Answer:
-2R
Explanation:
The focal length can be calculated using this formula
1/f = (n1/n2-1)(1/r1-1/r2)
1/f = (1/1.33-1)(1/r + 1/r)
= -0.133/1.33(2/R)
F = -2R
The focal length is this
What is the final speed of a free electron accelerated from rest through a potential difference of -120 V? The mass of the electron is 9.11x10-31kg. You need to express the speed in km/s.
You should round your answer to an integer, indicate only the number, do not include the unit.
Answer:
The final speed of the electron is 6,497 km/s
Explanation:
Given;
mass of the electron, m = 9.11 x 10⁻³¹ kg
electron potential, V = -120 V
Apply work energy theorem;
¹/₂mv² = eV
Where;
v is the final speed of the electron
e is the charge of the electron, = 1.602 x 10⁻¹⁹ C
[tex]v = \sqrt{\frac{2eV}{m} }\\\\v = \sqrt{\frac{2(1.602*10^{-19})(120)}{9.11*10^{-31}} }\\\\v = 6496473.75 \ m/s\\\\v = 6,497 \ km/s[/tex]
Therefore, the final speed of the electron is 6,497 km/s
Question 4 of 10
How does the electric current of an AC generator differ from that of a DC
generator?
O A. It is much stronger.
OB. It flows through the permanent magnets.
C. It is much weaker.
D. It constantly reverses direction.
Answer:
D) it constantly reverses direction
Explanation:
Just took the test
A 72.0-kg person pushes on a small doorknob with a force of 5.00 N perpendicular to the surface of the door. The doorknob is located 0.800 m from axis of the frictionless hinges of the door. The door begins to rotate with an angular acceleration of 2.00 rad/s2, What is the moment of inertia of the door about the hinges? A) 2.74 kg m2 B) 1.88 kg m2 C) 0.684 kg m2 D) 4.28 kg m2 E) 7.52 kg m2
Answer:
[tex]I=2\ kgm^2[/tex]
Explanation:
Given that,
Mass of a person, m = 72 kg
Force acting on a doorknob, F = 5 N
The doorknob is located 0.800 m from axis of the frictionless hinges of the door.
The angular acceleration of the dor, a = 2 rad/s²
We need to find the moment of inertia of the door about the hinges.
The person applies a torque to the door and it is given by :
[tex]\tau=Fr[/tex] ...(1)
Also, the torque is equal to :
[tex]\tau=I\alpha[/tex] ...(2)
From equation (1) and (2) we get :
[tex]Fr=I\alpha[/tex]
I is the moment of inertia
[tex]I=\dfrac{Fr}{\alpha }\\\\I=\dfrac{5\times 0.8}{2}\\\\=2\ kgm^2[/tex]
So, the moment of inertia of the door about the hinges is [tex]2\ kgm^2[/tex].
On a smooth horizontal floor, an object slides into a spring which is attached to another mass that is initially stationary. When the spring is most compressed, both objects are moving at the same speed. Ignoring friction, and considering the two masses and spring as a system, what is conserved during this interaction?A) momentum and potential energyB) kinetic energy onlyC) momentum and kinetic energyD) momentum onlyE) momentum and mechanical energy
Answer:
E) momentum and mechanical energy
Explanation:
In the context, an object is attached to the another mass with a spring which is initially at a rest position. Now when the spring is compressed, the two masses moves with the same speed. Now since the both the masses combines with the spring to move together they are considered as one system and in this case the momentum and the kinetic energy will be conserved.
The kinetic energy and momentum of the system after collision and the kinetic energy and momentum of the two masses before collision will be constant.
Cars have safety features to protect people during a crash. A bumper is one type of safety feature. Which bumper design do
you think is safer?
a bumper that crumples
a bumper that's rigid
Answer:
Explanation:
second one ??? pls i hope im right
Answer:
A bumper that crumbles (plato)
Explanation:
Find the Acceleration of a car with the mass of 1200kg and a force of 11x10^3 N
Answer:
9.17 m/s²Explanation:
The acceleration of an object given it's mass and the force acting on it can be found by using the formula
[tex]a = \frac{f}{m} \\ [/tex]
f is the force
m is the mass
From the question we have
[tex]a = \frac{11 \times {10}^{3} }{1200} \\ = 9.16666...[/tex]
We have the final answer as
9.17 m/s²Hope this helps you
Which of the following is an example of Newton’s second law of motion?
