Answer:
A. 80 N
Explanation:
Since the uniform plank is pivoted at its center at an angle of 30 to the vertical, then it is 90° - 30° = 60° to the horizontal.
Let L be the length of the plank = 4 m, the perpendicular distance of the 4 kg mass form the pivot point is Lcos60°/2. Then the moment of the 4 kg mass about its pivot point is mgLcos60/2 where m = mass = 4 kg and g = acceleration due to gravity = 10 m/s²
Let F be the force applied at 0.5 m from the pivot point. The perpendicular distance of F from the pivot point is 0.5cos60°. Thus the moment of this force about the pivot point is F × 0.5cos60° = 0.5Fcos60°
Since both moments are the same for equilibrium,
mgLcos60/2 = 0.5Fcos60°
F = mgL/(2 × 0.5 m)
F = 4 kg × 10 m/s² × 4 m/1 m
F = 80 kgm/s²
F = 80 N
What are the si units
Answer:
The uniy which is accepted all over the world is called SI unit.
Explanation:
The system of measurement that is agreed by the international convention if scientists that is held in paris of France to adopt an international unit is called SI unit unit.
pls answer my quetion i will give brainlist answer
Answer:
here's an explanation but not the answer
please kindly send No or Yes understand.
Explanation:
A 10-N force is applied to push a block across a friction free surface for a displacement of 5.0 m to the right.
See Answer
See Answer
A 10-N frictional force slows a moving block to a stop after a displacement of 5.0 m to the right.
Two arrows are shot vertically upward. The second arrow is shot after the first one, but while the first is still on its way up. the initial speeds are such that both arrows reach their maximum heights at the same instant, although these heights are different. Suppose the that initial speed of the first arrow is 34 m/s and that the second arrow is fired 0.204081632653061 seconds after the first. Determine the initial speed of the second arrow.
Answer:
The initial speed of the second arrow is 33.8 m/s.
Explanation:
initial speed of first arrow, u = 34 m/s
Let the initial height of the second arrow is h.
Let they both reaches at maximum height H.
Let the time taken by the first arrow is t and the second arrow is t - 0.0204
Let the initial speed of the second arrow is u'.
Use first equation of motion for the first arrow.
v = u - gt
0 = u - gt
34 = gt ..... (1)
For the second arrow
v =u' - g (t - 0.0204)
0 = u' - gt + 9.8 x 0.0204
u' = 34 - 0.1999 = 33.8 m/s
Which of the following best describes the formation of surf? Waves energy, rebounding from its impact with shore, crashes into oncoming waves, causing them to break. Entering shallow water forces wave energy upward, making the wave crest unstable and causing it to break. A wave encountering shallow water begins to slow at its bottom, while the top of the wave continues at its previous speed. This causes the wave to break. As waves enter shallow water, the distance between wave crests (wave length) shortens, increasing the tendency to break.
Answer:
The question above would be written again but this time with options attached to it for comprehension sake:
Which of the following best describes the formation of surf?
A. Waves energy, rebounding from its impact with shore, crashes into oncoming waves, causing them to break.
B. Entering shallow water forces wave energy upward, making the wave crest unstable and causing it to break.
C. A wave encountering shallow water begins to slow at its bottom, while the top of the wave continues at its previous speed. This causes the wave to break.
D. As waves enter shallow water, the distance between wave crests (wavelength) shortens, increasing the tendency to break.
The correct answer is option C (A wave encountering shallow water begins to slow at its bottom, while the top of the wave continues at its previous speed. This causes the wave to break).
Explanation:
Surf could mean crashing waves or breaking waves. Generally, the wave speed is constant in the same medium, however, the wave speed decreases as it enters shallow water which is largely due to the water depth which is relatively small, especially when it encounters the bottom of the shallow water. While the top of the wave overtakes the bottom of the wave, making sure the top of the wave continues at its previous speed.
La resistividad de cierto alambre es 1.72x10 -8 Ωm a 20 oC .Una batería de 6v se conecta a una bobina de 20 m de este alambre, con un diámetro de 0.8 mm. ¿Cuál es la corriente en el alambre?
Answer:
i = 1.09 10⁴ A
Explanation:
For this exercise we will look for the resistance of the wire
R = ρ L / a
the area of the wire is
a =ππ r² = π πd² / 4
we substitute
R = ρ L 4 / π d²
R = 1.72 10⁻⁸ 20 4/π 8 10⁻⁴
R = 5.47 10⁻⁴ Ω
to calculate the current we use ohm's law
V = R i
i = V / R
i = 6 / 5.47 10⁻⁴
i = 1.09 10⁴ A
What is the magnification when an object is placed at 2f from the pole of the convex mirror?
