg = acceleration due to gravityso,
[tex]w = 15 \times 9.8[/tex][tex]w = 147 \: \: \: newtons[/tex]Electrons move towards the ________ end.
O negative
O positive
O front
O back
Answer:
they move towards the positive side... that's option 2
When responding to sound, the human eardrum vibrates about its equilibrium position. Suppose an eardrum is vibrating with an amplitude of 7.2 x10-7 m and a maximum speed of 3.6 x10-3 m/s. (a) What is the frequency (in Hz) of the eardrum's vibrations
Answer:
796.18 Hz
Explanation:
Applying,
Maximum velocity = Amplitude×Angular velocity
Therefore,
V' = A(2πf)............... Equation 1
Where V' = maximum velocity of the eardrum, A = Amplitude of vibration of the eardrum, f = frequency of the eardrum vibration, π = pie
make f the subject of the equation
f = V'/2πA................ Equation 2
From the question,
Given: V' = 3.6×10⁻³ m/s, A' = 7.2×10⁻⁷ m,
Constant: 3.14.
Substitute these values into equation 2
f = 3.6×10⁻³/( 7.2×10⁻⁷×2×3.14)
f = 796.18 Hz
why is it not possible to make use of solar cells to meet all of our energy needs?why
Answer:
In the solar cells, the energy is obtained only during the day, when the Sun shines. .So, it increases the cost of using solar panels as the source of energy. So, the solar cell is not used to meet all our energy needs
hope this helps
have a good day :)
Explanation:
Answer:
In the solar cells, the energy is obtained only during the day, when the Sun shines. ... So, it increases the cost of using solar panels as the source of energy. So, the solar cell is not used to meet all our energy needs
Explanation:
n the solar cells, the solar panel convert solar energy into electricity, which is stored in storage battery. The storage battery give the direct current but all the appliances are working by the alternating current, so first of all direct current is converted into alternating current by any suitable appliances before it can be used to run various devices. So it increases the cost of using solar panels as the source of energy.
A small cork with an excess charge of +6.0 µC is placed 0.95 m from another cork, which carries a charge of -4.3 µC. What is the magnitude of the electric force between them?
Answer:
F = 0.257 N
Explanation:
The magnitude of the electric force between the charges can be calculated by using Colomb's Law:
[tex]F = \frac{kq_1q_2}{r^2}[/tex]
where,
F = Electric Force = ?
k = Colomb's Constant = 9 x 10⁹ Nm²/C²
q₁ = charge on first cork = 6 μC = 6 x 10⁻⁶ C
q₂ = charge on second cork = 4.3 μC = 4.3 x 10⁻⁶ C
r = distance between corks = 0.95 m
Therefore,
[tex]F = \frac{(9\ x\ 10^9\ N.m^2/C^2)(6\ x\ 10^{-6}\ C)(4.3\ x\ ^{-6}\ C)}{(0.95\ m)^2}[/tex]
F = 0.257 N
What’s the mathematical relation between them
:the small mass and the larger mass.
Giving brainlist on this one
I really need help on this one please I’ll be so grateful!
Explanation:
there is no relationship between small mass and the bigger mass, but it can be related with the acceleration. Since Force is constant, acceleration is inversely proportional to the mass. Greater the mass, lesser is the acceleration and vise versa
16. A student uses 110 N of force to push a box
across a flat room for 7.2 m. Calculate the
amount of work that the student does. Round
your answer to two decimals and show the
correct units of measure.
Answer:
792J
Explanation:
Use the formula Force × Distance
With 110 newtons being the force and 7.2 meters being the distance
Which gives 792 and work us measured in joules therefore its joules
Work done is the dot product of force and displacement. The work done on the box to push across the surface for 7.2 m by applying a force of 110 N is 792 J.
What is force?Force is an external agent acting on a body tp change it from the state of motion or rest. Force is a vector quantity thus, it is characterized by a magnitude and direction.
When force acting on a body results in displacement of the body, it is said to be work done on the body. The work done on the body is the product of force and displacement.
W = F d.
Given the force acting on the box = 110 N
displacement d = 7.2 m
Work done w = 110 N × 7.2 m
= 792 J.
Therefore, the work done on the box is 792 J.
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A boat produces a wave as it passes an aluminum can floating in a lake. Explain why the can merely moves up and down while waves propagate away from the disturbance caused by the boat.
Answer:
Due to waves.
Explanation:
The can merely moves up and down because the movement of the waves that propagate away from the disturbance caused by the boat. The Can has low density due to low mass and high volume which allow the can to float on the surface of water after prevent it from the drowning. The wave moves the can up and down but prevent it from going deep inside the water so we can say that the can moves due to movement of waves in water.
A student is constructing an investigation on static electricity. The student has three balloons and rubs two of them on a piece of wool. The student then touches each balloon to the wall to observe if static electricity would cause the balloon to stick. What is the independent variable in this investigation.
