A roller coaster moving along its track rolls into a circular loop of radius r. In the loop, it is only affected by its initial velocity, gravity, and the shape of the track. Let v denote the instantaneous speed and a denote the magnitude of the instantaneous acceleration of the roller coaster in the loop. Which of the following is true in the loop?
a. The roller coaster is not in uniform circular motion, but we still have a=v^2/r everywhere on the loop
b. The roller coaster is not in uniform circular motion, but the tangential acceleration is so small that we can approximate a by v^2/r everywhere on the loop
c. The roller coaster is in uniform circular motion
d. The roller coaster is not in uniform circular motion, and a=v^2/r is only applicable at the very top and bottom of the loop where the tangential acceleration vanishes
Answer:
c. The roller coaster is in uniform circular motion
Explanation:
Since the loop is circular with radius r, and its instantaneous speed, v is always constant, and also, its centripetal acceleration, a' = v²/r.
Since the angular speed, ω = v/r does not change, the magnitude of its tangential acceleration is zero although there is a change in its direction because the direction of its initial velocity changes. That is a" = rα and α = Δω/Δt since Δω = 0, α = 0 and a" = r(0) = 0
So, there is no tangential acceleration. Since there is no tangential acceleration, our instantaneous acceleration which is the vector sum of our centripetal acceleration and tangential acceleration is a = √(a'² + a"²) = √(a'² + 0²) = √a'² = a' = v²/r
So, a is always v²/r.
Since the instantaneous acceleration is always (a = v²/r) constant, the motion is uniform. So, it is uniform circular motion.
The roller coaster is not in uniform circular motion, and [tex]a = \frac{v^2}{r}[/tex] is only applicable at the very top and bottom of the loop where the tangential acceleration vanishes.
The given parameters;
radius of the circular path, = r instantaneous speed = v instantaneous acceleration = aThe motion tension on the loop at the lowest point in the circular motion is given as;
[tex]T = mg + \frac{mv^2}{r}[/tex]
The motion tension on the loop at the highest point in the circular motion is given as;
[tex]T = \frac{mv^2}{r} - mg[/tex]
This shows that circular motion is affected by;
acceleration due to gravity, gradius of the circular path, rspeed of the motion, vmass of the object, mThus, we can that the roller coaster is not in uniform circular motion, and [tex]a = \frac{v^2}{r}[/tex] is only applicable at the very top and bottom of the loop where the tangential acceleration vanishes.
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Which of the following statements are TRUE about nonmetals?
SELECT ALL THAT APPLY
a They can exist as solids, liquids, or gases
b
They have a wide variety of properties, most of
which are the opposite of metals.
С
They tend to have higher melting points than
metals.
d
They make up the majority of the periodic table of
elements
Answer:
c
Explanation:
The statement that are true regarding nonmetals are that they can exist as solids, liquids, or gases, have a wide variety of properties, most of which are the opposite of metals. The correct options are a and b.
What are nonmetals?Non-metals are naturally occurring materials that do not generate heat or electricity and are structurally brittle.
Non-metallic elements in the periodic table include hydrogen, carbon, nitrogen, oxygen, phosphorus, arsenic, and selenium.
Metals make up the majority of the elements on the periodic table. Depending on how the artificially synthesized elements are classified, approximately 93 elements are metals. Only about 18 elements are considered nonmetals.
Because most metals have high melting points, they are solid at room temperature. At room temperature, most nonmetals have low melting points because they are not solid.
Nonmetals can exist as solids, liquids, or gases and have a wide range of properties, the majority of which are diametrically opposed to metals.
Thus, the correct options are a and b.
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Starting from the front door of your ranch house, you walk 55.0 m due east to your windmill, turn around, and then slowly walk 35.0 m west to a bench, where you sit and watch the sunrise. It takes you 30.0 s to walk from your house to the windmill and then 36.0 s to walk from the windmill to the bench.
Required:
a. For the entire trip from your front door to the bench, what is your average velocity?
b. For the entire trip from your front door to the bench, what is your average speed?
Answer:
Explanation:
Average velocity = Total displacement / total time
Average speed = total distance covered / total time
a )
For the entire trip from your front door to the bench
Total displacement = 55 - 35 = 20 m [ first displacement is positive and second displacement is negative , because second displacement is in opposite direction ]
Total displacement = 20 m
Total time = 30 + 36 = 66 s
Average velocity = 20 / 66
= .303 m / s
b )
For the entire trip from your front door to the bench
Total distance covered = 55 + 35 = 90 m
Total time = 30 + 36 = 66 s
Average speed = 90 / 66
= 1.36 m / s
I NEED HELP ASAP I WILL GIVE BRAINLIEST ITS DUE TODAY
Decribe how to combine equal forces acting in opposite directions
Answer:
If the two forces are acting in opposite directions, you subtract one from the other. Think of it this way: if one force acts in the opposite direction from another, then it is applying a negative force in that direction. What happens when a negative is added to a positive? Subtraction. If the magnitudes of the forces are equal, they will cancel out.
The electron gun in an old TV picture tube accelerates electrons between two parallel plates 1.3 cm apart with a 21 kV potential difference between them. The electrons enter through a small hole in the negative plate, accelerate, then exit through a small hole in the positive plate. Assume that the holes are small enough not to affect the electric field or potential.
Required:
a. What is the electric field strength between the plates?
b. With what speed does an electron exit the electron gun if its entry speed is close to zero?
Answer:
a. Electric field strength is 1.6*10^6 V/m = 1.6 Megavolt/meter
b. speed of an electron is 5.2*10^14m/s
Explanation:
The electric field strength is given by:
E = ΔV/d
E = electric field strength,
ΔV = potential difference,
d = plate spacin
ΔV = 21×10^3V, d = 1.3×10^-2m
a) E = V / d = (21*10^3)/(1.3×10^-2) = 1.6*10^6 V/m = 1.6 Megavolt/meter
b) Exit energy = V . e
Where 'e' is the charge of electron (1.6 * 10^(-19)
Exit energy = (21*10^3)*(1.6*10^-19) = 3.36*10−15
From the above, speed v = √2*Exit Energy/mass
Where 'm' is the mass of electron (9.1 * 10^(-31)
v = √2*energy/mass
v = √2*(3.36*10^-15)/(9.1*10^-31) = 5.2*10^14m/s
Calculate the heat energy required to increase the temperature of 3 kg of water by 20ºC. The specific heat capacity of water is 4200 J/ kg °C
Answer:
Heat energy required = 252000J or 252KJ.
Explanation:
Given the following data;
Mass = 3kg
Temperature = 20ºC
Specific heat capacity of water = 4200 J/kg°C
To find the heat energy required;
Heat capacity is given by the formula;
[tex] Q = mct [/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. t represents the temperature.Substituting into the equation, we have;
[tex] Q = 3*4200*20 [/tex]
Q = 252000 Joules or 252 Kilojoules.
A long, straight wire has a uniform constant charge with linear charge density, - 3.60 nC/m. The wire is surrounded by a long nonconducting, thin-walled cylindrical shell that is charged on its outside surface, such that the electric field outside the shell is zero. The shell has a radius of 1.50 cm.
Required:
What uniform area charge density rho is needed on the shell for the electric field to be zero outside the shell?
Answer:
Uniform area charge density rho is needed is 3.82*10^-8 C.m^-2
Explanation:
See the attached files.
To find the rho, I used Gauss law for cylindrical shell which is equation 1 and Gauss law for the rod which is equation 4.
Note that in equation 4, Lamda is the charge per length while L is the length if the rod. Also R is the radius of the shell.
The final answer is 3.82*10^-8 C.m^-2 which is the uniform area charge density rho is needed.
A certain green light bulb emits at a single wavelength of 550 nm. It consumes 55 W of electrical power and is 75% efficient in converting electrical energy into light. (a) How many photons does the bulb emit in one hour? (b) Assuming the emitted photons to be distributed uniformly in space, how many photons per second strike a 10 cm by 10 cm paper held facing the bulb at a distance of 1.0 m?
