Answer:
Option B
Explanation:
Forces acting on the skier-
F1 [tex]= -mg sin(30)[/tex] down the slope
F2 [tex]= -mg cos(30)[/tex]
F3 = friction force [tex]= 0.74 mg cos(30)[/tex]
Net force, down the slope
[tex]= -mg sin(30)+ 0.74 mg cos(30)\\= mg(.74 cos(30)-sin(30))\\= 0.14mg\\= 1.38m[/tex]
Acceleration [tex]= F/m= 1.38[/tex] m/s2
Acceleration remains constant, initial speed is 20 m/s
Speed at time t is [tex]1.38t- 20[/tex] m/s
Distance down the slope at time t is [tex]0.69t^2- 20t[/tex]
When the skier stops, her speed is 0. Thus,
, [tex]1.38t- 20= 0\\t= 20/1.38\\= 14.5[/tex] seconds
Distance travelled in 14.5 seconds [tex]= (0.69)(14.52- 20(14.5)= -145 m[/tex](negative because it is down the slope).
Option B is correct
what is magnetic flux thru a closed surface
Answer: Zero
Explanation:
Gauss's law states that the total magnetic flux through a closed surface is equal to zero. Because the magnetic field lines are in continuous loops, so all closed surfaces have magnetic field lines coming out, hence the net magnetic flux is zero.
18-A tire rotates at a constant 1.7 radians angle every 0.15 s. A) What is the tire's angular 2 points
velocity? B) If the tire has a diameter of tire is 70 cm, what is the linear speed of the car?*
Explanation:
A) use the formula:
[tex]angular \: velocity = angular \: dispacement \div time[/tex]
B) use the formula:
[tex]linear \: velocity = radius \times angular \: velocity[/tex]
with angular velocity u calculated in A)
One way to conserve energy is to replace incandescent light bulbs with compact fluorescent bulbs. The fluorescent bulb typically uses 25% of the energy of an incandescent bulb of comparable brightness typically lasts about 12 times longer. a)How much would you save by replacing a 100-watt incandescent bulb with a compact fluorescent bulb over the 12,000 hour lifetime of the bulb if the electricity cost 0.08$ per kwh (kilowatt hour)
Answer:
cos to = $ 24
Explanation:
When replacing the bulb only 25% of the energy is used, therefore
W = 0.25 100
W = 25 W
Let's look for the energy in the life of the bulb
E = 25 10⁻³ 12000
E = 300 Kwh
now we can calculate the cost using a direct proportion rule.
Cost = 0.08 300
cos to = $ 24
Biologists use optical tweezers to manipulate micron-sized objects using a beam of light. In this technique, a laser beam is focused to a very small-diameter spot. Because small particles are attracted to regions of high light intensity, the focused beam can be used to "grab" onto particles and manipulate them for various experiments. In one experiment, a 10 mW laser beam is focused to a spot that has a diameter of 0.62 μm.
a. What is the intensity of the light in this spot?
b. What is the amplitude of the electric field?
Answer:
The correct answer is:
(a) [tex]3.31\times 10^{10} \ \omega/m^2[/tex]
(b) [tex]5\times 10^6 \ N/C[/tex]
Explanation:
The given values are:
Power of Laser beam,
= 10 mW
on converting it, we get
= [tex]10\times 10^{-3} \ \omega[/tex]
= [tex]10^{-2} \ \omega[/tex]
Spot's diameter,
= 0.62 μm
= [tex]0.62\times 10^{-6} \ m[/tex]
Now,
(a)
The intensity of light will be:
⇒ [tex]I=\frac{P}{\pi r^2}[/tex]
or,
⇒ [tex]=\frac{4P}{\pi d^2}[/tex]
On substituting the values, we get
⇒ [tex]=\frac{4\times 10^{-2}}{\pi(0.62)^2\times 10^{-12}}[/tex]
⇒ [tex]=3.31\times 10^{10} \ \omega/m^2[/tex]
(b)
The amplitude of electric field will be:
⇒ [tex]I=\frac{1}{2}\epsilon_0E_0.C[/tex]
or,
⇒ [tex]E_0=\sqrt{\frac{2I}{CE_0} }[/tex]
On substituting the values, we get
⇒ [tex]=\sqrt{\frac{3.31\times 10^{10}\times 2}{3\times 10^8\times 8.85\times 10^{-12}} }[/tex]
⇒ [tex]=5\times 10^6 \ V/m[/tex]
How does clothing and body language affect a job interview?
