Answer:
The focal length of the lens is +30 and it is a convex lens.
Explanation:
Given that,
The nearest distance of distinct vision of a hypermetropial person is 60 cm, v = -60 cm
The distance is reduced by 20 cm, u = -20 cm
We need to find the nature and focal length of the lens.
Let f be the focal length of the lens. Using lens formula,
[tex]\dfrac{1}{v}-\dfrac{1}{u}=\dfrac{1}{f}\\\\\dfrac{1}{f}=\dfrac{1}{(-60)}-\dfrac{1}{(-20)}\\\\f=+30\ cm[/tex]
So, the focal length of the lens is +30 and it is a convex lens.
In one cycle of any heat engine
A. the net work done is larger than the heat exhausted.
B. more heat flows from the engine than enters the engine.
C. The internal energy of the engine does not change.
D. the net heat flow is zero.
Answer:
D. the net heat flow is zero
Explanation:
In one cycle of any heat engine, three things happen:
Heat is added; this causes high temperature in the engine ([tex]Q_H[/tex])Some of the energy from that input heat is used to perform work (W). The rest of the heat is removed at a relatively cold temperature ([tex]Q_C[/tex]).[tex]Q_H = W + Q_C[/tex]
Conclusively, the net heat flow is zero
The net force experienced by an object is increased. What affect does this have on the acceleration of the object?
Answer:
The acceleration of an object depends directly upon the net force acting upon the object, and inversely upon the mass of the object. As the force acting upon an object is increased, the acceleration of the object is increased. As the mass of an object is increased, the acceleration of the object is decreased.
Explanation:
hope it helps pls give me brainless
What is R2 in the circuit?
WILL GIVE BRAINLIEST !!!!
Answer:
1. Rₑq = 4 Ω
2. R₂ = 6 Ω
3. Vₜ = 12 V, V₁ = 12 V, V₂ = 12 V
4. Iₜ = 3 A, I₁ = 1 A, I₂ = 2 A
Explanation:
1. Determination of the equivalent resistance
Voltage (V) = 12 V
Current (I) = 3 A
Resistance (Rₑq) =?
V= IRₑq
12 = 3 × Rₑq
Divide both side by 3
Rₑq = 12 / 3
Rₑq = 4 Ω
Thus, the equivalent resistance (Rₑq) = 4 Ω
2. Determination of R₂.
Equivalent resistance (Rₑq) = 4 Ω
Resistance 1 (R₁) = 12 Ω
Resistance 2 (R₂)
Since the resistor are in parallel arrangement, the value of R₂ can be obtained as follow:
Rₑq = R₁ × R₂ / R₁ + R₂
4 = 12 × R₂ / 12 + R₂
Cross multiply
4(12 + R₂) = 12R₂
48 + 4R₂ = 12R₂
Collect like terms
48 = 12R₂ – 4R₂
48 = 8R₂
Divide both side by 8
R₂ = 48 / 8
R₂ = 6 Ω
3. Determination of the total voltage (Vₜ), V₁ and V₂.
From the question given above, the total voltage is 12 V
Since the resistors are arranged in parallel connection, the same voltage will go through them.
Thus,
Vₜ = V₁ = V₂ = 12 V
4. Determination of the total current (Iₜ), I₁ and I₂
From the question given above, the total current (Iₜ) is 3 A
Next, we shall determine I₁. Since the resistors are arranged in parallel connection, different current will pass through each resistor respective.
Vₜ = V₁ = 12 V
R₁ = 12 Ω
I₁ =?
V₁ = I₁R₁
12 = I₁ ×12
Divide both side by 12
I₁ = 12 / 12
I₁ = 1 A
Next, we shall determine I₂. This can be obtained as follow:
Iₜ = 3 A
I₁ = 1 A
I₂ =?
Iₜ = I₁ + I₂
3 = 1 + I₂
Collect like terms
I₂ = 3 – 1
I₂ = 2 A
What is one benefit to measuring your body’s flexibility?
A.
meeting the national requirement for flexibility
B.
determining your muscular strength
C.
tracking your flexibility improvements over time
D.
increasing the length of your life
Answer:
C
Explanation:
if you measure your body's flexibility then you can keep track of how flexible you have gotten over time
Can someone pls help! I’m stuck on c and d. I’ll rate your answer the brainliest
Answer:
i think is c
Explanation:
Answer:
C
Explanation:
C makes more sense than D, Because it says the minimum value is when it stays at rest.
PLZ WHAT I DOO
I BROKE A WINDOW WHAT I DO
Hmmmm, you either tell your parent, try to fix it, or blame it on the dog with a baseball bat that always comes on your yard and tries to eat you.
o(*￣▽￣*)ブ
Make a claim about which fossil in the diagram is the oldest. Use evidence and scientific reasoning to support your claim.
From the diagram, the fossil of fish is considered the oldest fossil. Because the oldest fossils are formed at the bottom whereas the others are at the top of the soil.
What are the fossils?When living organisms like plants, animals, and human beings are died, their bodies get buried in the form of sediments in the sand, rock water bodies, etc..,
It also includes the preserved remains of life for more than 10,000 years. It is the preserved remains, sediments, and impressions to trace the life of the organisms and their behavior.
When living organisms died and are buried in sand or mud, the tissues of living organisms get decomposed leaving the bones which is harder. After the organisms are buried in the sand or mud, several sediments, and sand was built over the top of the buried organisms.
These sand and sediments over the buried organisms eventually form the layer of rocks. This is how fossils are made and these fossils were identified when the rocks were broken or by cause of soil erosion.
The age of the fossils was identified by the stacks of layered rocks with the help of the superposition principle. The oldest fossils are present at the bottom of the rocks whereas the youngest fossils are present at the top of the rocks. This process is called Relative dating.
Hence, from the given diagram the fossil of fish is present at the bottom of the rock unlike the others fossils like monkeys and lizard. Thus, the oldest fossil is fish and the youngest one is a monkey.
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Tarzan, whose mass is 103 kg, is hanging at rest from a tree limb. Then he lets go and falls to the ground. Just before he lets go, his center of mass is at a height 2.4 m above the ground and the bottom of his dangling feet are at a height 1.5 above the ground. When he first hits the ground he has dropped a distance 1.5, so his center of mass is (2.4 - 1.5) above the ground. Then his knees bend and he ends up at rest in a crouched position with his center of mass a height 0.3 above the ground.
Required:
Consider the real system. What is the net change in internal energy for Tarzan from just before his feet touch to the ground to when he is in the crouched position?
Answer:
v₀ = 60.38 mi / h
With this stopping distance, the starting speed should have been 60.38 mi/h, which is much higher than the maximum speed allowed.
Explanation:
For this exercise let's start by using Newton's second law
Y axis
N-W = 0
N = W
X axis
fr = m a
the expression for the friction force is
fr = μ N
we substitute
μ mg = m a
μ g = a
calculate us
a = 0.620 9.8
a = 6.076 m / s²
now we can use the kinematics relations
v² = v₀² - 2 a x
suppose v = 0
v₀ = [tex]\sqrt{2ax}[/tex]Ra 2ax
let's calculate
v₀ = [tex]\sqrt{2 \ 6076 \ 60}[/tex]
v₀ = 27.00 m / s
let's slow down to the english system
v₀ = 27.0 m / s (3.28 ft / 1m) (1 mile / 5280 ft) (3600s / 1h)
v₀ = 60.38 mi / h
With this stopping distance, the starting speed should have been 60.38 mi/h, which is much higher than the maximum speed allowed.
1. A 455 g mass, hanging at rest on a spring, stretches the spring 22.4 cm beyond its relaxed
position. What is the spring constant of that spring?
Answer:
19.9 N/m
Explanation:
From the question,
Applying Hook's law
F = Ke.................. Equation 1
Where F = Force on the spring, k = spring constant, e = extension
But the force on the spring is the weight of the mass
Therefore,
mg = ke.................. Equation 2
Where m = mass. g = acceleration due to gravity
make e the subject of the equation
e = mg/e................ Equation 3
Given: m = 455 g = 0.455 kg, e = 22.4 cm = 0.224 m,
Constant: g = 9.8 m/s²
Substitute these values into equation 3
e = (0.455×9.8)/0.224
e = 19.9 N/m
The spring constant of the given spring is 20 N/m.
