Answer:
v = 9.04 m / s
Explanation:
For this exercise we can use the relation that the work of the non-conservative force (friction) is equal to the variation of the mechanical energy of the system.
W = Em_f - Em₀ (1)
Starting point. Lower slope
Em₀ = K = ½ m v²
highest point. Where is the skier at a height h
Em_f = U = m g h
The work of rubbing
W = -fr x
the negative sign is because the friction force opposes the movement.
Let's set a reference system where the x axis is parallel to the slope and the y axis is perpendicular
let's use trigonometry to break down the weight
cos θ = W_y / W
sin θ = Wₓ / W
W_y = W cos θ
Wₓ = W sin θ
Y axis
N - Wₓ = 0
N = mg sin θ
X axis
fr = m a
the friction force has the expression
fr = μ N
fr = μ mg sin θ
we look for the job
W = - μ mg sin θ x
where x is the distance along the slope
we substitute in 1
-μ mg sin θ x = mg h - ½ m v²
let's use trigonometry to find the distance x
tan 30 = h / x
x = h / tan 30
we substitute
- [tex]\mu \ mg \ sin \theta \ \frac{h}{tan 30} \ x[/tex] = m gh - ½ m v²
we use
tan 30 = sin30 / cos30
v² = 2g h + 2 μ g h cos 30
v = [tex]\sqrt{ 2gh \ (1+ cos 30}[/tex]
let's calculate
v = [tex]\sqrt{ 2 \ 9.8 \ 4 \ (1 + 0.05 \ cos \ 30)}[/tex]
v = 9.04 m / s
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Answer:
OK we appreciate your concern.
I need help! thank you
Answer:
it is coice A and choice D
ANSWER THIS! Which of these statements about the Sun is the result of its closeness to Earth? A) It is the only star with a gravitational pull. B) It is the largest star in the Milky Way Galaxy. C) It appears (from Earth) to be the brightest star. D) It has the lowest temperature of any star seen from Earth.
Answer:
C) It appears (from Earth) to be the brightest star.
Explanation:
This is because due to sun's brightness we can predict its distance.
is this correct and why
Answer:
correct ooooooooooooo
What are some possible injuries that can occur as a result of anabolic steroid use?
I need help with science o.o:
Question 1:
An egg yolk is unicellular.
True
False
___________________________
Question 2:
Your body has more than a billion cells.
True
False
_____________________
Question 3:
Almost all cells are not microscopic.
True
False
please dont steal my points :>
Answer:
TrueTrueFalseExplanation:
this is the answer
Answer:
1.true
2true
3.false
Explanation:
espero que te ayude
A town requiring 2.0 m3/s of drinking water has two sources, a local well with 15 g/m3 nitrate (as N) and a distant reservoir with 5 g/m3 nitrate (as N). What flow rates of well and reservoir water are needed to meet the EPA drinking water standard and minimize the use of more expensive reservoir water
Explanation:
Drinking water requirement in town 2.0 m^3/s of water per second
nitrate in local well nitrate per 15 [tex]\mathrm{m}^{3}[/tex] of water
nitrate in distant reservoir [tex]=5 \mathrm{~g} / \mathrm{m}^{3}[/tex]
Let the flow rate of well
flow rate of reservoir [tex]=y m^{3} / s[/tex]
Drinking water requirement is [tex]45 \mathrm{ppm}[/tex] or [tex]45 \mathrm{~g} / \mathrm{m}^{3}[/tex]
therefore, the total flow of drinking water
A car's bumper is designed to withstand a 7.20 km/h (2.0 m/s) collision with an immovable object without damage to the body of the car. The bumper cushions the shock by absorbing the force over a distance. Calculate the magnitude of the average force (in N) on a bumper that collapses 0.195 m while bringing a 830 kg car to rest from an initial speed of 2.0 m/s.
Answer:
8512 N
Explanation:
From the work energy theorem we know that: The net work done on a particle equals the change in the particles kinetic energy:
[tex]W=\Delta K=K_{f}-K_{i} \\ \\qquad \begin{array}{r} W=F \cdot d, \Delta K=\frac{1}{2} m v_{f}^{2}-\frac{1}{2} m v_{i}^{2} \\ F \cdot d=\frac{1}{2} m v_{f}^{2}-\frac{1}{2} m v_{i}^{2}[/tex]
Where:
-W is the work done by the force.
- F is the force actin on the.
- d is the distance travelled.
- m is the mass of the car.
- [tex]v_{f}, v_{i}[/tex] are the final and the initial velocity of the car
[tex]K_{f}, K_{i}[/tex] are the final and the kinetic energy of the car.