Answer:
please give me brainlist and follow
Explanation:
Whilst first impressions can be important, your body language during the interview can make or break your overall performance. With experts saying that between 75-90% of communication is non-verbal, it is important to think about what your body is saying about you during an interview.
(1) Expansion of concrete
A section of concrete which is 50 meters long experiences a temperature change from -10 Celsius to 46 degrees Celsius. What is the expansion of the concrete?
(2) Stainless steel
A rod of stainless steel (Austenitic) of mass 20 kg has 12057984 Joules of heat added to it. It’s initial temperature is 22 degrees Celsius. The original length is 1 meter.
a. What is the expansion of this rod?
b. Does it melt?
c. What is the final color?
(3) Mystery metal
A rod of some metal is measured to be .6 meters at room temperature (23 Celsius). It is then heated to 99 Celsius and then its length is measured to be .600664. Given the table of expansion coefficients below what type of metal is it? (all numbers in chart are multiplied by 10-6)
material expansion coefficient
silver 19
gold 14.2
indium 33
brass 18
bronze 17.5
What is the change in internal energy if 30 J of heat are released from a
system and the system does 50 J of work on its surroundings?
Use AU= Q-W.
Answer:
Option B. –80 J
Explanation:
From the question given above, the following data were obtained:
Heat (Q) released = –30 J (negative sign because the heat is being released to the surrounding)
Work (W) = 50 J
Change in internal energy (ΔU) =?
We can obtain the change in the internal energy as follow:
ΔU = Q – W
ΔU = –30 – 50
ΔU = –80 J
Therefore, the change in the internal energy is –80 J
Thus, option B gives the correct answer to the question.
What is magnetic flux?
Answer:
plz follow me
Explanation:
ougffgegehhehe
The first version of a product, which is built and tested during the third stage of technological design, is called a
Answer:
Prototype
Explanation:
It's correct on Edge
The first version of a product, which is built and tested during the third stage of technological design, is called a prototype
What are the stages of technological design?There are mainly five stages of the technological design
Identifying the issue that needs to be solved is the first step in every problem-solving process.
The second stage is to imagine; during this phase, a designer would generate several concepts and conduct research on potential creations. They must pick a handful of their greatest concepts and then narrow it down to the best.
The third stage plans the imaging stage's selected product. In this process, the product is designed and drawn in order to be made into a model or prototype while taking into account the limitations that must be overcome.
The fourth step entails assessing, testing, and revising the final product. By creating a model or prototype of their product, the designer may decide what they like and what they could modify. This is found through product testing. If changes are necessary, the designer will go through the process again until they are happy with the outcome.
The fifth step is to share your solution. You present your solution to get feedback, exchange ideas with others, and improve your product. After you've gone through the design process a few times, you might decide to reveal your response to a larger audience in later phases. Similar modifications are made to homework by World of Inquiry students before they deliver it during an excursion.
Thus,a prototype is the initial iteration of a product that is constructed and tested during the third stage of technological design.
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A box is moved 10 m across a smooth floor by a force F making a downward angle with the floor, so that there is effectively a 4 N force acting parallel to the floor in the direction of motion and a 3 N force acting perpendicular to the floor. The force F acts for 20 seconds. The impulse delivered to the box by the floor during this process has magnitude
Answer:
Zero
Explanation:
Impulse is defined as the change in momentum.
Impulse is also defined as the product of force and the time duration of application of the force.
In the given problem, since there is no motion in the vertical direction, therefore the velocity of the box along the vertical direction is zero. So, momentum of the box along the vertical is also zero.
Hence the change is momentum is also zero along vertical direction.
Thus the impulse delivered by the box is zero.
State five uses of bases.