A.....Catie’s skateboard hits a curb and she falls forward onto the grass.
B.....a tissue and a rock are dropped from a ladder. The rock exerts a greater force when it hits the ground.
C.....a person stands on a chair and pushes down, and the chair pushes upwards on
the person.
D......Tires from a bike push against the road, and the road pushes back.
Answer:
B
Explanation:
Newton’s Second Law of Motion
Newton’s Second Law of Motion states that ‘when an object is acted on by an outside force, the mass of the object equals the strength of the force times the resulting acceleration’.
This can be demonstrated dropping a rock or and tissue at the same time from a ladder. They fall at an equal rate—their acceleration is constant due to the force of gravity acting on them.
The rock's impact will be a much greater force when it hits the ground, because of its greater mass. If you drop the two objects into a dish of water, you can see how different the force of impact for each object was, based on the splash made in the water by each one.
Answer:
b
Explanation:
What total distance did this student travel?
Seems like some of your question is missin
Explanation:
A 1000kg car is moving with a speed of 20m/s. Determine the net work required to move the
vehicle to a speed of 30m/s?
Answer:
250,000 Joules
Explanation:
The work required is the amount of energy added, so the answer is the difference in kinetic energy before and after the acceleration of the car. (The problem doesn't say it's flat where the car is, but well assume it since there is no information about an elevation change that would require us to concern ourselves with potential energy!)
W = E_final - E_initial
= 1/2 m v_final^2 - 1/2 m v_initial^2
= 1/2 m (v_final^2 - v_initial^2)
= 1/2 (1000 kg) ( (30 m/s)^2 - (20 m/s^2) )
= 1/2 (1000 kg) (500 m^2/s^2)
= 250,000 kg m^2/s^2
= 250,000 Joules
What is the definition of kepal law
Consider a polymer formed by a chain process. By how much does the kinetic chain length change if the concentration of initiator decreases by a factor of 10.0 and the concentration of monomer increases by a factor of 5.0?
Which of the following scenarios best describes Newton's law of action-reaction?
F A bottle of soda sitting in the console of a vehicle appears to move left as the vehicle makes a sharp
right turn.
A rocket moves upward as the engine pushes downward against exhaust gases and the exhaust gases
push upward against the engine.
H
A train traveling 88 kilometers per hour takes approximately one mile to come to a complete stop.
J
An ice skater sharpens the blades of their skates to lessen the effect of friction.
A rocket moves upward as the engine pushes downward against exhaust gases and the exhaust gases push upward against the engine.
You used measurements of distance and time to find velocity. When you calculate the uncertainty on your measurements of time, what units will that uncertainty have?a. counts/time b. time^2 c. time d. time/counts
Answer:
C
Explanation:
The uncertainty will carry the unit of time because it's the time in itself that has error, and not the distance, nor the velocity.
Had it been the uncertainty was to the velocity, then we would say both the unit of the distance and that of the time would have been affected. But as it stands, only that of time will be affected.
how was the theory of plate tectonics developed?
Answer:
Plate tectonic theory began in 1915, when Alfred Wegener developed his "continental drift" idea. Wegener believed that continents plowed through ocean basin crust, explaining why many coasts (such as those in South America and Africa) appear to fit together like a puzzle.
A particle moves along the x axis. It is initially at the position 0.180 m, moving with velocity 0.060 m/s and acceleration -0.380 m/s^2. Suppose it moves with constant acceleration for 3.80 s.
Required:
a. Find the position of the particle after this time.
b. Find its velocity at the end of this time interval.