-2/ 3
-3/2
-1
-1/3
Answer:
Linear magnification = 1/3
Explanation:
Given:
Convex mirror
Object's distance from pole = 2f
Find:
Linear magnification
Computation:
Object distance, u = −2f
So,
1/v + 1/u = 1/f
1/v + 1/(-2f) = 1/f
1/v = 1/f + 1/2f
BY taking LCM
1/v = 3 / 2f
v = 2f / 3
Magnification, M = -v / u
So,
Magnification, M = (2f / 3) / 2f
Magnification, M = 2f / 6f
Magnification, M = 2 / 6
Linear magnification = 1/3
8× +5+9×+3 how can I solve this
Answer:
collect like terms then add=>8x+9x+5+3
=>8x+9x+5+3=>17x+8
Which type of electromagnetic radiation is responsible for the colors of
objects?
O A. Radio waves
O B. X-rays
O C. Visible light
O D. Ultraviolet radiation
Answer:
C. Visible light
Explanation:
Visible light is responsible for the colors of objects.
Hope it will help :)❤
Una lámpara requiere 5 A y presenta una resistencia de 20 Ω, cuando está
encendida.
a. ¿Cuál es la tensión?
b. ¿Qué resistencia adicional requiere si se desea operar a 120 V?
c. ¿Y 110 V?
Answer:
a. V = 100 voltios
b. Para 120 V → [tex]R_{2} = 4 \Omega[/tex]
c. Para 110 V → [tex]R_{2} = 2 \Omega[/tex]
Explanation:
a. La tensión se puede calcular mediante la ley de Ohm:
[tex] V = IR [/tex]
V: es el voltaje o tensión =?
I: es la corriente = 5 A
R: es la resistencia = 20 Ω
Entonces, la tensión es:
[tex]V = IR = 5 A*20 \Omega = 100 V[/tex]
b. La resistencia adicional es la siguiente:
[tex] R_{2} + R_{1} = \frac{V}{I} [/tex]
[tex]R_{2} = \frac{V}{I} - R_{1} = \frac{120 V}{5 A} - 20 \Omega = 4 \Omega[/tex]
c. La resistencia adicional para operar a 110 voltios es:
[tex]R_{2} = \frac{V}{I} - R_{1} = \frac{110 V}{5 A} - 20 \Omega = 2 \Omega[/tex]
Espero que te sea de utilidad!
which way would 2 negatively charged balloons naturally move? what would that do to the amount of potential energy stored in the field?
Answer:
gsg
Explanation:
The balloons with negative charges moves apart from each other by electrostatic force of repulsion. The potential energy in them increases as they move away.
What is force of repulsion?The basic principle of charges is that, two like charges repel and unlike charge attracts. That is: two negative charged bodies or two positively charged bodies will repel each other and one negative charged body attracts a positively charged body.
In both cases attraction or repulsion the charged particles exerts a force with each other called the electrostatic force. The electrostatic force between two charges is directly proportional to the magnitude of charges and inversely proportional to the distance between them.
The balloons with negative charges moves apart from each other by electrostatic force of repulsion. The potential energy in them increases as they move away.
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what is the size of the electron charge?
Answer:
It’s like medium uk
Explanation:
The size of electron charge is estimated to be 1.6 × 10-¹⁹
How many types of galaxies are there?
a. 3
b. 4
c. 5
d. 6
Determine the amount of work done by the applied force when a 87 N force is applied to move a 15 kg object a horizontal
distance of 4.5 meters at a constant speed.
Answer:
391.5 J
Explanation:
The amount of work done can be calculated using the formula:
W = F║d where the force is parallel to the displacementLooking at the formula, we can see that the mass of the object does not affect the work done on it.
Substitute the force applied and the displacement of the object into the equation.
W = (87 N)(4.5 m) W = 391.5 JThe amount of work done on the object is 391.5 J in order to move it 4.5 meters with an applied force of 87 Newtons.
Mass doesn't matter on amount of work done .We can calculate amount of work done through Force and Displacement
Force=87NDisplacement=4.5m[tex]\boxed{\sf W=Fd}[/tex]
W denotes to work doneF denotes to forced denotes to displacement[tex]\\ \sf\longmapsto Work\:Done=87(4.5)[/tex]
[tex]\\ \sf\longmapsto Work\:done=391.5J[/tex]
Which of the following changes occurs during nuclear fission?
A. Energy is absorbed from the surroundings.
B. Atomic nuclei combine to form a larger nucleus.
C. Energy is converted into mass.
D.
The parent nucleus splits into lighter daughter elements.
Reset
Answer:
The parent nucleus splits into lighter daughter elements
Explanation:
Nuclear fission involves the splitting of nucleus of a lighter element with smaller particles
(give the answer or I'll report) please solve it with the steps
Answer:
The required elastic potential energy is 0.068J
Explanation:
Given,
Spring force constant, k= 3.4 N/M
Spring stretch length/ Displacement, x= 0.2m
We know,
Elastic potential energy, V= [tex]\frac{1}{2} kx^{2}[/tex]
=[tex]\frac{1}{2}*3.4*(0.2)^{2}[/tex]
=[tex]\frac{0.136}{2}[/tex]
=0.068
∴The required elastic potential energy is 0.068J
Iron meteorites are interpreted as deriving from the cooled metallic core of a largeish asteroid. This is based upon:
Answer:
This is based upon the fact that meteorites are generally believed to have originated as solid debris from Larger bodies like meteoroid or asteroids
Explanation:
Iron meteorites are interpreted as deriving from the cooled metallic core of a larger asteroid , because meteorites are generally believed to have originated as solid debris from Larger bodies like meteoroid or asteroids that are located outside the planet but found their way into our planet .
A piston is resting halfway into a cylinder containing gas in thermal equilibrium. The layer of molecules next to the closed end of the cylinder is suddenly flash-heated to a very high temperature. Which best describes what happens next
Answer: hello the options related to your question is missing attached below are the missing options
answer : The molecules with the highest temperature will bounce off their neighbors, losing energy to them and so on until the system is at a new equilibrium with the piston moved out ( option B )
Explanation:
What best describes the situation of what will happen next as explained in the question is in Option B
Because molecules with higher temperatures will always posses higher kinetic energy and they will collide more frequently with surrounding molecules passing on their energy in the process until the energy gets to the molecules closest to the piston. The molecules closest to the piston will then hit the piston until a new equilibrium is achieved
Sounds are made when objects ____ in air. What one word completes the sentence?
If anybody could help me it would be nice :) <333
Answer:
are crashing?
hope it's good hahah.
The correct answer is: "vibrate".
To find the correct word to complete the sentence, we need to know more about the sound wave.
What is sound wave?
Sound wave is a longitudinal wave i.e. the particles vibrate along the direction of propagation of wave.It requires a material medium to travel i.e. it can not travel in vacuum.How does sound wave produce?
Sound wave is produced due to variation of pressure in a medium. The high pressure region is compression region and low pressure region is rarefaction region.In case of an object, these pressure variations are produced by its vibration in a medium.Thus, we can conclude that sounds are made when objects vibrate in air.
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I will mark you as brainliest
pls ans
a) Name the graph?
b) In first 2 s the object is said to be in ______________ motion.
(uniform motion / uniform acceleration)
c) The portion BC of the graph represents which type of motion?
d) Find out acceleration in first 2 s?
I don't know♀ what is your favorite song
Given the following reactants, what are the most likely products?
In which stage of a star's life cycle, does gravity and fusion become balanced, and an adult star forms?
A. Main-sequence
B. Red supergiant
C. Protostar
D. White dwarf
Answer:
im guessing red giant-
A (200 g) of water at (80 °C) is mixed with (100 g)of water at (20 °C). What is the final temperature of the water?
Answer:
60 °C
Explanation:
From the question given above, the following data were obtained:
Mass of 1st sample (M₁) = 200 g
Temperature of 1st sample (T₁) = 80 °C
Mass of 2nd sample (M₂) = 100 g
Temperature of 2nd sample (T₂) = 20 °C
Equilibrium temperature (Tₑ) =?
NOTE: Since the sample are the same, the specific heat capacity is constant.
We can obtain the equilibrium temperature as follow:
Heat lost by 1st = heat gained by the 2nd
M₁C(T₁ – Tₑ) = M₂C(Tₑ – T₂)
Cancel out C
M₁(T₁ – Tₑ) = M₂(Tₑ – T₂)
200 (80 – Tₑ) = 100 (Tₑ – 20)
Clear bracket
16000 – 200Tₑ = 100Tₑ – 2000
Collect like terms
16000 + 2000 = 100Tₑ + 200Tₑ
18000 = 300Tₑ
Divide both side by 300
Tₑ = 18000 / 300
Tₑ = 60 °C
Therefore, the equilibrium temperature (i.e the final temperature) of the mixture is 60 °C.