Givens: [tex]m=830 \mathrm{~kg}, v_{i}=2 \mathrm{~m} / \mathrm{s}, v_{f}=0 \mathrm{~km} / \mathrm{h}, d=0.195 \mathrm{~m}[/tex]
Plugging known information to get:
[tex]F \cdot d &=\frac{1}{2} m v_{f}^{2}-\frac{1}{2} m v_{i}^{2} \\ F &=\frac{\frac{1}{2} m v_{f}^{2}-\frac{1}{2} m v_{i}^{2}}{d} \\ &=\frac{0-\frac{1}{2} \times 830 \times 2^{2}}{0.195} \\ &=8.512 \times 10^{3} \\ F &=8.512 \times 10^{3} \mathrm{~N}[/tex]
A sinusoidal wave is reflected at the surface of a medium whose properties are such that half the incident energy is absorbed. Consider the field that results from the superposition of the incident and the reflected wave. An observer stationed somewhere in this field finds the local electric field oscillating with a certain amplitude E. What is the ratio of the largest such amplitude noted by an observer to the smallest amplitude noted by any observer
Answer:
[tex]\frac{Ei + Er}{Ei-Er}[/tex]
Explanation:
Ratio of the largest amplitude to the smallest amplitude is called voltage standing wave ratio ( along a transmission line )
Determine the ratio of the largest such amplitude noted by an observer tot the smallest amplitude
Expression for VSWR
VSWR = [tex]\frac{1 + \sqrt{\frac{Pr}{Pi} } }{1 - \sqrt{\frac{Pr}{Pi} } }[/tex] where ; Pr = reflected power , Pi = Incident power
hence the ratio of the largest amplitude to the smallest amplitude
= [tex]\frac{Emax}{Emin}[/tex] = [tex]\frac{Ei + Er}{Ei-Er}[/tex] where ; Ei = amplitude of incident wave, Er = amplitude of reflected wave
Please Help!!!!!
Belinda observes that the reaction 2H2O+O2=2H2O2 appears to have stopped, because the concentrations of reactants and products are not changing. Which statement is true at this point in the reaction
A P E X
Answer: Molecules of H202, H20 and 02 are still forming. ( A P E X )
Explanation: I know this is late but for anyone looking at this later
The above question is incomplete, I think the original question is
Belinda observes that the reaction 2H20+02 2H2O2 appears to have stopped because the concentrations of reactants and products are not changing. Which statement is true at this point in the reaction?
A. Molecules of H₂O₂ are formed only when the reaction vessel is disturbed.
B. Molecules of H2O2 have stopped forming.
C. Molecules of H20 and O₂ have stopped forming.
D. Molecules of H2O2, H2O, and O2 are still forming.
At this point in the reaction, the system has reached a state of equilibrium i.e there is no net change in the concentrations of reactants and products. So the Molecules of H2O2 have stopped forming. The correct option is B.
What is the state of equilibrium?In chemistry, a state of equilibrium refers to a situation where the concentrations of reactants and products in a chemical reaction are no longer changing over time.
This occurs when the rates of the forward and reverse reactions are equal, and there is no net change in the concentrations of reactants and products.
At equilibrium, the system is in a dynamic state, where the forward and reverse reactions continue to occur, but at the same rate, resulting in no overall change in the concentrations of the species involved in the reaction. The equilibrium state is typically characterized by the equilibrium constant, which is a measure of the relative concentrations of reactants and products at equilibrium for a given reaction under specific conditions of temperature, pressure, and concentration.
Here in this question,
The molecules of H2O2 have stopped forming. This means that the forward reaction (2H2O + O2 → 2H2O2) and the reverse reaction (2H2O2 → 2H2O + O2) are occurring at the same rate, resulting in no net change in the concentration of H2O2. However, molecules of H2O and O2 are still being consumed and produced as they are involved in the reaction, but their concentrations are not changing because they are being replenished at the same rate that they are being consumed.
Therefore, the correct answer is B i.e Molecules of H2O2 have stopped forming.
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A thermionic tube with only a cathode and an anode is called?
A submarine is 309 m horizontally from the shore of a freshwater lake and 105 m beneath the surface of the water. A laser beam is sent from the submarine so that the beam strikes the surface of the water 227 m from the shore. A building stands on the shore, and the laser beam hits a target at the top of the building. The goal is to find the height of the target above sea level.
Required:
a. Draw a diagram of the situation, Identifying the two triangles that are important in finding the solution.
b. Find the angle of incidence of the beam striking the water-air interface.
c. Find the angle of refraction.
d. What angle does the refracted beam make with the horizontal?
e. Find the height of the target above sea level.
Answer:
Explanation:
a) See the attached file for diagram . The two triangles are ABC and DEC .
b )
Angle of incidence = i
Tan i = ( 309 - 227 ) / 105
= 82 / 105 = .78
i = 38°
c )
Sin i / sinr = 1 / μ where μ is refractive index of water .
Sin i / sinr = 1 / μ = 1 / 1.33
sin 38 / sinr = .7518
.6156 / sinr = .7518
sinr = .6156 / .7518
.819
r = 55°
d )
angle the refracted beam makes with the horizontal = 90 - 55 = 35°
e )
h / 227 = Tan 35
h = 227 x Tan 35
= 159 m
Height required = 159 m .
a mid-oceanic might be compared to what continental landform
Answer:
mountain range:)
Explanation:
If the delay of the 10-bit adder is 1ns, the setup time, the hold time, and the propagation delay of the registers is 0.3 ns, 0.1 ns, and 0.2 ns, respectively. The minimum cycle time is ns_____.
Answer:
1.6 ns
Explanation:
Given data :
delay in 10-bit adder = 1ns
setup time = 0.3 ns
hold time = 0.1 ns
propagation delay = 0.2 ns
calculate the minimum cycle time
∑ delay + setup time + hold time + propagation delay
= 1 + 0.3 + 0.1 + 0.2
= 1.6 ns
Which of the following involves an endothermic reaction
Answer:
A
Explanation:
Photosynthesis requires energy to drive the chemical reaction. Photosynthesis is an endothermic reaction. This means it cannot occur without energy (from the Sun).
describe the relationship of the atoms shown above
choices:
Answer:
I don't know.
The diagram below shows the beaks of five species of birds that developed over time from
one parent species. The five species of birds can be found living in the different areas. Which
of the following BEST explains why the beak shape of each species of bird developed
differently? * 5
(1 Point)
A. Birds in different areas were able to make different birdcalls and songs.
O
B. Birds in different areas were exposed to different food sources.
C. Birds in different areas had different materials to make nests.
o o
D. Birds in different areas had different predators to defend or hide from.
Answer:
Birds in different areas were exposed to different food sources.
Explanation:Im almost 100 percent this is it.
Answer:
the answer is B
Explanation:
i did test on preformance
Need this homework for today so help 50 point
Select the correct answer.
Which theory was first proposed by Albert Einstein?
OA. the theory of special relativity
O B. the theory of universal gravitation
c. the theory of inertia
OD. the theory of radioactivity
Answer:
A. the theory of special relativity.
Explanation:
The theory of special relativity was first proposed theory by Albert Einstein.
Hope it will help :)❤
PLZZZ HELP!!! 80PTS!!!
You are given a toy car and told it has a density of 0.54 g/mL and a volume of 38.2 mL. Calculate impulse, given that the toy car's acceleration is 10 m/s^2 and time is 10 s. WRITE THE NUMBER ONLY and DO NOT ROUND.
Answer:
Impulse = [tex]206.28 * 10 = 2062.8[/tex] g.m/s
Explanation:
Impulse is equal to the product of force and time
Here
Density of car = [tex]0.54[/tex] g/mL
Volume of car [tex]= 38.2[/tex] mL
Mass of the car is equal to the product of density and volume of car
Mass of the car [tex]= 0.54 * 38.2[/tex] [tex]= 20.628[/tex] grams
Acceleration of the car is [tex]10[/tex] m/s^2
Force is equal to product of mass and acceleration
F = [tex]20.628 * 10 = 206.28[/tex] g .m/s^2
Impulse = F * t
Impulse = [tex]206.28 * 10 = 2062.8[/tex] g.m/s
Why is the answer (A)?
In details please
Explanation:
resistance of wire can be determined by this equation
R = Rho . L / A
L = the length of wire
A = the Area, A = πr²
Rho = density of resictance
we can do some rational
R1/R2 = ( Rho L1/A1) / (Rho L2/A2)
L2 is the condition when the length is doubled and
L2 = 2 x L
A2 is the condition when the diameter is doubled
A2 = 4A1
R/R2 = (L1/A1)/(L2/A2)
R/R2 = (L/A) / (2L/4A)
R/R2 = 1 / ½
R2 = ½ R.
then we use formula of Voltage
V = I R
1st condition
V = 0.3 R
2nd condition ( V is constant)
V = I2 R2
0.3 R = I2 x ½R
i2 = 0.3/ ½
i2 = 0.6 Ampere
What happened to the pod during those seconds when communication was lost?
Answer:
Explanation:
From our investigation of what forces are like in a collision, we learned that when two
objects collide, a force is exerted on each object. The two forces are in opposite
directions but the same strength. This allowed us to infer that an equal strength force
was exerted on the space station and the pod, but in opposite directions.
As a result, the space station and the pod are moving in opposite directions. We need to
learn more about the effects of collisions on each object’s motion so we can report back
to Dr. Gonzales at the space agency.
You will use physical materials to gather data about
forces in a collision. You will also notice how objects
are affected by collisions. Students will use their
data to infer the force direction for objects in a
collision.
Based on the velocity change of each object,
what did you infer about the direction of forces
during a collision?
• We observed that the velocity of each object changed during a collision, so we can infer
that a force had to be exerted on each object. However, the motion of the objects
changed in different ways.
• The object that was moving forward slowed down, so I can infer that the force must have
pushed backward on this object.
• The other object started moving forward, so the force must have pushed forward on that
object. If one force was backward and one force was forward, then the forces pushed
the objects in opposite directions.
In Bohr's model, the position of the electron (with the monochromatic light on)... Group of answer choices is restricted to orbits or certain radii, but the electron may be observed between these orbits when it moves. is restricted to orbits of certain radii around the nucleus. The position may change, but it must be in one of these orbits. is not constrained. The electron may be found anywhere outside of the nucleus.
Answer:
True. it is restricted to the orbits of certain radii around the nucleus.
The position can change, but it must be in one of these orbits
Explanation:
In this exercise some affirmations are given and you must select which ones are correct, for this we review the Bohr atomic model that has the following postulates:
* the orbits are circular
* Only certain orbits are stable, stationary state
* the radiation emitted is the difference in energy between two stable orbits
* the size of the orbit is given by the quantization of the angular momentum
L = n [tex]\hbar[/tex]
When reviewing the different statements, the correct one is:
* it is restricted to the orbits of certain radii around the nucleus.
The position can change, but it must be in one of these orbits
A 1500 kg car traveling at 30 m/s hits a stationary 1200 kg car. If they stick together on collision, what is the final velocity of the two cars?
Answer:
16.67 m/s
Explanation:
Let that velocity be v.
Using conservation of momentum:
Initial momentum = final momentum
momentum of car1 = momentum of cars
mass1 x velocity1 = (m1 + m2)v
1500*30 = (1500 + 1200)v
45000/2700 = v
16.67 m/s = v
What two things can change when an object accelerates?
Answer:
speed and velocity or direction.
Background information:
We know that power is the rate that work is done; what that
really means is that power tells up how much work is done every
second. To calculate power we just divide the amount of work that
was done by the time it took to do it (Power=work/time). Work is
measured in Joules and time is measured in seconds, we end up with Joules/sec when we calculate power. A Joule/sec is a Watt; we’ll use Watts to measure and compare power.
We also know that the work done on an object is the amount of energy it has gained. For this activity, you’ll be raising your body up as you do pushups which means you’ll be giving your body gravitational potential energy (GPE). To calculate the amount of GPE we multiply mass time gravity times the height raised (GPE=mgh).
What to do (record everything in the table):
1. You need to have a decent estimate of your mass in kilograms: On earth, every
kilogram weighs 2.2 pounds. Either measure your weight on a scale or just
estimate it (in pounds) then divide by 2.2 to get your mass in kilograms.
2. Measure or estimate the length of your upper arm from your elbow to your
shoulder in centimeters...this is how high you raise yourself for every pushup.
3. Decide if you’ll do regular pushups (on your toes) or simpler pushups (knees). If
you are doing regular pushups, multiply your mass by 0.68 because you’ll only be lifting about 68% of your mass each time; if you’re doing simpler pushups, multiply your mass by 0.52 because you’ll only be lifting about 52% of your mass each time.
4. Measure the time it takes for you to do 10 pushups.
Answer:
Power is the rate at which work is done. It is the work/time ratio. Mathematically, it is computed using the following equation. The standard metric unit of power is the Watt.
Explanation:
How much resistance is required to limit the current from a 12 V battery to 3.6 mA?
Answer:
3333.3 ohm
Explanation:
V=IR so R =V/I (in Ampere) so convert 3.6 mA to 3.6*10^-3 A
so R =12/3.6*10^-3 =3333.3
Need help ASAP on number 4 pls
The Arrows on both sides that has equal length is wrong and the rest of the boxes are the correct
Why are some areas in Europe seeing a partial solar eclipse while others are observing a total solar eclipse?
plz answer ASAP
Answer:
Objects between the source and observer produce possible shadows known as the umbra and the penumbra.
The umbra is a totally shadowed area, no light travels directly from the source to the observer.
The penumbra is a partially shadowed are where some of the source light travels directly to the observer an some of the source light is blocked from the observer (the object blocking the light is not a point object).
The question apparently refers to the differences seen by the observers.
What is the legal BAC for teens in the state of California?