Answer:
a) #_total = 4 10²³ photons / h, b) # _photon_area = 3 10²² photons
Explanation:
a) Let's start by calculating the energy of an emitted photon
E₀ = h f
c = λ f
substituting
E₀ = h c /λ
E₀ = [tex]\frac{6.62 \ 10^{-34} \ 3 \ 10^{8} }{550 \ 10^{9} }[/tex]
E₀ = 3.6 10⁻¹⁹ J
Let's use a direct proportion rule (res rule) if a photon has Eo, how many photons are there in 55W
#_foton = 55 / E₀
# _photon = 55 / 3.6 10⁻¹⁹ = 15.27 10¹⁹ photons
This version is with 100% if the conversion is 75%, how many footnes are there
#_foton_real = # _foton 75/100
#real_photon = 15.27 10¹⁹ 0.75
# _real_photon = 11.45 10¹⁹ photons
this is the broadcast in a second
#_total = # _real_photon t
#_total = 11.45 10¹⁹ 3600
#_total = 4.1 10²³ photons / h
#_total = 4 10²³ photons / h
b) This number of photons is constant, so after being emitted they are distributed on the surface of a sphere, in this case of radius r = 1.0 m
the volume of a sphere is
A = 4π r²
A = 4π 1²
A = 12,566 m²
the area of the plate is
A₁ = l₁ l₂
A₁ = 0.10 0.10
A₁ = 1 10⁻² m
Let's use a direct proportion rule, if there are 4.1 10²³ photons in an area A, how much are there in an area A₁
# _photon_area = #_total A₁ / A
# _photon_area = [tex]4.1 \ 10^{23} \ \frac{1 \ 10^{-2} }{12.566}[/tex]
# _photon_area = 3.26 10²²
as the number of photons must be a whole number
# _photon_area = 3 10²² photons
A car of mass 150 kg is riding down at constant velocity. What is the normal force?
The formula is ( Fg=mg ; Fnet =ma ; Fx = Fcos theta ; Fy = Fsin theta)
Answer and I will give you brainiliest
Answer:
1500N
Explanation:
Normal force = mg - F sin theta
constant velocity means acceleration = 0
F= ma = 150× 0 = 0N
thus;
normal force = mg = 150 × 10 = 1500N
Answer:
864N
Explanation:
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A female cheetah left her cubs to hunt for food. She sprinted 30 m away from her den in two seconds. Next, she turned around and traveled 10 meters back toward her den in three seconds. She suddenly stopped and listened intently for 1 second. Then, she traveled 40 meters away from her den in four seconds.
What is the average velocity in m/s ?
please need help hurry
Answer:
6 m/s
Explanation:
Recall that average velocity is the quantity final position minus initial position, divided by the time it took. So in our case, the cheetah after all the away and back and away again, the mother got a total of: 30 - 10 + 40 = 60 m
and the total time is: 2 + 3 + 1 + 4 = 10 second
Then the average velocity is: 60 m / 10 sec = 6 m/s
Newton's second law says that when an___force is applied to a___ it causes it to____
Answer:
Newton's second law says that when an unbalanced force is applied to a mass it causes it to accelerate
Explanation:
Which one of the following statements is true concerning the magnitude of the electric field at a point in space? It is a measure of the electric force on any charged object. It is a measure of the ratio of the charge on an object to its mass. It is a measure of the electric force per unit mass on a test charge. It is a measure of the electric force per unit charge on a test charge. It is a measure of the total charge on the object.
Answer:
It is a measure of the electric force per unit charge on a test charge.
Explanation:
The magnitude of the electric field is defined as the force per charge on the test charge.
Since we define electric field as the force per charge, it will have the units of force divided by the unit of charge. This implies that the SI unit of electric field is given as Newton/Coulomb (N/C).
Because from the definition of the electric field intensity, it can be defined as force per unit charge. The correct answer is option D
ELECTRIC FIELDElectric field is the region of space where electric force can be felt. It can also be expressed as electric field intensity E. Mathematically, it can be expressed as;
E = F/q or E = V/d
From the question, the statements that is true concerning the magnitude of the electric field at a point in space is " It is a measure of the electric force per unit charge on a test charge "
Because from the definition of the electric field intensity, is can be defined as force per unit charge.
Therefore, option D is the right answer.
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A 7400 kg rocket blasts off vertically from the launch pad with a constant upward acceleration of 2.35 m/s^2 and feels no appreciable air resistance. When it has reached a height of 585 mm, its engines suddenly fail so that the only force acting on it is now gravity.
Required:
a. What is the maximum height this rocket will reach above the launch pad?
b. How much time will elapse after engine failure before the rocket comes crashing down to the launch pad, and how fast will it be moving just before it crashes?
c. Sketch ayât,,vyâât, and y - t graphs of the rocketâs motion from the instant of blast-off to the instant just before it strikes the launch pad.