If you were capable of converting mass to energy with 100%, efficiency, how much mass would you need to produce 3.5x10^12 Joules of energy?
Answer:
a) 3.9 x 10⁻⁵ kg
Explanation:
The amount of mass required to produce the energy can be given by Einstein's formula:
[tex]E = mc^2\\\\m = \frac{E}{c^2}[/tex]
where,
m = mass required = ?
E = Energy produced = 3.5 x 10¹² J
c = speed of light = 3 x 10⁸ m/s
Therefore,
[tex]m = \frac{3.5\ x\ 10^{12}\ J}{(3\ x\ 10^8\ m/s)^2} \\\\m = 3.9\ x\ 10^{-5}\ kg[/tex]
Hence, the correct option is:
a) 3.9 x 10⁻⁵ kg
A train traveled 100 kilometers north in 2 hours. After exchanging some railroad cars, it traveled 100 kilometers south in 2 hours along the same track. Why has the train's velocity changed
Answer:Due to change in direction
Explanation:
Given
Initially train has traveled a 100 km in North and after exchanging some railroad cars, it traveled 100 in south.
The velocity of the train changes as it direction of motion changes. Velocity is the vector quantity which require direction and magnitude for its reperesentation.
the volume and the mass of substance are 15cm3 and 27 gm respectively find its density
Answer:
[tex]d=1.8\ g/cm^3[/tex]
Explanation:
Given that,
Mass, m = 27 grams
Volume of the substance, V = 15 cm³
We need to find the density of the substance. We know that, the density of an object is given by mass per unit volume. So,
[tex]d=\dfrac{m}{V}\\\\d=\dfrac{27}{15}\\\\d=1.8\ g/cm^3[/tex]
So, the density of the substance is equal to [tex]1.8\ g/cm^3[/tex].
True or false
scientific research has now proven that atoms are composed of parts that are larger than protons neutrons and electrons
Answer:
False
Explanation:
parts that are smaller than protons neutrons and electrons
f the voltage in a circuit is 80 volts and the resistance is 20 ohms, what is the current?
I = 4 A
Explanation:
From Ohm's law, the voltage is given by
V = IR
or
I = V/R = (80 V)/(20 ohms)
= 4 A
A 60-W light bulb runs on 120 V and draws 0.50 A of current when running
for 10 minutes (600 seconds). How much energy does the light bulb use up
this time?
Answer:
3600 J
Explanation:
According to given question
P(rated)=60w
V= 120
I =0.50 A
t=600 second
Now,
Energy can be calculated as :
[tex]E= VI*t[/tex]
Where,
V is voltage
I is current
t is time in second
Now,
Putting the all value in above equation E
So,
[tex]E=120*0.5*600\\E=36000 J[/tex]
Therefore, 36000 J energy use up by light bulb
A children's roller coaster is released from the top of a track. If its maximum speed at ground level is 3 m/s, find the height it was released from.
Answer:
h = 0.46 m
Explanation:
According to the law of conservation of energy:
Potential Energy Lost by Roller Coaster = Kinetic Energy Gained by Roller Coaster
[tex]mgh = \frac{1}{2}mv^2\\\\2gh = v^2\\\\h = \frac{v^2}{2g}[/tex]
where,
h = height = ?
v = speed at bottom = 3 m/s
g = acceleration due to gravity = 9.81 m/s²
Therefore,
[tex]h = \frac{(3\ m/s)^2}{(2)(9.81\ m/s^2)}[/tex]
h = 0.46 m
An object of mass m slides down an incline with angle 0.
Which expression
shows the net force on the object along the surface of the incline?
A. mg cos(0) - FN
B. mg cos(0)
C. mg sin(0)
D. mg sin(0) - FN
Answer:
C. mg sin(θ)
Explanation:
The plane is incline and the only force acting in the object is the gravity, so you multiply mg per sin(θ) because sin(θ) gave you the part of the gravity acting in the horizontal direction parallel with the inclined surface
The expression shows the net force on the object along the surface of the incline is mg sin(θ). The correct option is C.
What is Net force?When two or more forces are acting on the system of objects, then the to attain equilibrium, net force must be zero.
An object of mass m slides down an incline with angle (θ).
The plane is incline and the only force acting in the object is the gravity, The weight or gravity acting in the horizontal direction parallel with the inclined surface is mg sin(θ).
Thus, the correct option is C.
Learn more about net force.
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