Answer:
a
[tex]x_2 = -2.3356[/tex]
b
[tex]v = -1.384 \ m/s[/tex]
Explanation:
From the question we are told that
The initial position of the particle is [tex]x_1 = 0.180 \ m[/tex]
The initial velocity of the particle is [tex]u = 0.060 \ m/s[/tex]
The acceleration is [tex]a = -0.380 \ m/s^2[/tex]
The time duration is [tex]t = 3.80 \ s[/tex]
Generally from kinematic equation
[tex]v = u + at[/tex]
=> [tex]v = 0.060 + (-0.380 * 3.80)[/tex]
=> [tex]v = -1.384 \ m/s[/tex]
Generally from kinematic equation
[tex]v^2 = u^2 + 2as[/tex]
Here s is the distance covered by the particle, so
[tex](-1.384)^2 = (0.060)^2 + 2(-0.380)* s[/tex]
=> [tex]s = -2.5156 \ m[/tex]
Generally the final position of the particle is
[tex]x_2 = x_1 + s[/tex]
=> [tex]x_2 = 0.180 + (-2.5156)[/tex]
=> [tex]x_2 = -2.3356[/tex]
You are currently getting 26 sales opportunities per day and closing 64% of them. How many sale opportunists per day?
Answer: 16
Explanation:
a. An object weighs 7.84 N when it is in air and 6.86 N when it is immersed in water. What is the specific gravity of the object?
b. How much pressure does it take for a pump to supply a drinking fountainwith 300 kPa, if the fountain is 30.0 m above the pump?
Answer:
a
[tex]W_s = 8[/tex]
b
[tex]P = 594 000 \ Pa[/tex]
Explanation:
Considering question a
From the question we are told that
The weight of the object in air is [tex]W_1 = 7.84 \ N[/tex]
The weight of the object in water is [tex]W_2 = 6.86\ N[/tex]
Generally the specific gravity of the object is mathematically represented as
[tex]W_s = \frac{W_1 }{W_1 - W_2 }[/tex]
=> [tex]W_s = \frac{7.84}{7.84 -6.86 }[/tex]
=> [tex]W_s = 8[/tex]
Considering question b
From the question we are told that
The pressure required is [tex]P_r = 300 \ kPa = 300 *10^{3} \ Pa[/tex]
The height is [tex]h = 30.0 \ m[/tex]
Generally the pressure require to get the water to the given height is mathematically represented as
[tex]P_h = \rho * g * h[/tex]
Here [tex]\rho[/tex] is the density of water with value [tex]\rho = 1000 \ kg / m^3[/tex]
So
[tex]P_h = 1000 * 9.8 * 30[/tex]
=> [tex]P_h = 294000 \ Pa[/tex]
Generally the pressure require to pump the water to the given height at the require pressure is mathematically represented as
[tex]P = P_h + P_r[/tex]
=> [tex]P = 294000 + 300*10^{3}[/tex]
=> [tex]P = 594 000 \ Pa[/tex]
The second floor of a house is 6 m above the street level. How much work is required to lift a 300-kg refrigerator to the second-story level?
Answer:
Work done, W = 18 kJ
Explanation:
Given that,
The mass of a refrigerator, m = 300 kg
The second floor of a house is 6 m above the street level.
We need to find the work required to lift the refrigerator to the second-story level.
Work done, W = F × d
Putting all the values,
W = 300 × 10 × 6
W = 18000 J
or
W = 18 kJ
So, 18 kJ of work is done in lifting the refrigerator to the second-story level.
What is a physical combination of two or more substances that are blended together without forming a new substance?
Answer:
It is called a mixture.
Explanation:
A mixture is a physical combination of 2 or more substances that are blended together without forming a new substance.
A car traveling 13 m/s to the north collides with a car traveling 19 m/s to the
south. Each car has a mass of 1250 kg. If the system is defined as the two
cars, what is the change in momentum of the system due to the collision?
A. 0 kg*m/s
B. 40,000 kg*m/s
O c. 16,250 kg-m/s
D. 23,750 kg-m/s
Answer: 0kg(m/s)
Explanation:
Humpback whales sometimes catch fish by swimming rapidly in a circle, blowing a curtain of bubbles that confuses a school of fish and traps it in a small area, where the whales can easily catch and eat them. Suppose a 25,000-kg humpback whale swims at 2.0 m/s in a circle of radius 8.2 m. What centripetal force must the whale generate?
Answer:
1.2 x [tex]10^4[/tex] N
Explanation:
The centripetal force of a body moving in a circle is given by:
Centripetal force = [tex]\frac{Mv^2}{r}[/tex]
where M = mass of the object, v = velocity with which the object is moving, and r = radius of the circle.
In this case, M = 25,000 kg, v = 2.0 m/s, and r = 8.2 m. Hence;
Centripetal force generated by the whale = 25,000 x 2^2/8.2
= 12,195.12 N = 1.2 x [tex]10^4[/tex] N to two significant digits.
what is the correct term for the people who came before us?