Answer:
Explanation:
Let us first calculate the velocity of rocket on reaching the height of 585 m
v² = u² + 2 a s
= 0 + 2 x 2.35 x 585
v = 52.43 m /s
For onward journey of rocket , initial velocity u = 52.43 m /s , acceleration = - g = - 9.8 m /s² final velocity at top point v = 0
v² = u² - 2gh
0 = 52.43² - 2 x 9.8 x h
h = 140.25 m
Total height reached
= 585 + 140.25
= 725.25 m
b )
Time to reach the top position be t₁
v = u - gt₁
0 = 52.43 - 9.8 t₁
t₁ = 5.35 s
Time to reach the ground after reaching highest point be t₂
h = ut + 1/2 g t²
u = 0 as at top point , velocity = 0
725.25 = 0 + .5 x 9.8 t₂²
t₂² = 148
t₂ = 12.16 s
Total time = t₁ + t₂
= 5.35 + 12.16
= 17.51 s .
A point charge of -11 [Coulombs] is placed inside a spherical conducting shell with net charge of 5 [Coulombs]. Calculate the net charge on the outer surface of the conducting shell. Enter your answer without units (example 100 for 100 [Coulombs] or -100 for -100 [Coulombs] ).
Answer:
20 C
Explanation:
To do this, is pretty easy, we just need to do a little reasoning of what is happening.
When any charge called q is placed inside this metallic shell which is spheric, all the opposite and even equal charges are induced on the inner and outer surface of the shell. Hence, we can say that if in the inner shell we have +q, in the outer will be -q.
Now, here we have the shell with 5 C, and when the charge of -11 C is placed inside the shell we can have the following changes on the inner surface and the outer surface:
Inner surface: +11 C
Outer surface: 9 + 11 = 20 C
Net charge on the outer surface: 20 CHope this helps
Which statement BEST explains why a bouncing basketball will not remain in motion forever?
Group of answer choices
The energy is transferred to sound and heat energy.
The energy is used up and destroyed.
The energy is transferred to light and potential energy.
The energy is transferred to chemical and heat energy.
Answer:
The energy is transferred to chemical and heat energy.
Explanation:
If you define "bouncing" as leaving the ground for any amount of time, the ball stops bouncing when the elastic energy stored in the compression phase of the bounce is not enough to overcome the weight of the ball. This is the proof of the answer i Hope this helps :)
How will the plants that grow from a plant fertilized seeds compare to the plants grown from its daughter tubers?
Answer:
A
Explanation:
the answer would be basicly A
For each picture below identify the material and closing the sandwich as transparent translucent or opaque
1)
Which of the following objects has the greatest inertia?
A)
Pencil
B)
Ping pong ball
C)
Baseball
Bowling ball
Answer:
the answer is C baseball and bowling ball
A spring has a spring constant of 25 Newtons per meter. The minimum force required to
stretch the spring 0.20 meter from its equilibrium position is approximately
Answer:
6.3N
Explanation:
Guessed it right on castle learning
Answer:
6.3 N
Explanation:
F=kx
F=(25N/m)(0.25m)
6.3 N
Sound waves are what type of energy wave?
A. mechanical
B. longitudinal
C. transverse
Answer:
mechanical wave
Explanation:
The sound vibrations cause waves of pressure that travel through a medium, such as air, water, wood or metal. Sound energy is a form of mechanical energy
Answer:
A mechanical waves
Explanation:
in nature include water waves, sound waves, seismic waves and internal water waves
A bobsled accelerates from rest at a constant rate of 2 m/s2. How fast is it going after 3.5 seconds
Answer:
7m/s
Explanation:
Using the equation of motion;
v = u+at
u = 0m/s
t = 3.5secs
a = 2m/s^2
Get the required velocity
v = 0 + 2(3.5)
v = 2(3.5)
v = 7.0m/s
Hence the body is moving with a speed of 7m/s
before:
2m
What is the change in momentum if the v before = 1m/s and the velocity after = 1m/s?
(Change in momentum - momentum after-
after:
2m
momentum before) p - mv
Answer:
22
Explanation:
before:
2m
What is the change in momentum if the v before = 1m/s and the velocity after = 1m/s?
(Change in momentum - momentum after-
after:
2m
momentum before) p - mv
please help
What variables have the most effect on the strength of the gravitational attraction between two
massive objects?
Answer:
Newton's law also states that the strength of gravity between any two objects depends on two factors: the masses of the objects and the distance between them. Objects with greater mass have a stronger force of gravity between them.
The gravitational force depends upon two variables the mass of the objects and the distance between them.
What is gravitational force?In the universe, each body attracts another body towards itself is called Gravitational Force. Thus, gravitation is the study of the interaction forces between two masses.
Newton’s law of gravitation can be defined as every system of matter in the universe attracts every other system with a definite force. The magnitude of this force has a direct relationship with the masses of the systems.
