Answer:
the focal length of the mirror is : [tex]f=-2.5\,\,cm[/tex]
Explanation:
Use the formula for the formation of image using a divergent mirror and recalling that the image (s') that this mirror formed is virtual, so it is entered as a negative number in the formula. Use the object position (s) as 10, the image position (s') as -2, and derive the value of the focal length:
[tex]\frac{1}{s} +\frac{1}{s'}=\frac{1}{f}\\\frac{1}{10} +\frac{1}{-2}=\frac{1}{f}\\\frac{1}{10} -\frac{1}{2}=\frac{1}{f}\\\frac{10\,f}{10} -\frac{10\,f}{2}=\frac{10\,f}{f}\\f-5\,f=10\\-4\,f=10\\f=-2.5\,\,cm[/tex]
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A diver performs a dive from a 10 m-platform. She
jumps vertically upwards at 3 m s initially.
Find the time she takes to reach the water surface
Answer:
The time she takes to reach the water from when she jumps off the platform is 1.71 s
Explanation:
According to the equations of motion, we have;
v = u - g·t
v² = u² - 2·g·s
s₁ = u₁·t₁ + 1/2·g₁·t₁²
The given parameters are;
The height of the platform (assumption: above the water) = 10 m
The velocity with which she jumps, u = 3 m/s
The acceleration due to gravity, g = 9.81 m/s²
The height to which she jumps, s, is found as follows;
v² = u² - 2·g·s
At maximum height, v = 0, which gives;
0 = 3² - 2×9.81×s
2×9.81×s = 3² = 9
s = 9/(2×9.81) = 0.4587 m
s = 0.4587 m
The time to maximum height, t, is found as follows;
v = u - g·t
0 = 3 - 9.81×t
9.81×t = 3
t = 3/9.81 = 0.3058 s
The total distance, s₁ from maximum height to the water surface = s + 10 = 0.4587 + 10 = 10.4587 m = 10.46 m
The time to reach the water from maximum height, t₁, is found as follows;
s₁ = u₁·t₁ + 1/2·g₁·t₁²
Where;
s₁ = The total distance from maximum height to the water surface = 10.46 m
u₁ = The initial velocity, this time from the maximum height = 0 m/s
g₁ = The acceleration due to gravity, g (positive this time as the diver is accelerating down) = 9.81 m/s²
t₁ = The time to reach the water from maximum height
Substituting the values gives;
s₁ = u₁·t₁ + 1/2·g₁·t₁²
10.46 = 0·t₁ + 1/2·9.81·t₁²
t₁²= 10.46/(1/2×9.81) = 2.13 s²
t₁ = √2.13 = 1.46 s
Total time = t₁ + t = 1.46 + 0.3058 = 1.7066 ≈ 1.71 s.
Therefore, the time she takes to reach the water from when she jumps off the platform = 1.71 s.
A machine can never be 100% efficient because some work is always lost due to which factor? friction gravity static input force
Explanation:
Hi,
The answer is friction.
There is almost no machine which are not affected by friction. It losts some work due to friction while working.
Hope it helps..
Answer:
friction
Explanation:
the other options dont effect efficiency
Guys, can you please answer these three questions. I'm having trouble doing them.
Answer:
17) a) 30 kg·m/s
b) 30 kg·m/s
c) 0.3 m/s.
18) 2.4 m/s
19) 360,000 N
The different make of car is safer because the force acting on it is 28,800 N, resulting much less impact
Explanation:
17) By conservation of linear momentum principle, we have;
m₁·v₁ + m₂·v₂ = m₁·v₁' + m₂·v₂'
Where;
m₁ = The mass of the astronaut = 100 kg
v₁ = The initial velocity of the astronaut = 0 m/s
m₂ = The mass of the equipment box = 2.5 kg
v₂ = The initial velocity of the equipment box = 0 m/s
v₁' = The final velocity of the astronaut
v₂' = The final velocity of the equipment box = 12 m/s
The final momentum of the equipment box = Mass of the equipment box × Final velocity
a) The final momentum of the equipment box = 2.5 kg × 12 m/s = 30 kg·m/s
b) Given that the box and the astronaut will move in opposite directions, we have;
m₁·0 + m₂·0 = -m₁·v₁' + m₂·v₂'
m₁·v₁' = m₂·v₂'
Therefore, the momentum of the astronaut will be equal to the momentum of the equipment box = 30 kg·m/s
c) The velocity of the astronaut is given by th following relation;
100×0 + 2.5×0 = -100×v₁' + 2.5×12
100×v₁' = 2.5×12
v₁' = 2.5×12/100 = 30/100 = 0.3 m/s
The final velocity of the astronaut = 0.3 m/s.