Answer:
Explanation:
As given, the student has three balloons and rubs two of them on a piece of wool. The rubbing of balloon on wool is the independent variable as it was done on two and not on the third as control.
he amount of energy required to break a nucleus into individual protons and neutrons is called
It would be C: Binding Energy
I put the screenshot below.
Answer:
1-a
2-d
3-c
4-b
Explanation:
i tookt he words and put it in the sentance and these made most sence to me
Which statement best explains why there could be a force of attraction
between two electrically charged objects?'
because they have like charges
because they have unlike charges
because they have the same number of protons
because they have the same number of electrons
The figure below shows the apparatus used to measure the specific heat capacity of a metal. The electric heater is switched on and supplies 17 000 of thermal energy (heat) to the block of metal. The temperature of the metal rises from 16 °C to 38 °C. The mass of the block of metal is 850 g. No energy is lost from the metal. Calculate the specific heat capacity of the metal.
Answer:
0.909 J/gºC.
Explanation:
From the question given above, the following data were obtained:
Heat (Q) = 17000 J
Initial temperature (T₁) = 16 °C
Final temperature (T₂) = 38 °C
Mass (M) = 850 g
Specific heat capacity (C) =?
Next, we shall determine the change in the temperature of the metal. This can be obtained as follow:
Initial temperature (T₁) = 16 °C
Final temperature (T₂) = 38 °C
Change in temperature (ΔT)
ΔT = T₂ – T₁
ΔT = 38 – 16
ΔT = 22 °C
Finally, we shall determine the specific heat capacity of the metal. This can be obtained as follow:
Heat (Q) = 17000 J
Change in temperature (ΔT) = 22 °C
Mass (M) = 850 g
Specific heat capacity (C) =?
Q = MCΔT
17000 = 850 × C × 22
17000 = 18700 × C
Divide both side by 18700
C = 17000 / 18700
C = 0.909 J/gºC
Therefore, the specific heat capacity of the metal is 0.909 J/gºC.
Make a free-body diagram of someone pushing a refrigerator that shows:
a. A net force of 100 N with the refrigerator being pushed to the right.
b. The refrigerator is balanced on the floor.
The free body diagram allows to find the results for the forces applied on the refrigerator are;
a) Free-body diagram with applied force.
b) Free-body diagram without applied force.
A free-body diagram is a diagram of the forces without the details of the body, these diagrams are important to clearly visualize the forces and the coordinate systems against which to take measurements.
In the attached we have a free-body diagrams for a refirerator, represented by the box where the forces are appreciated:
The weight that the forces exerted by the earth on the refrigerator. The Normal which is the reaction of the earth to the support of the refrigerator. The force applied by the person. The friction force which is the force between the two surfaces that opposes the movement of the refrigerator.
Newton's second law states that the net force is proportional to the mass times the acceleration of the body.
∑ F = ma
where F is the force, m the mass and the acceleration
∑ F = F - fr = 100 N
a = 100 / m
In conclusion with the free body diagram we can find the results for the forces applied on the refrigerator are;
a) Free-body diagram with applied force.
b) Free-body diagram without applied force.
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In a plate glass factory, sheets of glass move along a conveyor belt at a speed of 15.3 cm/s. An automatic cutting tool descends at preset intervals to cut the glass to size. Since the assembly belt must keep moving at constant speed, the cutter is set to cut at an angle to compensate for the motion of the glass. The glass is 73.4 cm wide and the cutter moves from one edge to the other in 3.0 s. At what angle to the width of the sheet should the cutter be set to move?
n a plate glass factory, sheets of glass move along a conveyor belt at a speed of 15.3 cm/s. An automatic cutting tool descends at preset intervals to cut the glass to size. Since the assembly belt must keep moving at constant speed, the cutter is set to cut at an angle to compensate for the motion of the glass. The glass is 73.4 cm wide and the cutter moves from one edge to the other in 3.0 s. At what angle to the width of the sheet should the cutter be set to move
Pls help me...
..............
Explanation:
The graphs show maximum gravitational potential energy for the pendulum and they correspond to positions #1 and #5.
i’ll give brainliest!! please help and answer correctly! plsss answer quick
Answer:
i dont think anything will happen so maybe A: the wall is larger than you.
Explanation:
2.) A red star is 55 solar radii and a white star is 52 solar radii. Which star will 1 point
appear brighter in the night sky?*
Answer:white star
Explanation:
the efficiency of a machine is always less than 100% because part of the energy input is used to
A. stop the machine after work
B. perform useful work on the load
C. overcome friction
D. lift the machine up
Answer:
C. Overcome Friction
Explanation:
When using any machine usually those with moving parts, you may notice heat forming near the areas where most movement occurs. As friction continues, more energy is used up and released as heat. For that reason, the efficiency of a machine will forever be less than 100%
A Star fleet science officer drops a large rock from a height of 1.55 m onto the surface of an alien planet. The rock strikes the ground in 0.230 s. Determine the acceleration of gravity.
Answer:
58.6 m/s²
Explanation:
Applying,
s = ut+gt²/2............ equation 1
Where s = height of the rock, u = initial velocity, t = time, g = accelration due to gravity of the planet.