The given parameters:
Mass attached, m = 455 g = 0.455 kgExtension of the spring, x = 22.4 cm = 0.224 mThe spring constant is calculated by applying Hooke's law as follows;
[tex]F = kx\\\\mg = kx\\\\k = \frac{mg}{x} \\\\k = \frac{0.455 \times 9.8}{0.224} \\\\k = 20 \ N/m[/tex]
Thus, the spring constant of the spring is 20 N/m.
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Dynamic stretching is a series of movements that warm up the body before an intended activity. Which dynamic stretch would warm an individual before a one mile run
Answer:
They would likely do a whole series of dynamic stretches
Explanation:
It would include warming up the body and then dynamically stretching the lower body, and some upper body as well. This isn't a question with one specific answer
A rocket sled accelerates from rest for a distance of 645 m at 16.0 m/s2. A parachute is then used to slow it down to a stop. If the parachute gives the sled an acceleration of -18.2 m/s2 and there is 500.0 m of sled track remaining after the shoot opens, will the sled stop before running off the track? Show why or why not?
Answer:
the stopping distance is greater than the free length of the track, the vehicle leaves the track before it can brake
Explanation:
This problem can be solved using the kinematics relations, let's start by finding the final velocity of the acceleration period
v² = v₀² + 2 a₁ x
indicate that the initial velocity is zero
v² = 2 a₁ x
let's calculate
v = [tex]\sqrt {2 \ 15.0 \ 645}[/tex]
v = 143.666 m / s
now for the second interval let's find the distance it takes to stop
v₂² = v² - 2 a₂ x₂
in this part the final velocity is zero (v₂ = 0)
0 = v² - 2 a₂ x₂
x₂ = v² / 2a₂
let's calculate
x₂ = [tex]\frac{ 143.666^2 }{2 \ 18.2}[/tex]
x₂ = 573 m
as the stopping distance is greater than the free length of the track, the vehicle leaves the track before it can brake
Coherent light from a sodium-vapor lamp is passed through a filter that blocks everything except for light of a single wavelength. It then falls on two slits separated by 0.460 mm. In the resulting interference pattern on a screen 2.20 m away, adjacent bright fringes are separated by 2.82 mm. What is the wavelength of the light that falls on the slits
Answer:
[tex]5.896\times 10^{-7}\ \text{m}[/tex]
Explanation:
D = Distance of the screen from the light source = 2.2 m
d = Distance between slits = 0.46 mm
m = Order
Distance between adjacent bright fringes is 2.82 m
[tex]y_{m+1}-y_m=2.82\ \text{mm}\\\Rightarrow \dfrac{D(m+1)\lambda}{d}-\dfrac{Dm\lambda}{d}=2.82\times 10^{-3}\\\Rightarrow \dfrac{D\lambda}{d}(m+1-m)=2.82\times 10^{-3}\\\Rightarrow \lambda=\dfrac{d}{D}2.82\times 10^{-3}\\\Rightarrow \lambda=\dfrac{0.46\times 10^{-3}\times 2.82\times 10^{-3}}{2.2}\\\Rightarrow \lambda=5.896\times 10^{-7}\ \text{m}[/tex]
The wavelength of the light that falls on the slits is [tex]5.896\times 10^{-7}\ \text{m}[/tex].
How do particle motion and temperature change as a material absorbs heat?
What number belongs where "X" is to properly balance this equation?
2 NaCl →
2 Na + Ecl2
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2.
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Answer:
Option D: 1
Explanation:
The chemical equation given is;
2NaCl = 2Na + XCl2
We want to find the value of X.
On the left hand side, we can see we have 2 moles of both Na and Cl.
On the right hand side, we can see that we have 2 moles of Na and also 2 moles of Cl. Thus, the equation is balanced and as such X = 1
1 ) when a ball is projected upwords its time of rising is ...............the time of falling .
a) greater than b) smaller than c) equal to d ) double
2 ) when an object falls freely under the effect of gravity , the distance moved is
a ) directly proportional to time
b ) inversely proportional to time
c ) directly proportional to square of time
d ) inversely proportional to square of time.
Answer:
correct answer is C
Explanation:
In this exercise, you are asked to complete the sentences so that the sentence makes sense.
1) in projectile launching, the only force that acts is gravity in the vertical direction, so the time of going up is EQUAL to the time of going down
correct answer C
2) when a body falls freely, the acceleration is the ratio of gravity, therefore if it starts from rest, its height is
y = v₀ t - ½ gt²
v₀ = 0
y = -1/2 g t²
so the position is not proportional to the square of the time
correct answer is C
What does the force of attraction called gravity act on?
A. every mass
B. no masses
C. nearby masses
D. select masses
Answer:
Every mass
Explanation:
Because Force of gravity always act toward the center of the earth , so when an object is thrown up ,the force of gravity will act in opposite direction of motion ,that's toward the center of earth. The force is towards the center of the Earth (more or less). which gives it time get touch every mass.
The gravitational force of attraction exists between every objects in the universe that are having mass. So, the correct option is A.
What is meant by the force of gravity ?Force of gravity is defined as the force of attraction experienced by bodies due to the gravitational field of earth.
Here,
The gravitational force is the attractive force experienced by any body that have mass. Gravity is an attractive force such that every bodies that are having mass in the earth are being attracted towards the centre of earth.
The equation of gravitational force is given by,
F = GMm/r²
where G is the gravitational constant of earth, M is the mass of earth and m is the mass of the body which is being attracted towards earth's centre, and r is the distance between earth and the body.
From the equation, it is shown that gravitational force is proportional to the masses. More the mass of the objects, more will be the gravitational force of attraction existing between them.
Hence,
The gravitational force of attraction exists between every objects in the universe that are having mass.
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Calculate the volume occupied by a glass cup having a mass of 260 g knowing that the
density of glass is equal to 2.6 g/cm3
Answer:
100 milliliters
Explanation:
advice students on how to manage stress throughout their studies
Answer:
Drink water
Make your find fresh by doing the stuff you love too ❤️
Prove the correctness of this equation s=vt + 1/2at
Answer:
The formula is dimensionally correct.
Explanation:
Given
[tex]s = ut + \frac{1}{2}at^2[/tex]
Required
Prove its correctness
Write out the dimension of each:
[tex]s = M^0LT^0[/tex] --- displacement
[tex]ut = M^0LT^{-1} * T[/tex] --- velocity * time
[tex]\frac{1}{2}at^2 = M^0LT^{-2} * T^2[/tex] --- acceleration * square of time
The expression becomes:
[tex]s = ut + \frac{1}{2}at^2[/tex]
[tex]M^0LT^0 = M^0LT^{-1} * T + M^0LT^{-2} * T^2[/tex]
Apply law of indices
[tex]M^0LT^0 = M^0LT^{-1+1} + M^0LT^{-2+2}[/tex]
[tex]M^0LT^0 = M^0LT^{0} + M^0LT^{0}[/tex]
[tex]M^0LT^0 = M^0LT^{0}[/tex]
Both sides of the equation are equal
Help me pls???!!
In the circuit shown, the
battery voltage, V = 12V and the load resistance, R = 252.
The ammeter reading is____
A.
The Voltmeter reading is_____
V.
Answer:
A. I = V / R = 12 / 252 = .048 amps
V = I * R = .048 * 252 = 12 V
V is also the reading the voltage across the battery (12 Volts)
What is earth's magnetic field made of
Answer:
if you have a rotating electric current it will create a magnetic field on earth flowing of liquid metal in the outer core of the planets General Health recurrence the rotation of earth on its Axis causes this electric current to form a magnetic field which extends around the planet.
Explanation:. please give me brainlest
Part C
What happens when you increase the frequency of the water drops? What happens to the wavelength of the waves ont
surface of water?
Answer:the wave lengths are shorter and faster
Explanation:
Plato
the
11. A sinusoidal A.C has a maximum value of 15A.
1) What are its r.m.s values?
ii) If the time is recorded from the instant the current is zero and is becoming
positive, what is the instantaneous value of the current after 1/300s, given the
frequency is 50 Hz.