[tex]F \propto M_1M_2[/tex]
The magnitude of this force has an inverse relation with the square of the distance.
[tex]F \propto 1/r^2[/tex]
Therefore, the gravitational attraction between two bodies can be represented as:
[tex]\displaystyle F = G\frac{ M_1M_2}{r^2}[/tex]
The mass of the physical system is directly proportional to the gravitational attraction therefore when the mass increases then the gravitational force will increase.
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A river flows at 2m/s the velociy of ferry relative to the shore is 4m/s
Answer:
Explanation:
.....
A 7.80-g bullet moving at 600 m/s strikes the hand of a superhero, causing the hand to move 5.90 cm in the direction of the bullet's velocity before stopping. (a) Use work and energy considerations to find the average force that stops the bullet. N (b) Assuming the force is constant, determine how much time elapses between the moment the bullet strikes the hand and the moment it stops moving. s
Answer:
a) F = 2.3797 10⁴ N, b) t = 1.97 10⁻⁴ s
Explanation:
a) For this exercise let's use the relationship between work and scientific energy
W = ΔK
W = F .d
ΔK = ½ m v² - ½ m v₀²
the bold are vectors. in this case the force of the bullet on the hand and the displacement of the bullet has the opposite direction, therefore the angle between the two is 180. The velocity when the bullet stops is zero.
We substitute
-F x = - ½ m vo2
F = [tex]\frac{m v_o^2}{2 x}[/tex]
let's calculate
F = [tex]\frac{7.80 \ 10^{-3} 600^{2} }{2 \ 5.90 \ 10^{-2} }[/tex]
F = 2.3797 10⁴ N
b) let's find the acceleration
F = ma
a = F / m
a = 2.3797 10⁴ / 7.80 10⁻³
a = 3.05 10⁶ m / s²
now we can use the kinematics relations
v = v₀ - a t
the final velocity is zero v = 0
t = v₀ / a
t = 600 / 3.05 10⁶
t = 1.97 10⁻⁴ s
Calculate the net force on the crate if the magnitude of the forces in the diagram are Fg=10N, Fapp= 7.5N, Ff=2.5N and Fn=10N
Answer:
5 units to the left
Explanation:
I had the same question :)
The two most prominent wavelengths in the light emitted by a hydrogen discharge lamp are 656 nm (red) and 486 nm (blue). Light from a hydrogen lamp illuminates a diffraction grating with 520 lines/mm , and the light is observed on a screen 1.4 m behind the grating.
Required:
What is the distance between the first-order red and blue fringes?
Answer:
0.143 m
Explanation:
Since
d = 1/N = 1/520 = 1.92 * 10^-3 mm
For red light;
θ = sin^-1 (1 * λred/d) = sin^-1 (1 * 656 * 10^-9/1.92 * 10^-6) = 19.98°
L = 1.4 * (tan 19.98) = 0.509 m
For blue light;
θ = sin^-1 (1 * λblue/d) = sin^-1 (1 * 486 * 10^-9/1.92 * 10^-6) = 14.66°
L = 1.4 * (tan 14.66°) = 0.366 m
Distance between the first-order red and blue fringes= 0.509 m - 0.366 m = 0.143 m
Two white rabbits produce a brown rabbit. How is this possible? Explain
Answer:
If one of the parents is white and the other is brown, their offspring will be either white or brown with equal probabilities. Rabbits in this population mate randomly; thus, the probability of mating two white rabbits is the same as the probability of mating between two brown rabbits.
Explanation:
You want to paddle a boat straight across the Mississippi River. You are able to paddle the boat with a speed of 2.2 m/s relative to the water, and the current flows at a speed of 1.1 m/s. In what direction (angle), relative to the river bank, do you need to point the boat to cross the river in the shortest time? The width of the river is 95.0 m.
A) 60 degrees
B) 80 degrees
C) 90 degrees
D) 70 degrees
E) 50 degrees
Answer:
C) 90 degrees
Explanation:
If we could have an imaginative illustration about what the question is all about.
We could think of the velocity of the river (V_r cosθ) as a horizontal component and the velocity of the boat (V_b sinθ) as the vertical component.
So the velocity of the boat V_b = 2.2 m/s; &
the velocity of the river V_r = 1.1 m/s
∴
The minimum time (which is the shortest time) required for the boat to cross the river is θ = 90°
the time require is:
[tex]t = \dfrac{d}{v_b \ sin \theta}[/tex]
[tex]t = \dfrac{95}{2.2}[/tex]
t = 43.18 sec