18) By conservation of linear momentum principle, we have;
m₁·v₁ + m₂·v₂ = m₁·v₁' + m₂·v₂'
Where;
m₁ = The mass of the railway truck= 4000 kg
v₁ = The initial velocity of the railway truck= 8 m/s
m₂ = The mass of the stationary truck = 6000 kg
v₂ = The initial velocity of the stationary truck = 0 m/s
v₁' = The velocity of the two trucks immediately after collision
Therefore, we have;
4000 kg × 6 m/s + 6000 × 0 = (6000 + 4000) × v₁' = 10,000·v₁'
24,000 kg·m/s = 10,000·v₁'
v₁' = 24,000/10,000 = 2.4 m/s
The velocity of the two trucks immediately after collision is = 2.4 m/s
19) The change in kinetic energy of the car due to the collision = 1/2·m·(v₂² - v₁²)
The initial velocity of the car, v₁ = 12 m/s
The final velocity, v₂ = 0 m/s
The mass of the car, m= 600 kg
The time in which the car is brought to rest = 2 seconds
Initial time at point of collision, t₁ = 0 s
Time after collision, t₂ = 0.02 s
By Newton's second law of motion, we have
The force F acting on the car = Rate of change in momentum produced by the force
F = m × dv/dt
Force = m × (v₂ - v₁)/(t₂ - t₁) = 600×(0-12)/(0.02 - 0) = -360,000 kg·m/s²
The force acting on the car is equal and opposite to the force of the car = 360,000 N
b) For the different make of the car, we have;
m × (v₂ - v₁)/(t₂ - t₁) = 600×(0-12)/(0.25 - 0) = -28,800 kg·m/s². = -28,800 N
Therefore, the different make of car is safer because the force acting on it is 28,800 N, resulting much less impact.
within a conventional light bulb, which of the following would not be considered a state of matter
a. the glass shell of the bulb
b. the metal base of the bulb
c. the air inside the bulb
d. the light from the bulb
Answer:
D
Explanation:
because light has no space nor mass
You put a piece of ice into a glass of lemonade at room temperature. Which statements explains the heat flow in this scenario? A. Heat flows in both directions. B. Heat flows from the ice to the lemonade. C. Heat flows from the lemonade to the ice. D. Heat flows from the ice to the lemonade to the glass.
Answer:
C. Heat flows from lemonade to the ice
Explanation:
Transfer of heat from the drink to the ice is what melts the ice and cools the drink.
Lyla walks three times per week for 45 minutes at a speed of 4.0 miles per hour. She wants to increase her time what should she do
Answer:
C. Walk four times per week
Explanation:
If she wants to increase her time then, she has to walk four times per week.
What is speed?The total distance covered by any object per unit of time is known as speed. It depends only on the magnitude of the moving object. The unit of speed is a meter/second. The generally considered unit for speed is a meter per second.
The mathematical expression for speed is given by
speed = total distance /Total time
As given in the problem Lyla walks three times per week for 45 minutes at a speed of 4.0 miles per hour. She must walk four times a week if she wants to extend her time.
Thus, the correct answer is option C.
Learn more about speed from here, refer to the link;
brainly.com/question/7359669
#SPJ2
The question is incomplete, the complete question is,
Lyla walks three times per week for 45 minutes at a speed of 4.0 miles per hour. She wants to increase her time. What should she do?
A. Walk at 4.5 miles per hour.
B. Walk for 50 minutes.
C. Walk four times per week.
D. Walk up and down more hills.
'When we see something that exists in real life, there are many different ways to display imagery and importance using art. What the artist _____________ depends on what he/she wants to communicate.'
Answer:
Emphasizes
Explanation:
The expression of an art is intelligible to those that understand it, as such to make an impression an artist has to emphasize the point they want to communicate
An art is an expression of the personal experiences of the artist or a reaction to events or to reveal the realities as seen by the artist such as global warming and the environment, so as to get the attention of people with the goal to change them, such that a good art changes the most people, hence the need for emphasis.
Answer:
A - emphasizes
What is pin hole camera?
Answer:
Explanation:
Pinhole camera is a simple camera. It does not have a lens. The light passes from a hole and an inverted image is formed on the opposite side of the box.
what happens to the displacement vector when the spring constant has a higher value and the applied force remains constant? It remains the same it increases magnitude it changes direction it decreases magnitude
1. Which example best describes a restoring force?
B) the force applied to restore a spring to its original length
2. A spring is compressed, resulting in its displacement to the right. What happens to the spring when it is released?
C) The spring exerts a restoring force to the left and returns to its equilibrium position.