Answer:
1.) 10.61 A
2.) 0.27 A
Explanation:
Given that a sinusoidal A.C has a maximum value of 15A.
1) What are its r.m.s values?
ii) If the time is recorded from the instant the current is zero and is becoming
positive, what is the instantaneous value of the current after 1/300s, given the
frequency is 50 Hz.
Solution.
1.)
The r.m.s current = peak current/root 2
The r.m.s current = 0.7071 × 15
The r.m.s current = 10.61 A
2.)
Given that
Time = 1/300 s
Frequency = 50 Hz
Instantaneous current can be calculated by using the formula
I = I sin wt
Where w = 2πf
Instantaneous current = 15( sin 2πft)
I = 15 × sin ( 2 × 3.143 × 50 × 1/300 )
I = 15 × sin ( 1.047 )
I = 15 × 0.01827
I = 0.27 A
Therefore, the instantaneous current is 0.27A
Two polarizing sheets have their transmission axes crossed so that no light is transmitted. A third sheet is inserted so that its transmission axis makes an angle with the transmission axis of the first sheet. (a) Derive an expression for the intensity of the transmitted light as a function of (b) Show that the intensity transmitted through all three sheets is maximum when\
Answer:
a) I= I₀ (cos²θ - cos⁴θ) b) 75.5º
Explanation:
a) For this exercise we must use Malus's law
I = I₀ cos² θ
where tea is the angle between the two polarizers.
We apply this expression to our case
* Polarizer 1 suppose that it is vertical and polarizer 2 (intermediate) is at an angle θ with respect to the vertical
I₁ = I₀ cos² θ
* We analyze for the polarity 2 and the last polarizer 3 which indicate that it must be at 90º from the first one, therefore it must be horizontal.
The angle of polarizers 2 and 3 is θ' measured from the horizontal, if we measure with respect to the vertical
θ₂ = 90- θ’ = θ
fiate that in the exercise we must take a reference system and measure everything with respect to this system.
I = I₁ cos² θ'
we substitute
I = (I₀ cos² tea) cos² (θ - 90)
cos (θ -90) = cos θ cos 90 + sin θ sin 90 = sin θ
I = Io cos² θ sin² θ
1= cos²θ+ sin²θ
sin²θ = 1 - cos²θ
I= I₀ (cos²θ - cos⁴θ)
b) to find when the intensity is maximum,
we can use that we have an extreme point when the drift is zero
[tex]\frac{dI}{d \theta}[/tex] = 0
\frac{dI}{d \theta}= Io (2 cos θ - 4 cos³θ) = 0
whereby
cos θ - 2 cos³ θ = 0
cos θ ( 1 - 2 cos² θ) = 0
The zeros of this function are in
θ = 90º
1-2cos²θ =0 cos θ = 0.25 θ = 75.5º
Let's analyze this two results for the angle of 90º the intnesidd is zero with respect to the first polarizer, so it is not an acceptable solution.
Consequently, the angle that allows the maximum intensity to pass is 75.5º
A small rubber wheel is used to drive a large pottery wheel. The two wheels are mounted so that their circular edges touch. The smalldrive-wheel has a radius of 2.20 cm and accelerates at the rate of 8.00 rad/s2, and it is in contact with the pottery wheel (radius 28.0 cm). Both wheels move without slipping.The rubber drive wheel rotates in the clockwise sense.
Required:
a. Find the angular acceleration (both magnitude and direction) of the large pottery wheel.
b. Calculate the tune it takes the pottery wheel to reach its required speed of 60 rpm. if both wheels start from rest.
Answer:
[tex]0.629\ \text{rad/s}^2[/tex] counterclockwise
[tex]9.98\ \text{s}[/tex]
Explanation:
[tex]r_1[/tex] = Small drive wheel radius = 2.2 cm
[tex]\alpha_1[/tex] = Angular acceleration of the small drive wheel = [tex]8\ \text{rad/s}^2[/tex]
[tex]r_2[/tex] = Radius of pottery wheel = 28 cm
[tex]\alpha_2[/tex] = Angular acceleration of pottery wheel
As the linear acceleration of the system is conserved we have
[tex]r_1\alpha_1=r_2\alpha_2\\\Rightarrow \alpha_2=\dfrac{r_1\alpha_1}{r_2}\\\Rightarrow \alpha_2=\dfrac{2.2\times 8}{28}\\\Rightarrow \alpha_2=0.629\ \text{rad/s}^2[/tex]
The angular acceleration of the pottery wheel is [tex]0.629\ \text{rad/s}^2[/tex].
The rubber drive wheel is rotating in clockwise direction so the pottery wheel will rotate counterclockwise.
[tex]\omega_i[/tex] = Initial angular velocity = 0
[tex]\omega_f[/tex] = Final angular velocity = [tex]60\ \text{rpm}\times \dfrac{2\pi}{60}=6.28\ \text{rad/s}[/tex]
t = Time taken
From the kinematic equations of linear motion we have
[tex]\omega_f=\omega_i+\alpha_2t\\\Rightarrow t=\dfrac{\omega_f-\omega_i}{\alpha_2}\\\Rightarrow t=\dfrac{6.28-0}{0.629}\\\Rightarrow t=9.98\ \text{s}[/tex]
The time it takes the pottery wheel to reach the required speed is [tex]9.98\ \text{s}[/tex]
A closed, rigid container holding 0.2 moles of a monatomic ideal gas is placed over a Bunsen burner and heated slowly, starting at a temperature of 300 K. The initial pressure of the ideal gas is atmospheric pressure, and the final pressure is four times the initial pressure.
Determine the following:
a. the change in the internal energy of the gas.
b. the work done by the gas.
c. the heat flow into or out of the gas.
Answer:
a) 2250 J
b) 0 J
c) 2250 J
Explanation:
a) Since, the process is isochoric
the change in internal energy
[tex]\Delta U = n C_v(T_f-T_i)[/tex]
Here, n = 0.2 moles
Cv = 12.5 J/mole.K
We have to find T_f so we can use gas equation as
[tex]\frac{P_1V_1}{P_2V_2} =\frac{T_i}{T_f}\\Since, V_1=V_2 [isochoric/process]\\\Rightarrow \frac{P_{atm}}{4P_{atm}} = \frac{300}{T_f} \\\Rightarrow T_f = 1200 K[/tex]
So, [tex]\Delta U= 0.2\times12.5(1200-300)\\=2250 J[/tex]
b) Since, the process is isochoric no work shall be done.
c) By first law of thermodynamics we have
[tex]\Delta U = Q-W\\Since, W = 0\\\Delta U = Q\\Therefore, Q = 2250 J[/tex]
Since, Q is positive 2250 J of heat will flow into the system.
Definition of continental polar
cold, dry, and stable air masses .
what is the minimum effort required to raise the block?
Answer:
2000 N.
Explanation:
From the question given above, the following data were obtained:
Load (L) = 8000 N
Mechanical advantage (MA) = 4
Effort (E) =?
The mechanical advantage of a machine is simply defined as:
Mechanical advantage = Load / Effort
MA = L / E
With the above formula, we can obtain the effort used to raise the load of 8000 N as follow:
Load (L) = 8000 N
Mechanical advantage (MA) = 4
Effort (E) =?
MA = L / E
4 = 8000 / E
Cross multiply
4 × E = 8000
Divide both side by 4
E = 8000 / 4
E = 2000 N
Thus, the effort used to raised the load is 2000 N.
a violin is less than 0.5 m long. a bass fiddle is more than 1.5 m long. which instrument do you expect to be able to play notes with a lower pitch and why?
Explanation:
When there is a high frequency sound the speed of the vibrations is faster and makes a high pitch sound. When there is a low frequency sound the speed of the vibrations is slower and makes a lower pitch sound.
I really need the answer
Answer:
The first answer is correct. All of the other options include sound, which travels by material force, and can not be transmitted in a vacuum. Infra-red, radio, and microwaves are all different frequencies of light, and can thus travel through a vacuum.