From the question,
Given: s = 1.55 m, t = 0.23 s, u = 0 m/s (dropped from an height)
Substitute these values into equation 1
1.55 = (0×0.23)+g(0.23²)/2
1.55 = 0.0529g/2
0.0529g = 3.1
g = 3.1/0.0529
g = 58.6 m/s²
In the diagram, R1 = 40.0 ,
R2 = 25.4 Q, and R3 = 70.8 Q. What is
the equivalent resistance of the group?
Reg = [ ? ]
(And none of those links please)
Answer:
51 Ω.
Explanation:
We'll begin by calculating the equivalent resistance of R₁ and R₃. This can be obtained as follow:
Resistor 1 (R₁) = 40 Ω
Resistor 3 (R₃) = 70.8 Ω
Equivalent Resistance of R₁ and R₃ (R₁ₙ₃) =?
Since the two resistors are in parallel connection, their equivalent can be obtained as follow:
R₁ₙ₃ = R₁ × R₃ / R₁ + R₃
R₁ₙ₃ = 40 × 70.8 / 40 + 70.8
R₁ₙ₃ = 2832 / 110.8
R₁ₙ₃ = 25.6 Ω
Finally, we shall determine the equivalent resistance of the group. This can be obtained as follow:
Equivalent Resistance of R₁ and R₃ (R₁ₙ₃) = 25.6 Ω
Resistor 2 (R₂) = 25.4 Ω
Equivalent Resistance (Rₑq) =?
Rₑq = R₁ₙ₃ + R₂ (series connection)
Rₑq = 25.6 + 25.4
Rₑq = 51 Ω
Therefore, the equivalent resistance of the group is 51 Ω.
All of the following are phases of
memory, with the exception of
which?
A. encoding
B. storage
C. timing
D. decoding
We have that the exception from the Memory phase is
Timing
From the question we are given
A. encoding
B. storage
C. timing
D. decoding
Generally
EncodingThis can be defined as memory phase where memory is storage , the the data to be stored is embedded on the storage device StorageThis Speak to the aspect of Securing for a long time a stored data. TimingTiming on the other hand is not a storage PhaseDecodingDecoding Speaks of the accept of memory where date stored id disbursed for use .Therefore
The the exception from the Memory phase is Timing
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how does energy apply to newton’s laws?
Answer:
the acceleration of an object is directly pro to the net force acting on it and indirectingly proportional to its mass
Two particles experience an attractive electric force of 5 N. If one of the charges triples and
the distance between them doubles, what is the new electric force?
3.75 N
Explanation:
F = k(q)(q)/r^2 = 5 N
F' = k(q)(3q)/(2r)^2
= k×3(q)(q)/4r^2
= (3/4)[k(q)(q)/r^2]
= (3/4)F
= (3/4)(5 N)
= 3.75 N
The new electric force is 3.75 N.
The force on the charges by Coulomb's law is given by;
F = kq1q2/r^2
where q1=q2
F = kq1^2/r^2
Where F = 5N
If one of the charges triples;
q2 = 3q1
distance doubles = r = 2r
F' = 3kq1^2/4r^2
So;
F' = 3/4 F
F' = 3/4 × 5 = 3.75 N
The new electric force is 3.75 N.
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It takes a crane 60 seconds to lift a 150kg box from the ground to the top of a 100m tall building. Calculate the magnitude of power exerted by the crane to lift the box
A. 9 x 109 W
B. 9 x 109 N
C. 2450 W
D. 2450 N
E. None of the above
Answer:
Explanation:
Power equals the amount of work done divided by the time it takes to do the work (in seconds). Work itself is equal to the amount of force it takes to move an object a certain number of meters. We are given the mass of the object. Since force is a measure in Newtons, and we are given mass, we need to use the mass to find the weight of the object, since weight is a force and is measured in Newtons!
F = weight = 150(9.8) so
F = 1470. Now we will use that along with the displacement in the Power equation:
P = [1470(100)]/60 so
P = 2450 Watts, choice C.
A teacher is performing a demonstration about static electricity for his class by rubbing a balloon against a wool sweater. The balloon sticks to the wool sweater. Which particles are exchanged during the demonstration
Explanation:
the balloons which is positive looses an electron to the sweater, and the sweater which is negative gains the electron
Static charge is developed within a body temporarily with an induced polarization. Electrons are exchanged from wool surface to the balloon when they rubbed against each other.
What is static electricity?When two materials rub against each other in which one to be an insulator, they will attract by the induced polarization. Rubbing causes the free electrons in the condutor to be transferred towards the insulator.
This will cause a deformation that, the random charges in the material get polarized where the electrons in the insulator will repel to the opposite pol and positive charges will align in a pole close to the condutor.
This charge separation causes the positive pole of the balloon gets attracted into the wool surface. Hence, there forms a static electricity by the passage of electron. Thus free electrons are the particles exchanged in the demonstration.
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