3. A 2-N force is applied to a spring, and there is displacement of 0.4 m. How much would the spring be displaced if a 5-N force was applied?
D) 1 m
4. Hooke’s law is described mathematically using the formula Fsp=−kx. Which statement is correct about the spring force, Fsp?
D)It is a vector quantity.
5. What happens to the displacement vector when the spring constant has a higher value and the applied force remains constant?
A) It decreases in magnatude.
Exercise combined with a _____________________________________can help control weight.
Answer:
healthy diet
Explanation:
Exercise and a healthy diet are the two things people do to stay healthy
Which two possible explanations does the video give for why white light changes into colored light? Color is an impurity added to white light by the prism. Color is present in the materials on which white light shines. White light contains seven colors, which are separated by the prism. White light reacts with chemicals in the air to produce seven colors.
Answer:
White light contains seven colors, which are separated by the prism.
White light reacts with chemicals in the air to produce seven colors.
Explanation:
It was first observed by Sir Issac Newton, that when white light is passed through a prism, an elongated, coloured patch of light is obtained on a screen placed behind the prism. The seven colours obtained constitute the spectrum of white light.
In nature, white light is separated into its constituent wavelengths when white light interacts with substances in the atmosphere.
Answer:
The correct answer is “color is an impurity added to white light by the prism.”
and
“White light contains seven colors, which are separated by the prism
Explanation:
Calculate the average kinetic energy of molecules of a gas at a temperature of 18 ° C
Answer:
6.0×10⁻²¹ J
Explanation:
KE = 3/2 kT,
where KE is average kinetic energy per molecule,
k is the Boltzmann constant,
and T is absolute temperature.
KE = 3/2 (1.38×10⁻²³ J/K) (18 + 273.15) K
KE = 6.0×10⁻²¹ J
Answer:
The answer is 6.0×10⁻²¹ J , because KE = 3/2 kT, where KE is average kinetic energy per molecule, k is the Boltzmann constant, and T is the absolute temperature.
KE = 3/2 (1.38×10⁻²³ J/K) (18 + 273.15) K
KE = 6.0×10⁻²¹ J
anyone can solve these numerical please.
Explanation:
2. Sum the torques about the fulcrum.
(450 N) (2 m) − (350 N) x = 0
x = 2.57 m
3. Sum the torques about the fulcrum.
(3600 N) (0.20 m) − F (0.90 m) = 0
F = 800 N
Mechanical advantage is the ratio between the load force and effort force.
MA = 3600 N / 800 N
MA = 4.5
Velocity ratio is the mechanical advantage divided by efficiency. Assuming the lever is 100% efficient:
VR = 4.5 / 1
VR = 4.5
4. Mechanical advantage is the ratio between the load force and effort force.
MA = 900 N / 600 N
MA = 1.5
The velocity ratio is the distance moved by the effort divided by the distance moved by the load. For a 3 pulley system, VR = 3.
Efficiency is mechanical advantage divided by velocity ratio.
e = 1.5 / 3
e = 0.50
5. Sum the torques about the fulcrum.
(-300 N) (0.10 m) + F (0.03 m) = 0
F = 1000 N
What is the approximate pressure of a storage cylinder of recovered R-404A that does not contain any non-condensable impurities and is stored in a room where the temperature is 80°F?A. 68 psigB. 72 psigC. 174psigD. 288 psig
Answer:
D. 288 psig
Explanation:
The storage cylinder of recovered R-404A is a mixture of R-125, R-143 and R-134. The refrigeration sector has low temperatures for installation. The pressure of cylinder at 80 F will be 288 psig. The pure refrigerants have inside a container have saturation temperature which is equal to ambient temperature.
Which statement describes one feature of Rutherford's model of the atom?
O The atom is mostly empty space.
O The atom cannot be divided into smaller particles.
O Electron clouds are regions where electrons are likely to be found.
O The electrons are located within the positive material of the nucleus.
Answer:
The atom is mostly empty space.
Explanation:
Ernest Rutherford in the year 1911 developed a model of an atom. In his model the atom was shown that the atom is mostly empty spaces composed of negative electrons which orbits round a positive nucleus just like planets revolving round the sun.
Rutherford came up with this model by performing experiments in 1909 which involves the scattering of alpha particles on a thin gold foil. From this experiments he came up with his model.
Answer:
A!
Explanation:
The atom is mostly empty space.
A train is moving along a horizontal track. A pendulum suspended from the roof makes an angle of 4° with the vertical. If g=10m/s2, what is the acceleration of the train?
Answer:
Train accaleration = 0.70 m/s^2
Explanation:
We have a pendulum (presumably simple in nature) in an accelerating train. As the train accelerates, the pendulum is going move in the opposite direction due to inertia. The force which causes this movement has the same accaleration as that of the train. This is the basis for the problem.
Start by setting up a free body diagram of all the forces in play: The gravitational force on the pendulum (mg), the force caused by the pendulum's inertial resistance to the train(F_i), and the resulting force of tension caused by the other two forces (F_r).
Next, set up your sum of forces equations/relationships. Note that the sum of vertical forces (y-direction) balance out and equal 0. While the horizontal forces add up to the total mass of the pendulum times it's accaleration; which, again, equals the train's accaleration.
After doing this, I would isolate the resulting force in the sum of vertical forces, substitute it into the horizontal force equation, and solve for the acceleration. The problem should reduce to show that the acceleration is proportional to the gravity times the tangent of the angle it makes.
I've attached my work, comment with any questions.
Side note: If you take this end result and solve for the angle, you'll see that no matter how fast the train accelerates, the pendulum will never reach a full 90°!
Two mass m1 and m2 lie on a frictionless surface. Between the two masses is a compressed spring, with spring constant k. The system is held in place. At time t=0 the blocks are released. The blocks move off in opposite directions with velocities v1 and v2. how much was the spring compressed?
Answer:
The spring was compressed the following amount:
[tex]\Delta x=\sqrt{ \frac{m_1\,v_1^2+ m_2\,v_2^2}{k} }[/tex]
Explanation:
Use conservation of energy between initial and final state, considering that the surface id frictionless, and there is no loss in thermal energy due to friction. the total initial energy is the potential energy of the compressed spring (by an amount [tex]\Delta x[/tex]), and the total final energy is the addition of the kinetic energies of both masses:
[tex]E_i=\frac{1}{2} k\,(\Delta x)^2\\\\E_f=\frac{1}{2} m_1\,v_1^2+\frac{1}{2} m_2\,v_2^2[/tex]
[tex]E_i=E_f\\[/tex]
[tex]\frac{1}{2} k\,(\Delta x)^2=\frac{1}{2} m_1\,v_1^2+\frac{1}{2} m_2\,v_2^2\\k\,(\Delta x)^2=m_1\,v_1^2+ m_2\,v_2^2\\(\Delta x)^2=\frac{m_1\,v_1^2+ m_2\,v_2^2}{k} \\\Delta x=\sqrt{ \frac{m_1\,v_1^2+ m_2\,v_2^2}{k} }[/tex]
What is the approximate pressure of a storage cylinder of recovered r-410a that does not contain any non-condensable impurities and is stored in a room where the temperature is 80°f?
Answer:
173psig
Explanation:
The storage cylinder of recovered R-410A is mixture of difluoromethane and pentafluoroethane which is used as a refrigerant in air conditioning application. The refrigeration sector has low temperatures for installation. The pressure of cylinder at 80 F will be 173 psig. The pure refrigerants have inside a container have saturation temperature which is equal to ambient temperature.
A containment canister of recovered r-410a has an estimated pressure of 173psig.
The retrieved R-410A preservation container is a blend of difluoromethane and pentafluoroethane, that is used as a compressor in air conditioning systems.
Assembly conditions in the freezer industry are extremely low. At 80 degrees Fahrenheit, the cylinder pressure will be 173 pounds per square inch.
The specific heat capacity of pure refrigeration systems within a cylinder is the same as the room temperature.
Learn more:
https://brainly.com/question/5793747?referrer=searchResults
Se suelta un cuerpo desde la azotea de un edificio de 180m de alto. Luego de 3s se lanza verticalmente hacia abajo otro cuerpo. Si ambos llegan simultáneamente al piso, calcular la rapidez con la que fue lanzado el segundo cuerpo (g=10m/s2).
Answer:CcCcccccc
Explanation:
Rfsgqh
A student uses a spring scale attached to a textbook to compare the static and kinetic friction between the textbook and the top of a lab table. If the scale measures 1,580 g while the student is pulling the sliding book along the table, which reading on the scale could have been possible at the moment the student overcame the static friction?
Answer:1860g
Explanation:The force would have to be greater than 1580g, which is when the student is pulling the sliding book with the spring scale
an object is +2 m from the reference point. the object starts from rest it travels for 3 seconds and has a final position of -16 m. what is the acceleration of the object?
Answer:
Solution
Given:
initial velocity (u)=0m/s (because an object
starts from the rest)
time (t)=3sec
diatance travelled(s)=14m(16-2=14)
acceleration (a)=?
Now,
According to the formula
s=ut+1/2at^2
or,14 =0×3+1/2×a×3^2
or, 14=0+a/2×9
or, 14=9a/2
or, 9a=28
or, a=28/9
or, a=3.1 m/s^2
Therefore, the acceleration of the object is 3.1m/s^2 ans.
Please answer, it's really urgent A boy performs an experiment to measure the speed of sound. He stands 100 meters away form a large wall and claps his hands to make an echo. He claps again as soon as he was the echo, He does this ten times, each time clapping an soon as he hears the echo. The time between the first clap and the tenth echo a recorded. Why it better to time ten echoes together rather than just one echo?
Answer:
Explanation:
The speed of sound is very high . It is about 340 m /s . In one echo , it takes approximately
2 x 100 / 340
= .6 sec
In 10 simultaneous echo , it will take 6 s . It is difficult to measure .6 sec but to measure 6 s is easy and it can be made with greater precision , so we can calculate velocity of sound with great precision .
This is the reason why , instead of one echo , 10 echos are made and duration of 10 echo is measured , rather than making one echo and measuring time of one echo .
Based on its location on the periodic table, which element would be most likely to form a negative ion? A. Bromine (Br) B. Strontium (Sr) C. Potassium (K) D. Magnesium (Mg)
your answer is...
C. potassium
Select the correct answer. Rita is a registered dietician. What does her work entail? A. prescribing medication for clients B. cooking healthy meals for students C. demonstrating how to use gym equipment D. making recommendations for healthy eating habits
Answer:
D
Explanation:
The answer is D because:
A) Only doctors are allowed to prescribe medications.
B) Rita is not a chef/cook.
C) Rita is not a personal trainer
D) The job of a dietican is to provide reccomendations to their clients in order for them to implement a healthy lifestyle via consuming what is best for them.
Hope this helps :)
Answer:
D.) Making recommendations for healthy eating habits
Explanation: PLATO :)))
The ways to measure the mass and volume of irregular object
Answer:
When we have irregular objects, it may become very hard to calculate the volume of the object, as we actually can not use any simple equation to find it.
The mass is less tricky, just find a scale and wheight it, now we know the mass of the irregular object.
One way to measure the volume of the object is using water... how we do it?
Get some recipient with water, measure the height of the water.
Introduce your object into the water and totally submerge it, now the level of the water will rise. This is because as you introduce the object under the water, you are displacing up a given volume of water that has the same volume as the irregular object.
Now that you know the height of the water before and after you put your object, you can easily calculate the volume of water displaced, and that will be the volume of the object (the tricky part may be totally submerging the object if, for example, is wood and it floats, here you can use a thin wire to push it down but it will affect a little bit the measures.)
answer answer answer it it it
Answer:
Parachutes
Explanation:
Your parachute allows you to descend more slowly because it lowers terminal velocity by increasing your air resistance. Most parachutes are designed to create a large amount of drag and allow you to land at a safe, low speed.
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Which has more mass, a 10 N object on the moon, or a 10 N object on the Earth?
Answer:
10N object on the earth
Gravity on moon is one sixth of earth
So a mass weighing 10N weighs 60N on earth .
So a 10N object on moon has more mass
A central air-conditioner uses 3500W of electricity. If electricity costs $0.087/kW*h. calculate how much it would cost to operate the air-conditioner 24 hours a day for 4 months (120 days).
Answer:
$876.96
Explanation:
The energy used is:
3500 W × (24 hr/day) × (120 day) × (1 kW / 1000 W) = 10,080 kWh.
So the cost is:
10,080 kWh × ($0.087 / kWh) = $876.96
White light is spread out into its spectral components by a diffraction grating. If the grating has 1,970 grooves per centimeter, at what angle (in degrees) does red light of wavelength 640 nm appear in first order? (Assume that the light is incident normally on the gratings.)
Answer;
7.238°
Explanation
From question we know that the grating has 1,970 grooves per centimeter, we can convert to from (cm) to (nm) for unit consistency
The slit separation is expressed below
d=1cm/1970
d=0.0005076
=5076nm
Then the angle (in degrees) that the red light of wavelength 640 nm appear in first order can be calculated using expression below
Sin(x)= mλ/d
Where λ= wavelength=640 nm
d=slit separation
Sin(x)= mλ/d
Sin(x)=(1×640)/5076
=0.126
sin-1(0.126)
X= 7.238°
Therefore,the angle (in degrees) that the red light of wavelength 640 nm appear in first order is 7.238°
An object accelerates to a velocity of 230 m/s over a time of 2.5 s. The acceleration it experienced was 42 m/s2. What was its initial velocity?
Answer:
230 = x + 105
x= 125
Explanation:
v = v0 + at