Answer:
Sodium hydroxide is used in the manufacture of soap. It is used in petroleum refining; in making medicines, paper, pulp, etc. It is used in making rayon. Calcium hydroxide is also known as slaked lime. It is used to neutralize acid in water supplies; in the manufacture of bleaching powder; as a dressing material for acid burns; as an antidote for food poisoning.Ammonium hydroxide is used to remove ink spots from clothes and to remove grease from window-panes. It is used in the cosmetic industry. Alkalis are used in alkaline batteries. Generally, potassium hydroxide is used in such batteries.Strontium hydroxide(Sr(OH)2) is used in the food industry for the refining of beet sugar.Ajani is trying to experimentally measure Planck's constant h. He does this by shining different wavelengths of monochro- matic (i.e., single-wavelength) EM radiation on a metal plate with unknown work function W, and then measuring the stop- ping voltage required to bring the ejected electrons to a halt. When he uses λ1= 400 nm, he finds that a stopping voltage of V1 = 0.7 V is required. When he uses λ2 = 500 nm, he finds that a stopping voltage of V2= 0.2 V is required. Based on these two data points, what is Ajani's measurement of Planck's constant?
Answer:
h = 1.01 x 10⁻³⁴ J.s
Explanation:
The energy applied by the voltage must be equal to the energy associated with the wavelength of light:
[tex]eV = \frac{hc}{\lambda}\\[/tex]
where,
e = charge on electron = 1.6 x 10⁻¹⁹ C
V = stopping potential
h = Planck's Constant = ?
c = speed of light = 3 x 10⁸ m/s
λ = wavelength of light
For λ = 400 nm = 4 x 10⁻⁷ m, V = 0.7 V:
[tex](1.6\ x\ 10^{-19}\ C)(0.7\ V) = \frac{h(3\ x\ 10^8\ m/s)}{4\ x\ 10^{-7}\ m}\\[/tex]
h = 1.49 x 10⁻³⁴ J.s
For λ = 500 nm = 5 x 10⁻⁷ m, V = 0.2 V:
[tex](1.6\ x\ 10^{-19}\ C)(0.2\ V) = \frac{h(3\ x\ 10^8\ m/s)}{5\ x\ 10^{-7}\ m}\\[/tex]
h = 0.53 x 10⁻³⁴ J.s
Taking average of both values:
[tex]h = \frac{(0.53+1.49)\ x\ 10^{-19}\ J.s}{2}[/tex]
h = 1.01 x 10⁻³⁴ J.s
5. What do depression and asthma have in common?
a. Both are mood disorders
b. Both affect the same organs
c. Both have similar symptoms
d. Both can be treated
Answer:
a. Both are mood disorders
Explanation:
Depression and asthma are common comorbid diseases and mood disorders in patients with asthma are associated with poor asthma outcomes such as decreased lung function, more frequent emergency department visits and reduced quality of life
How do you make camping fun?
Q1. Which statement is correct
a) Distance and Displacement are the same thing
b) Distance is displacement with direction added
c) Displacement is distance with direction added
Q2. Which statement is true
a) The magnitude of distance and direction must always be the same
b) Distance can be less than displacement
c) Displacement is always the shortest distance between two points
d) Distance follows the exact path while displacement is the straight line distance between starting and ending position
Answer:
C
D
Explanation:
Using a force of 12.0 Newtons, a student pulls a 50.0 Newton weight along the tabletop for a distance of 10.0 meters in
4.0 seconds. Compute the power developed by the student.
Remember to include your data, equation, and work when solving this problem
Answer:30watt
Explanation: Force applied by student F = 12 N
Displacement s = 10 m
Time t = 4 s
Work done W = Fs
Power P = W/t = Fs/t
= 12 * 10/4 Watt
= 30 Watt
The power developed by the student is 30 Watt.
To find the value of power the given values are,
Force applied by the student F = 12 Newton,
Distance s = 10 meters,
Weight pulled by the students = 50 Newton,
Time t = 4 seconds.
How work done and power are related to one another?Work done:
The product of displacement of an object and the component of the applied force which is in the direction of the object's displacement is said to be Work done.
It's unit is kg⋅m²⋅s⁻² or Joules.
Work done W = Force ( F ) × Distance ( S )
= 12 × 10
= 120 J.
Power:
Power can be defined as the ratio of work done to time interval.
[tex]P = \frac{W}{\Delta t}[/tex]
It's unit is Watt.
Power , P = 120 / 4
P = 30 Watt.
Thus, the power developed by the student is 30 watt.
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who invented physics?
Answer:
I think Albert Einstein invented physics.
Explanation:
Iam soory if Iam wrong.
1. Which energy is stored in the bonds between atoms?
Answer:
Explanation: Energy, potential energy, is stored in the covalent bonds holding atoms together in the form of molecules. This is often called chemical energy.