Answer:
Ancestors!
Explanation:
I know a thing or two~
Answer:
It depends on what the context is, if you mean people that came long before us you might be refering to ancestors, but if you mean people that came before us at any time then you would be refering to a predecessor.
Explanation:
Why do you think the objects in each collision experience a different change in velocity?
Answer:
In a collision, there is a collision force which endures for some amount of time to cause an impulse. This impulse acts upon the object to change its velocity and thus its momentum
1. Find the period of a tuning fork that vibrates 120 times/sec.?? I will give brainlest
Answer:
it the last one
Explanation:
At standard temperature and pressure, carbon dioxide has a density of 1.98 kg/m3. What volume does 1.70 kg of carbon dioxide occupy at standard temperature and pressure?
Answer:
volume= 0.85m^3Explanation:
The density of a substance is defined as the mass per unit volume of the substance, the unit is in kg/m^3 and it is represented by the greek letter rho
Step one:
given data
we are told that the density of Co2= 1.98 kg/m3
and the mass of Co2 is= 1.70 kg
we know the relation between mass, volume and density is
[tex]density=mass/volume[/tex]
make volume subject of formula we have
[tex]volume=mass/density[/tex]
substitute we have
[tex]volume=1.7/1.98\\\\volume= 0.85m^3[/tex]
How is energy that is stored in food released?
A- atoms increase in movement
B- atoms are split
C- heat is released
D-chemical bonds in fats are proteins are broken
Answer:
i think its A
Explanation:
Answer:
D
Explanation:
The chemical energy stored in food is released by cells through the process of respiration. (cellular respiration)
This stored energy is released whenever these chemical bonds are broken in metabolic processes such as cellular respiration. Cellular respiration is the process by which the chemical energy of “food” molecules is released and partially captured in the form of ATP.
23)
What statement BEST describes a gas?
A)
Gases have definite shape and variable volume.
B)
Gases have variable shape and variable volume.
0
Gases have a definite shape and definite volume.
D)
Gases have a variable shape and definite volume.
Answer:
b
Explanation:
What is inertia?
An object's tendency to move quicker
An object's tendency to change direction
An object's tendency to resist changes in motion
An unbalanced force on an object
Answer:
I think the answer should be an object's tendency to resist changes in motion.
Explanation:
Inertia is resistance of any physical object to any changes in its velocity.
Answer:
an object's tendency to resist changes in motion.
Explanation:
Anuja is holding a stuffed dog, with a mass of 0.30 kg, when Derek decides that he wants it and tries to pull it away from Abuja. If Derek pulls horizontally on the dog with a force of 10.0 N and Anudja pulls with a horizontal force of 11.0 N, what is the horizontal acceleration of the dog?
Answer:
a = 3.33 m/s²
Explanation:
The horizontal acceleration of the dog can be found by using Newton's Second Law of Motion as follows:
F = ma
where,
F = Unbalanced force applied on the dog = 11 N - 10 N = 1 N
m = mass of the dog = 0.3 kg
a = horizontal acceleration of dog = ?
Therefore,
1 N = 0.3 kg(a)
a = 1 N/0.3 kg
a = 3.33 m/s²
A vector B , with a magnitude of 8.0 m, is added to a vector A , which lies along an x axis. The sum of these two vectors is a third vector that lies along the y axis and has a magnitude that is twice the magnitude of A . What is the magnitude of A?
Answer:
the magnitude of A is 3.577
Explanation:
According to the question it is given that there is a magnitude of 8.0 m that added to the vector A that lies on x axis also the sum of two vectors would be third vector by considering the y axis and the magnitude is the twice of the magnitude B
The computation of the magnitude of A is shown below:
[tex]A \hat{i} + B = 2A \hat{j}\\\\A \hat{i} + 8 = 2A \hat{j}\\\\8 = 2A \hat{j} - A \hat{i}\\\\\mid8\mid = \sqrt{(2A \hat{j})^2 + (- A \hat{i})^2} \\\\8 = \sqrt{5A} \\\\A = \frac{8}{\sqrt{5} }[/tex]
A = 3.577
Hence, the magnitude of A is 3.577