Answer:
A boat travels for three hours with a... A boat travels for three hours with a current of 3 mph and then returns the same distance against the current in four hours. What is the boat's speed in still water?
Explanation:
A plano concave lens is one that has a surface that curves inward, making the lens thinner at its center than at its edges. Its effect on light is :_______.
a.) to make it appear as if incident parallel light is coming from a point close to the lens on the opposide side from the light source
b.) the diverge in incident beam of light
c.) to converge light to a focus
d.) to make it appear as if incident parallel light is coming from a point close to the lens on the same side as the light source
Answer:
b.) the diverge in incident beam of light
Explanation:
A lens refers to any refracting surface. The manner in which a lens is curved tells whether it is a concave(diverging) lens or a convex (converging) lens.
A convex lens is thicker at the center than at the edges. It makes light to converge at a point.
A concave lens is is thinner at the center than at the edges. It makes light to appear to diverge from a point, hence the answer above.
Which of the following is not a unit of speed *
a) m/s
b) km/s
c) mph [miles per hour]
d) light year
Answer:
I think it's light year but there shouldn't be also km/s but km/h
⦁ An electron is moving through a 10 T magnetic field at a speed of 3.5 x107m/s perpendicular to the direction of the field. What is the force that applied on the charge?
Answer:
F = 5.6 10⁻¹¹ N
Explanation:
The magnetic force is given by
F = q v x B
The bold indicate vectors, the scalar form of this expression is
F = q v B sin θ
in this case they indicate that the speed and the magnetic field are perpendicular, so the angle is 90º and the sin 90 = 1
F = q v B
the magnitude of the force is
F = 1.6 10⁻¹⁹ 3.5 10⁷ 10
F = 5.6 10⁻¹¹ N
All the questions are in the photos above. Thanks guys!
Answer:
right
Explanation:
A device known as an optical resonator is used in lasers. An optical resonator consists of an arrangement of mirrors that reflect electromagnetic radiation back and forth within an empty cavity. The electromagnetic radiation within the cavity reflects off of the mirrors multiple times. The mirrors are precisely placed so that only particular frequencies can survive within the cavity via constructive interference. All other frequencies are suppressed via destructive interference. The end result is a beam of light of a certain frequency.
An optical resonator of the type described above depends on the tendency of light to
A. behave as a wave.
B. excite atoms to certain energy levels.
C. excite electrons to certain energy levels.
D. behave as a particle.
Answer:
A. The resonator behaves as a wave guide (a hollow pipe used as a transmission line). The characteristics of the pipe depend on the type of the wave to be transmitted.
Consider a block of mass m at rest on an inclined plane of angle theta. An acrobat of mass m_A is standing on the top corner of the block so that their weight presses vertically (perpendicular to the flat ground under the incline) downward. If the coefficient of static friction between the block and the incline is mu_s find an expression relating m_A, m, theta, and mu_s just before the block begins slipping. If the condition for slipping does not involve some of these parameters, leave them out.
Enter your expression as best you can and I will check it. Do not forget to upload your work as well.
Answer:
μ = tan θ
Explanation:
For this exercise let's use the translational equilibrium condition.
Let's set a datum with the x axis parallel to the plane and the y axis perpendicular to the plane.
Let's break down the weight of the block
sin θ = Wₓ / W
cos θ = W_y / W
Wₓ = W sin θ
W_y = W cos θ
The acrobat is vertically so his weight decomposition is
sin θ = = wₐₓ / wₐ
cos θ = wₐ_y / wₐ
wₐₓ = wₐ sin θ
wₐ_y = wₐ cos θ
let's write the equilibrium equations
Y axis
N- W_y - wₐ_y = 0
N = W cos θ + wₐ cos θ
X axis
Wₓ + wₐ_x - fr = 0
fr = W sin θ + wₐ sin θ
the friction force has the formula
fr = μ N
fr = μ (W cos θ + wₐ cos θ)
we substitute
μ (Mg cos θ + mg cos θ) = Mgsin θ + mg sin θ
μ = [tex]\frac{(M +m) \ sin \ \theta }{(M +m) \ cos \ \theta }[/tex]
μ = tan θ
this is the minimum value of the coefficient of static friction for which the system is in equilibrium.
A skater spins with an angular speed of 5.9 rad/s with her arms outstretched. She lowers her arms, decreasing her moment of inertia by a factor of 1.7. Ignoring friction on the skates, determine the ratio of her final kinetic energy to her initial kinetic energy.
Answer:
the ratio of her final kinetic energy to her initial kinetic energy is 1.7.
Explanation:
Given;
initial angular speed, ω₁ = 5.9 rad/s
let her initial moment of inertia = I₁
her final moment of inertia [tex]I_2 = \frac{I_1}{1.7}[/tex]
Apply the principle of conservation of angular momentum to determine the final angular speed of the girl;
[tex]\omega_1I_1 = \omega_f I_2\\\\\omega_f = \frac{\omega _1 I_1}{I_2} \\\\\omega_f = \frac{5.9 \times I_1}{I_1/1.7} \\\\\omega = 5.9 \times 1.7 \\\\\omega_f = 10.03 \ rad/s[/tex]
The initial rotational kinetic energy is given as;
[tex]K.E_I = \frac{1}{2}I_1 \omega_I ^2[/tex]
The final rotational kinetic energy is given as;
[tex]K.E_f = \frac{1}{2}I_2 \omega_f ^2[/tex]
The ratio of her final kinetic energy to her initial kinetic energy is given as;
[tex]\frac{K.E_f}{K.E_I}= \frac{\frac{1}{2}I_2 \omega_f^2 }{\frac{1}{2} I_1\omega _1^2} \\\\\frac{K.E_f}{K.E_I}= \frac{I_2 \omega_f^2}{ I_1\omega _1^2} \\\\\frac{K.E_f}{K.E_I}= \frac{I_1/1.7 \times \omega_f^2}{ I_1 \times \omega _1^2} \\\\\frac{K.E_f}{K.E_I}= \frac{ \omega_f^2}{ 1.7 \omega _1^2} \\\\\frac{K.E_f}{K.E_I}= \frac{ (10.03)^2}{ 1.7(5.9)^2} = \frac{17}{10} = 1.7[/tex]
Therefore, the ratio of her final kinetic energy to her initial kinetic energy is 1.7.
Chemotherapy is used to treat
cervical cancer.
endometriosis.
undescended testicles.
benign prostatic hypertrophy.
Answer:
Cervical cancer
Explanation:
Chemotherapy is a common treatment or most cancers
Answer:
A
Explanation:
What are the two forces acting on a balanced hot air balloon.
of
O a. Gravity and Weight
O b.
Air resistance and upthrust
O c. Applied force and upthrust
d.
Gravity and air resistance
Answer:
I want to say option C) Applied force and upthrust.
Explanation:
Sorry if my answer is wrong. You can look in your book or study up on the website.
You and a friend are playing with a Coke can that you froze so it's solid to demonstrate some ideas of Rotational Physics. First, though, you want to calculate the Rotational Kinetic Energy of the can as it rolls down a sidewalk without slipping. This means it has both linear kinetic energy and rotational kinetic energy. [The freezing only matters because if there is liquid inside, the calculation for the Moment of inertia becomes more complicated]. A Coke can can be modeled as a solid cylinder rotating about its axis through the center of the cylinder. This can has a mass of 0.33 kg and a radius of 3.20 cm. You'll need to look up the equation for the Moment of Inertia in your textbook. It is rotating with a linear velocity of 6.00 meters / second in the counter-clockwise (or positive) direction. You can use this to determine the angular velocity of the can (since it is rolling without slipping). What is the Total Kinetic Energy of the Coke can
Answer:
K_{total} = 8.91 J
Explanation:
In this exercise you are asked to find the kinetic energy of the can of coca-cola
K_total = K_ {Translation} + K_ {rotation}
the translational kinetic energy is
K_ {translation} = ½ m v²
the kinetic energy of rotation is
K_ {rotation} = ½ I w²
The moment of inertia of a cylinder is
I = ½ m r²
we substitute
K_ {total} = ½ m v² + ½ (½ m r²) w²
angular and linear velocity are related
v = w r
we substitute
K_ {total} = ½ m v² + ¼ m r² v² / r²
K_ {total} = m v² (½ + ¼)
K_ {total} = ¾ m v²
let's calculate
K_ {total} = ¾ 0.33 6.00²
K_{total} = 8.91 J
Friction forces cannot change the speed and direction of an object True or false
Answer:
false
Explanation:
This statement is false since frictional force always reduces the speed of and object and also always acts opposite to the direction of a motion. The correct answer is False
FRICTION
Frictional force is a force that opposes motion of an object.
When an object is in motion, the speed of the object will be constant only when the forces acting on the object are balanced. That is, the frictional force balanced or equal to the force applied. A balanced force cannot change the speed and direction of an object in motion.
There will be change in speed and direction when forces acting on the object are not balanced.
Friction forces cannot change the speed and direction of an object. This statement is false since frictional force always reduces the speed of and object and also always acts opposite to the direction of a motion.
Therefore, the correct answer is False.
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which of the following best defines spring constant ?
a. the amount of force needed to extend or compression of a spring for every 1 kilogram of the spring.
b. the amount of force needed every 1 meter of stretch or compression of the spring.
c. the amount of energy needed to extend or compress a spring for every 1 kilogram of mass of the spring.
d. the amount of energy needed for every 1 meter of stretch or compression of the spring.
Answer:
your answer gonna be The letter C is the correct answer
Consider the model of the energy transformation of this system. What can you say about N and M in the model?
A) M < N
B) N = M
C) N < M
D) N + M =
Model of the energy transformation of this system we can say about N and M in the model is M < N.
What is energy?Energy is the ability or capability to do tasks, such as the ability to move an item (of a certain mass) by exerting force. Energy can exist in many different forms, including electrical, mechanical, chemical, thermal, or nuclear, and it can change its form.
The model shows the energy transformation in electrical appliance Fan the is lass of energy in form of heat so M < N.
Model of the energy transformation of this system we can say about N and M in the model is M < N.
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What is oscillating to form a light wave?
O Electric and Magnetic Fields
O Matter
O Light is only a particle, not a wave
O The Luminiferous Aether
A level of
class one
has a length of
4m
and is
able
to lift
a load of 40kg with a force of 40N. Find
the position Of
fulcrum.
Answer:
x = 2 meters.
Explanation:
Let the position (distance) of fulcrum to the load be x.
Given the following data;
Load = 40 kg
Effort (force) = 40 Newton
Effort arm = 4 - x
To find the position of the fulcrum, we would use the expression;
Effort * effort arm = load * load arm
40 * (4 - x) = 40 * x
160 - 40x = 40x
160 = 40x + 40x
160 = 80x
x = 160/80
x = 2 meters
Therefore, the position (distance) of fulcrum to the load is 2 meters.
Two long, straight wires are separated by a distance of 32.2 cm. One wire carries a current of 2.75 A, the other carries a current of 4.33 A. (a) Find the force per meter exerted on the 2.75-A wire. (b) Is the force per meter exerted on the 4.33-A wire greater than, less than, or the same as the force per meter exerted on the 2.75-A wire
Answer:
a)[tex]\frac{F_1}{L}=1.95*10^-^5N[/tex]
b)[tex]\frac{F_2}{L}=1.95*10^-^5N[/tex]
Explanation:
From the question we are told that:
Distance between wires [tex]d=32.2[/tex]
Wire 1 current [tex]I_1=2.75[/tex]
Wire 2 current [tex]I_2=4.33[/tex]
a)
Generally the equation for Force on [tex]l_1[/tex] due to [tex]I_2[/tex] is mathematically given by
[tex]F_1=I_1B_2L[/tex]
Where
B_2=Magnetic field current by [tex]I_2[/tex]
[tex]B_2=\frac{\mu *i_2}{2\pi d}[/tex]
Therefore
[tex]F_1=I_1B_2L[/tex]
[tex]F_1=I_1(\frac{\mu *i_2*l_1}{2\pi d})L[/tex]
[tex]\frac{F_1}{L} =\frac{4*\pi*10^{-7}*2.75*4.33*100 }{2*\pi*12.2 }[/tex]
[tex]\frac{F_1}{L}=1.95*10^-^5N[/tex]
b)
Generally the equation for Force on [tex]I_2[/tex] due to [tex]I_1[/tex] is mathematically given by
[tex]F_2=I_2B_1L[/tex]
Where
B_1=Magnetic field current by [tex]I_2[/tex]
[tex]B_1=\frac{\mu *I_1}{2\pi d}[/tex]
Therefore
[tex]\frac{F_2}{L} =I_2(\frac{\mu *I_1*I_2}{2\pi d})[/tex]
[tex]\frac{F_2}{L}=1.95*10^-^5N[/tex]
What is a negative effect of increased carbon dioxide within the carbon cycle?
Answer:
Explanation:
Carbon dioxide controls the amount of water vapor in the atmosphere and thus the size of the greenhouse effect. Rising carbon dioxide concentrations are already causing the planet to heat up.
PLZ help 10 points!!! space question!
Answer:
B. They are smaller and made of rocky material
Explanation:
i think it's right??
Examine the model of the phrases of the moon. Which of these statements is true, based on the information shown in the model.
Select ALL that apply.
A) The new moon occurs when the moon is the sun.
B) The quarter moons occur when the moon is closest to the sun
C) The Full moons Occur when the moon is farthest from the earth.
D) The relative position of the moon, Earth, Sun causes the moon phases.
E) Only half of the moon is illuminated by the sun at any point in the cycle
Answer:
D and E
Explanation:
I had this quiz as well so-
Planet X has a moon similar to Earth’s moon.
Which path would this moon’s orbit take?
If acceleration is zero what statement about velocity is
true *
A)Velocity is zero
B)Velocity is constant
C)Velocity cannot be determined
D) Velocity is changing
Answer: A
Velocity is zero because the acceleration isn't affected, and velocity is the rate of change, so it can't be any other options.
Answer:
B)Velocity is constantExplanation:
If an object moves with a velocity and there is no acceleration, then the velocity remains constant. His velocity after five second will be equal to his initial velocity.#keeplearning dude:)A wheel rotating about a fixed axis with a constant angular acceleration of 2.0 rad/s2 starts from rest at t = 0. The wheel has a diameter of 20 cm. What is the magnitude of the total linear acceleration of a point on the outer edge of the wheel at t = 0.60 s? Hint: To find total linear acceleration (in m/s2)you need to have tangential and radial acceleration . Tangential acceleration can be calculated using angular acceleration at=rα To find redial acceleration you need to calculate final linear speed of that point and use ar=vf2r . And vf=rωf.
Answer:
The total linear acceleration is approximately 0.246 meters per square second.
Explanation:
The total linear acceleration ([tex]a[/tex]) consist in two components, radial ([tex]a_{r}[/tex]) and tangential ([tex]a_{t}[/tex]), in meters per square second:
[tex]a_{r} = \omega^{2}\cdot r[/tex] (1)
[tex]a_{t} = \alpha \cdot r[/tex] (2)
Since both components are orthogonal to each other, the total linear acceleration is determined by Pythagorean Theorem:
[tex]a = \sqrt{a_{r}^{2}+a_{t}^{2}}[/tex] (3)
Where:
[tex]r[/tex] - Radius of the wheel, in meters.
[tex]\omega[/tex] - Angular speed, in radians per second.
[tex]\alpha[/tex] - Angular acceleration, in radians per square second.
Given that wheel accelerates uniformly, we use the following kinematic equation:
[tex]\omega = \omega_{o}+ \alpha\cdot t[/tex] (4)
Where:
[tex]\omega_{o}[/tex] - Initial angular speed, in radians per second.
[tex]t[/tex] - Time, in seconds.
If we know that [tex]r = 0.1\,m[/tex], [tex]\alpha = 2\,\frac{rad}{s^{2}}[/tex], [tex]\omega_{o} = 0\,\frac{rad}{s}[/tex] and [tex]t = 0.60\,s[/tex], then the total linear acceleration is:
[tex]\omega = \omega_{o}+ \alpha\cdot t[/tex]
[tex]\omega = 1.2\,\frac{rad}{s}[/tex]
[tex]a_{r} = \omega^{2}\cdot r[/tex]
[tex]a_{r} = 0.144\,\frac{m}{s^{2}}[/tex]
[tex]a_{t} = \alpha \cdot r[/tex]
[tex]a_{t} = 0.2\,\frac{m}{s^{2}}[/tex]
[tex]a = \sqrt{a_{r}^{2}+a_{t}^{2}}[/tex]
[tex]a \approx 0.246\,\frac{m}{s^{2}}[/tex]
The total linear acceleration is approximately 0.246 meters per square second.
What type of electromagnetic radiation is being shown in the picture?
A. Gamma rays
B. Ultraviolet radiation
C. X-rays
D. Infrared radiation
Answer:
I think D. Infrared radiation.
Answer:
infrared radition
Explanation:
valid
Increasing the telescope diameter beyond the value found in part (a) will increase the light-gathering power of the telescope, allowing more distant and dimmer astronomical objects to be studied, but it will not improve the resolution. In what ways are the Keck telescopes (each of 10-m diameter) atop Mauna Kea in Hawaii superior to the Hale Telescope (5-m diameter) on Palomar Mountain in California
Answer:
Ability of the Keck telescope to capture more distant object despite been atop Mauna kea that Hale Telescope may not capture even if it is atop Palomar mountain in California
Explanation:
If increasing the Diameter of a Telescope beyond a given value will increase the ability of the telescope to capture more light and also capture astronomical objects located in a very distant position without improving resolution.
Hence the superiority of Keck telescope atop Mauna Kea over Hale Telescope atop Palomar mountain in California is the ability of the Keck telescope to capture more distant object despite been atop Mauna kea that Hale Telescope may not capture even if it is atop Palomar mountain in California
Can someone take there time and answer this :)
Answer: I think B.)
Explanation:
If objects are traveling in opposite directions, what do you know about the signs of their momenta?
Explanation:
the impulse and momentum change on each object are equal in magnitude and opposite in directions. Thus the total momentum is reserved
They have no overall momentum at all. They are travelling in opposing directions yet having the same mass and velocity. Their momentum vectors add up to exactly zero when added together.
What If objects are travelling in opposite directions?When two objects collide, opposite-direction forces of equal magnitude are exerted to each item. When there are such pressures, it usually happens that one item speeds up and gains momentum, while the other object slows down (lose momentum).
Think about a situation where two similar objects are going in opposite directions at the same speed. It's noteworthy to note that despite both items moving, the momentum of the system as a whole is zero because the oppositely oriented vectors cancel out.
Therefore, Every object experiences an equal but opposite change in impulse and momentum. Thus, the entire momentum is held back.
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The instantaneous speed of a cat running 400 meters in 20 seconds is 20 meters per second.
OTrue
O False
Answer:
true
Explanation:
400/20=20
Answer:
True
Explanation:
400/20=20mps
plz mark me as brainliest.
What is surface tension
Answer:
Surface tension is, the surface where the water meets the air, water molecules cling even more tightly to each other.
A ball is attached to one end of a wire, the other end being fastened to the ceiling. The wire is held horizontal, and the ball is released from rest. It swings downward and strikes a block initially at rest on a horizontal frictionless surface. Air resistance is negligible, and the collision is elastic. The masses of the ball and block are, respectively, 1.48 kg and 2.77 kg, and the length of the wire is 1.11 m. Find the velocity of the ball just after the collision.
Answer: Velocity of the ball just after the collision is -1.414 m/s.
Explanation:
As energy is conserved in a reaction so here, energy before collision will be equal to the energy after collision.
[tex]E_{before} = mgh = E_{after} = \frac{1}{2}mv_{o}^{2}[/tex]
where,
m = mass
g = gravitational energy = [tex]9.8 m/s^{2}[/tex]
h = height or length
[tex]v_{o}[/tex] = initial velocity
Also here, height is the length of wire. Let the height be denoted by 'L'. Therefore,
[tex]\frac{1}{2}mv_{o}^{2} = mgL\\v_{o}^{2} = 2gL\\v_{o} = \sqrt{2gL}\\= \sqrt{2 \times 9.8 m/s^{2} \times 1.11 m}\\= 4.66 m/s[/tex]
Formula used to calculate velocity after the collision is as follows.
[tex]v_{f ball} = v_{o} [\frac{m_{ball} - m_{block}}{m_{ball} + m_{block}}][/tex]
where,
[tex]v_{f ball}[/tex] = final velocity of ball after collision
[tex]m_{ball}[/tex] = masses of ball
[tex]m_{block}[/tex] = masses of block
Substitute the values into above formula as follows.
[tex]v_{f ball} = v_{o} [\frac{m_{ball} - m_{block}}{m_{ball} + m_{block}}]\\= 4.66 m/s [\frac{1.48 kg - 2.77 kg}{1.48 kg + 2.77 kg}]\\= 4.66 m/s \times (-0.303)\\= -1.414 m/s[/tex]
Thus, we can conclude that velocity of the ball just after the collision is -1.414 m/s.
In a physics lab experiment for the determination of moment of inertia, a team weighs an object and finds a mass of 4.07 kg. They then hang the object on a pivot located 0.155 m from the object's center of mass and set it swinging at a small amplitude. As two of the team members carefully count 113 cycles of oscillation, the third member measures a duration of 247 s. What is the moment of inertia of the object with respect to its center of mass about an axis parallel to the pivot axis
Answer:
I = 0.65 kgm²
Explanation:
Since the mass is an inertial pendulum, we use the formula for the period, T of an inertial pendulum.
T = 2π√(I/mgh) where I = moment of inertia of object about pivot point, m = mass of object5 = 4.07 kg, g = acceleration due to gravity = 9.8 m/s² and h = distance of center of mass of object from pivot point = 0.155 m.
Given that the team measures 113 cycles of oscillation in 247 s, the period, T = time of oscillations/total number of oscillations = 247 s/113 oscillations = 2.186 s/oscillation
So, T = 2.186 s
We now find I by making it subject of the formula in the equation for T.
So,
T = 2π√(I/mgh)
dividing both sides by 2π, we have
T/2π = √(I/mgh)
squaring both sides, we have
(T/2π)² = [√(I/mgh)]²
T²/4π² = I/mgh
multiplying both sides by mgh, we have
T²mgh/4π² = I
I = T²mgh/4π²
substituting the values of the variables into the equation, we have
I = T²mgh/4π²
I = (2.186 s)² × 4.07 kg × 9.8 m/s² × 0.155 m/4π²
I = 4.778 s² × 4.07 kg × 9.8 m/s² × 0.155 m/4π²
I = 29.539 kgm²/4π²
I = 0.748 kgm²
Now I = I' + mh² (parallel axis theorem) where I' = moment of inertia of object about its center of mass, m = mass of object = 4.07 kg and h = distance of center of mass object from pivot point.
So, I' = I - mh²
Substituting the values of the variables into the equation, we have
I' = I - mh²
I' = 0.748 kgm² - 4.07 kg × (0.155 m)²
I' = 0.748 kgm² - 4.07 kg × 0.02403 m²
I' = 0.748 kgm² - 0.098 kgm²
I = 0.65 kgm²