How does mass differ from weight? List 2 differences.
weight is vector vary from place to place
Answer:
The difference between mass and weight is that mass is the amount of matter in a material, while weight is a measure of how the force of gravity acts upon that mass.
Explanation:
Mass is the measure of the amount of matter in a body. Mass is denoted using m or M. ... Weight is mass multiplied by the acceleration of gravity (g).
HELP WITH SCIENCE STAAR QUESTIONS
Answer:
EASY PEASY LEMON-SQUEEZY.
Explanation:
B
Mark Brainliest.
why is it important to observe safety rules in food preservation?
pls help
Answer:
Yes it is important.
Explanation:
It is important because we should preserve our food with safety as we would take it in the next day so if we we will not take safety then many germs can enter in that food and if we eat that food we could get sick . If we keep the food uncovered so anything can happen like any insect can fall in the food and we didn't know it it or any germs can enter in the food that is very harmful for our body so so we should keep the food covered and well preserved.
Question
A car is moving on a flat roadway, What can be said about this system
A. The Kecan change there is no conservation of energy
B. It is not an isolated system because the car moves,
c. The law of conservation of energy applies,
O D. There is no PE, so no conservation of energy.
SOMEONE HELP PLEASE I ASKED THIS TWICE LAST NIGHT I MEAN DAM!! You drop a water balloon from a second-story window. Which formula would you use to calculate the velocity of the water balloon just before it hits the ground, assuming it is in free fall?
A. v=g/t B. v=get C. g=vt D. t=vg
Answer:
I think it would be V=g/t
HELP PLZ 50 POINTS SPACE QUESTION
Explain how tilt results in varying sun angles that affect temperature
During the winter, the Northern Hemisphere tilted away from the sun, receiving solar radiation at more of an angle. This results in colder temperatures and more extreme temperature changes.
In a direct current motor, what is the result of the magnetic field acting on the wire
Answer:
Because the magnetic field created by the electric current in the wire is changing directions around the wire, it will repel both poles of the magnet by bending away from the wire.
Explanation:
how do you define teaching?
Answer:
Teaching is the process of attending to people's needs, experiences and feelings, and making specific interventions to help them learn particular things.
Explanation:
Hope it helps✌Answer:
In education, teaching is the concerted sharing of knowledge and experience, which is usually organized within a discipline and, more generally, the provision of stimulus to the psychological and intellectual growth of a person by another person or artifact.
A uniform 40-N board supports two children weighing 500 N and 350 N. If the support is at the center of the board and the 500-N child is 1.5 m from its center, How far is the 350-N child from the center
Determine the upward force exerted on the board?
Answer:
2.14 m
Explanation:
2.14m if it is write thank me hitting the heart ❤️ I took a lot of time to solve
a man hikes 6.6 km north along a straight path with an average velocity of 4.2 km/h to the north. he rest at a bench for 15 min. then, he hikes 3.8 km birth with an average velocity of 5.1 km/h to the north. how long does it take the total hike to last
Answer:
2.6h
Explanation:
I attached the image below of the work hope you can see it. Hope this helps!
Man takes approximately 2.56 hr to hike to last.
What is average velocity ?
Average velocity is given by the total distance covered by the object in total given time.
here, to calculate total time "t" taken by the man to hike at last it will be equals to the sum of the time "t₁" taken to travel 6.6km, time "t₂" he had taken rest and time "t₃" he had taken to travel 3.8 km.
Therefore, total time t is calculated :
[tex]\begin{aligned}t&=t_{1}+t_{2}+t_{3}\\&=\frac{6.6}{4.2}+\frac{15}{60}+\frac{3.8}{5.1}\\&\approx 2.56 \text{\:h}\end{aligned}[/tex]
Thus the man takes approximately 2.56 hr to hike to last.
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Explain how the forces need to change so the aeroplane can land
The explanation with regard when the forced are required to changed is explained below:
In the case when an airplane is flying straight and level at a constant speed, the lift it generated balances its weight, and the thrust it produces balances its drag. But this balance of forces changes because the airplane rises and descends, also it speeds up and slows down, and it turns.Learn more: brainly.com/question/16911495
Which of the following is not a characteristic of electrical potential energy?
Answer:
It is a form of mechanical energy
Explanation: