A 26-foot ladder is placed against a wall. If the top of the ladder is sliding down the wall at -2 feet per second (note that the rate is negative because the height is decreasing). At what rate is the bottom of the ladder moving away from the wall when the bottom of the ladder is 10 feet away from the wall?
Answer:
Dx/dt = 4,8 f/s
Explanation:
The ladder placed against a wall, and the ground formed a right triangle
with x and h the legs and L the hypothenuse
Then
L² = x² + h² (1)
L = 26 f
Taking differentials on both sides of the equation we get
0 = 2x Dx/dt + 2h Dh/dt (1)
In this equation
x = 10 distance between the bottom of the ladder and the when we need to find, the rate of the ladder moving away from the wall
Dx/dt is the rate we are looking for
h = ? The height of the ladder when x = 10
As L² = x² + h²
h² = L² - x²
h² = (26)² - (10)²
h² = 676 - 100
h² = 576
h = 24 f
Then equation (1)
0 = 2x Dx/dt + 2h Dh/dt
2xDx/dt = - 2h Dh/dt
10 Dx/dt = - 24 ( -2 ) ( Note the movement of the ladder is downwards)
Dx/dt = 48/10
Dx/dt = 4,8 f/s
An average family of four uses roughly 1200 Liters of water per day (1L. - 1000 cm3). A lake that covers 50 km² with a uniform depth and
supplies water to a local town with a population of 40,000 people would lose depth every year due to water consumption form
the locals, Ignore evaporation, rain, creeks and rivers.
Answer:
#_total = 4.38 10⁹ liter
Explanation:
For this exercise we can use a direct proportion rule (rule of three). If 4 people use 1200 liters how much water 1 person consumes
#_water = 1 person (1200 liter / 4 person)
#water = 300 liters
Now we look for the consumption of this person in a year, if 1 person consumes 300 liters 1 day, how many liters they consume in a year (365 days)
#_water_person_total = 365 days (300 liters / 1 day)
#_water_person_total = 109500 liters
This is the water consumption of 1 person in a year, the total of 40000 people how much they consume
#_total = 40000 person (109500 liter / 1 person)
#_total = 4.38 10⁹ liter
If a falling object is covering 50 metre distance in 5 seconds, how much time it will take to cover 72 metres?
Answer:
7.2 seconds
Explanation:
50=5
72=t, criss-cross, t=72 (5)/50
Bus starts from rest if the acceleration of the bus is 0.5 MS squared what will be the velocity at the end of two minutes and what distance will it cover during that time
Explanation:
Given that,
Initial speed of the bus, u = 0
Acceleration of the bus, a = 0.5 m/s²
Let v is the velocity at the end of 2 minutes. The change in velocity divided by time equals acceleration.
So,
[tex]a=\dfrac{v-u}{t}\\\\v=u+at\\\\v=0+0.5\times 120\\\\v=60\ m/s[/tex]
Let d is the distance cover during that time. So,
[tex]v^2-u^2=2ad\\\\d=\dfrac{v^2-u^2}{2a}\\\\d=\dfrac{(60)^2}{2\times 0.5}\\\\d=3600\ m[/tex]
So, the final speed is 60 m/s and the distance covered during that time is 3600 m.
claculate the pressure exerted by the water on the bottom of a deep dam of 12m from its surface .(density of water =1000kg/m sqare)
Explanation:
We know that,
[tex]hydrostatic \: pressure (p) = \alpha hg [/tex]
Where,
[tex] \alpha = density \: of \: water \: = 1000[/tex]
h = Height at which pressure is to be calculated
[tex]p = 1000 \times 12 \times 9.8 = 117600 \: [/tex]
Please Help
A skydiver jumps out of a hovering helicopter, so there is no forward velocity. Use this information to answer questions. Ignore wind resistance for this exercise.
3. What is the skydiver's velocity after one second? Show your work and include direction.
Answer:
The velocity and direction after 1 second is 8.1 m/s downwards
Explanation:
The equation of motion for an object in free fall can be written as follows;
v = u + g×t
Where;
v = The final velocity of the object
u = The initial velocity of the object = 0 m/s
g = The acceleration due to gravity = 9.81 m/s²
The velocity after one second is given by the velocity equation as follows;
v = 0 + 9.81 m/s² * 1 s = 9.81 m/s
The direction of the is downwards due to the attraction by the Earth's gravitational field which acts towards the Earth's center
Therefore, the velocity and direction after 1 second is 8.1 m/s downwards.
This force governs atomic decay.
Answer:
The weak force governs the decay of a neutron into a proton (a process known as beta decay). The strong force binds quarks together into protons and neutrons (the residual strong force holds protons and neutrons together in the nucleus). Gravity governs the motion of an apple falling from a tree.
Explanation:
Answer:
Weak Nuclear force
How is heat transferred during thermal conduction? Through direct contact of particles Through electromagnetic waves Through motion of hot and cold liquid Through the rising of a warm gas
Answer:
Through direct contact of particlesExplanation:
Heat is transferred in the following ways listed below
1. Conduction(Through direct contact of particles )
2. Convection(Through motion of hot and cold liquid )
3. Radiation(Through electromagnetic waves Through the rising of a warm gas )
1. Conduction: This has to do with the transfer of heat from one medium to another having direct contact with each other, the medium can either be solid or liquids
2. Convection: Has to do with the transfer of heat energy via molecules of the liquids in motion with different or varying temperature gradients
3. Radiation: Mostly occurs in gases, it is the transfer of energy through waves
What are three different types of electromagnetic radiation that you use in your everyday life? Be sure to identify the source of the radiation as well as the type of electromagnetic radiation that is used.
Explanation:
Some Uses of Electromagnetic waves :
(A) Microwaves
Satellite CommunicationFor cooking food, etc(B) X - Rays (produced by slowing fast moving electrons)
Used in diagnosis of bones, etcluggage content search at airport, etc(C) Radio Waves
Radio and television broadcasting Navigational communication, etc1.A particle is moving up an inclined plane. Its velocity changes from 15m/s to 10m/s in two seconds. What is its acceleration? *
[tex] \huge{ \underline{ \boxed{ \bf{ \blue{Solution:}}}}}[/tex]
Provided:-Initial velocity = 15 m/sFinal velocity = 10 m/sTime taken = 2 sTo FinD:-Accleration of the particle....?How to solve?We will solve the above Question by using equations of motion that are:-
v = u + ats = ut + 1/2 at²v² = u² + 2asHere,
v = Final velocity u = Initial velocity a = acceleration t = time taken s = distance travelled Work out:By using first equation of motion,
⇛ v = u + at
⇛ 10 = 15 + a(2)
⇛ -5 = 2a
Flipping it,
⇛ 2a = -5
⇛ a = -2.5 m/s² [ANSWER]
❍ Acclearation is negative because final velocity is less than Initial velocity.
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Does the surface tension of water affect the rate of evaporation? If so, would adding a surfactant speed up evaporation?
Answer:
The evaporation time gradually increased with the increase in surfactant concentration, i.e., from water to the concentration level of 0.005%. Furthermore, the evaporation time is significantly reduced, even lower than that of water containing relatively high concentrations from 0.01% to 0.1%.
The particles of a GAS within a closed container will collide with the container walls, exerting a FORCE. The force per unit of AREA is known as what?
Answer:
Pressure
Explanation:
One of the theories propounded by the Kinetic molecular theory, and which also provides an explanation of the several gas laws, is the statement that the gas molecules in a container, travel in straight lines and are in constant collision with themselves and the walls of the container, thus exerting force. This force is the pressure which is defined as the force per unit area.
There is no loss of energy in the collisions involving the gas molecules and that is why their movement can be described as elastic. The descriptions of the behavior of gas molecules in the Kinetic Molecular Theory, give rise to Charles law, Boyle's Law, Avogadro's Laws, Dalton's Law, and Amonton's Law.
Answer:
The pressure
Explanation:
Molecules of gases are constantly in motion, colliding with the walls of their container. This constant collision impacts force on the walls of the container, which depends on the speed with which the molecules are moving. The speed with which these molecules travel depends on the average kinetic energy of the molecules, which is proportional to the temperature.
This force when exerted per unit area is the pressure the gases exert on the walls of the container.
A 4.00-m long rod is hinged at one end. The rod is initially held in the horizontal position, and then released as the free end is allowed to fall. What is the angular acceleration as it is released
Answer:
The angular acceleration α = 14.7 rad/s²
Explanation:
The torque on the rod τ = Iα where I = moment of inertia of rod = mL²/12 where m =mass of rod and L = length of rod = 4.00 m. α = angular acceleration of rod
Also, τ = Wr where W = weight of rod = mg and r = center of mass of rod = L/2.
So Iα = Wr
Substituting the value of the variables, we have
mL²α/12 = mgL/2
Simplifying by dividing through by mL, we have
mL²α/12mL = mgL/2mL
Lα/12 = g/2
multiplying both sides by 12, we have
Lα/12 × 12 = g/2 × 12
αL = 6g
α = 6g/L
α = 6 × 9.8 m/s² ÷ 4.00 m
α = 58.8 m/s² ÷ 4.00 m
α = 14.7 rad/s²
So, the angular acceleration α = 14.7 rad/s²
Astronauts train for space flight in a centrifuge,which consists of a rotating arm with a cab at the outer end of thearm. The arm, which has a length of 58 feet, is revolved about thecenter of the centrifuge. An astronaut sits in the cab, which is thenrotated 50 times per minute. To the nearest hundred feet, how fardoes the astronaut travel in one minute?
Explanation:
We know that,
[tex]v = rw[/tex]
Where, v = tangential velocity (m/sec)
r = radius = 17.67 m
w = angular velocity = 0.83 revs/ sec
v = 14.66 m/sec
Distance in one minute = 879.6 m
= 2885.82 feet
if a direction is somewhere between North and East it is measured in _____?
Answer:
degrees
Explanation:
If a direction is somewhere between north and east, it is measured in degrees.
This measurement will be possible thanks to the existence of geographical coordinates that are some 'imaginary lines' that help us find our location on the earth's surface. These lines are called latitude and longitude, both of which are measured in degrees.
It is like a sea battle game where you have to combine the rows and columns in order to identify where the targets are located. Geographic coordinates work the same way, you must combine the rows and columns of the planisphere to identify the locations of the planet. So the lines would be the latitudes and the columns the longitudes.
Question 5
Calculate the kinetic energy of a car (m - 800 kg) moving at 15 m/s. Write your answer to the nearest whole number in the blank space
provided. Only write the numerical value of the answer without units. Do not leave any space in between numbers.
Answer: Joules
Answer:
90,000Explanation:
[tex]m =800kg\\v = 15\\\\K.E = \frac{1}{2}mv^2\\ K.E= \frac{1}{2} \times 800\times 15^2\\= 400 \times 225\\= 90000 joules\\= 90 kilojoules[/tex]
A 250 watt electric bulb is lighted for 5 hours daily and four 6 watt bulbs are lighted for 4.5 hours daily. Calculate the energy consumed (in kWh) in the month of February.
Answer:
38.024 KWh
Explanation
250 watts multiplied with 5 hours daily multiplied with 28 days monthly equals 35000 Watt hours. Divided by a 1000 to get the KWh equals 35 KWh.
= 250×5hrs× 28days
= 35000watts
= 35000/1000
= 35KWh
Four 6 watt lightbulbs equals 24 watts 4x6=24
Hence, 24×4.5hrs×30days
= 3024watts
= 3024/1000
= 3.024KWhr
The total amount of energy consumed in the month of February = 35 KWh + 3.024 KWh = 38.024 KWh
Note that I had to use 28days since we are considering the month of February.
A skydiver falls toward the ground at a constant velocity. Which statement best applies Newton’s laws of motion to explain the skydiver’s motion? An upward force balances the downward force of gravity on the skydiver. The skydiver’s inertia is zero, which no longer allows for acceleration. An unbalanced force pulls the skydiver toward the ground. The mass of the skydiver is so great that there is no acceleration.
Answer:
The answer is (a.) An upward force balances the downward force gravity on the skydiver
The skydiver is falling at a constant velocity because the upward force is balancing the downward force of gravity. According to Newton, the opposite force balance each other. This is stated in Newton's second law of motion.
The statement that best applies Newton’s laws of motion to explain the skydiver’s motion is that An upward force balances the downward force of gravity on the skydiver.
Newton's 3rd law often applies to skydiving.
When gravity is not acting upon the skydivers they would continue moving in the direction the vehicle they jumped from was moving.
If no air resistance takes place, then the skydivers would still accelerating at 9.8 m/s until they hit the ground.
The skydiver after leaving the aircraft will accelerates downwards due to the force of gravity
usually as there is no air resistance acting in the upwards direction, and there is a resultant force acting downwards, the skydiver will accelerates towards the ground.
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[tex] \large{ \boxed{ \bf{ \color{red}{Universal \: law \: of \: gravitation}}}}[/tex]
Every object in the universe attracts every other object with a force which is proportional to the product of their masses and inversely proportional to the square of the distance between them. The forces along the line joining the centre of the two objects.
❍ Let us consider two masses m1 and m2 line at a separation distance d. Let the force of attraction between the two objects be F.
According to universal law of gravitation,
[tex] \large{ \longrightarrow{ \rm{F \propto m_1 m_2}}}[/tex]
Also,
[tex] \large{ \longrightarrow{ \rm{ F \propto \dfrac{1}{ {d}^{2} } }}}[/tex]
Combining both, We will get
[tex] \large{ \longrightarrow{ \rm{F \propto \dfrac{ m_1 m_2}{ {d}^{2}}}}} [/tex]
Or, We can write it as,
[tex] \large{ \longrightarrow{ \rm{F \propto \: G \dfrac{ m_1 m_2}{ {d}^{2} }}}}[/tex]
Where, G is the constant of proportionality and it is called 'Universal Gravitational constant'.
☯️ Hence, derived !!
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The pH scale is used to tell if a substance
is an acid or base. Substances with a pH
of 7 are neutral. An acid is anything
below 7 and a base is anything above 7.
Bleach has a pH of about 12. What type of
substance is bleach?
A. base
B. acid
C. neutral
Answer: Bleach is a base
Explanation: If bleach had a pH level of 12, a number above 7, than it is a base. Hope this helps!
When astronauts are on spacewalks outside of the International Space Station, they must use a communication system with radio waves to be able to talk to each other. Explain why focusing on the difference between sound and light waves
Light waves are electromagnetic waves while sound waves are mechanical waves. Light waves are transverse while sound waves are longitudinal. Light waves can travel in vacuum. Sound waves require a material medium to travel, and hence, cannot travel in vacuum.
They make use of radio waves. Radio waves signal are sent their headsets that in turn translates the signal in the form of sound. While communicating with people on Earth – the radio waves are transmitted which in turn are transformed to sound wave by a radio set. Radio waves comes from the light spectrum called Electromagnetic Spectrum and thus they are light waves. Unlike sound, light waves doesn’t need a medium to travel and it is for this reason that the sun ray travels through space to the Earth
We all know who was the first man that landed on moon? But were the first words ever heard in space?
It was the announcement of landing that was said by Neil Armstrong: “Lunar Module has landed on moon”
Answer: Light waves are electromagnetic waves while sound waves are mechanical waves. Light waves are transverse while sound waves are longitudinal. Light waves can travel in vacuum. Sound waves require a material medium to travel, and hence, cannot travel in vacuum.
Explanation:
An ideal gas is enclosed in a piston-cylinder apparatus with the piston being freely movable. Given that LaTeX: \DeltaΔE is positive and LaTeX: \DeltaΔH is negative following a process, ____ the system absorbs heat and expands during the process. the system absorbs heat and contracts during the process. the system loses heat and expands during the process. the system loses heat and contracts during the process. the system loses heat but neither expands nor contracts during the process.
Clear question is;
An ideal gas is enclosed in a piston-cylinder apparatus with the piston being freely movable. Given that ΔE is positive and ΔH is negative following a process,
pick one
A) the system absorbs heat and expands during the process.
B) the system absorbs heat and contracts during the process.
C) the system loses heat and expands during the process.
D) the system loses heat and contracts during the process.
E) the system loses heat but neither expands nor contracts during the process.
Answer:
Option A is correct.
Explanation:
In thermodynamics, when the change in energy which is ΔE of a system is positive, it means that the system is undergoing an endothermic process. An endothermic process is simply one where heat is absorbed from the surroundings
Now, when change in enthalpy which is ΔH is negative, it means that it's an exothermic reaction. Exothermic means it releases heat to the surroundings. This means work is positive because the system does work on the surroundings. Thus it will expand.
So the correct answer is;
heat is absorbed from the surroundings and will expand during the process.
What kind of glass is used for car head lamp
Answer:
borosilicate glass
Explanation:
headlamp glass is a borosilicate glass by gravity feed
A control clinic offers a program that guarantees a weight loss of up to 0.46 kg in one week. Express the weight loss in a ratio of milligrams per second.
Answer:
0.76 mg/s
Explanation:
0.46 kg/week × (1 week / 7 days) × (1 day / 24 hrs) × (1 hr / 3600 s) × (1000 g/kg) × (1000 mg/g) = 0.76 mg/s
lab safety test Safety goggles and an apron must be worn when handling chemicals labeled corrosive because they:________.
Answer: React with the skin
Explanation:
lab safety test Safety goggles and an apron must be worn when handling chemicals labeled corrosive because they React with the skin
How large is theta? Please help!!!!
Answer:
30°
Explanation:
The angle between the normal and the vertical is the same as the angle between the incline and the horizontal. We can show this with geometry.
to what temperature must a given mass of nitrogen at zero degrees be heated so both its volume and pressure will be doubled
Answer:
0 degrees Celsius is 273 degrees Kelvin. As both pressure and volume are proportional to absolute temperature, in order to double both you would need to quadruple the temperature. I.e. 273 X 4 = 1092 Kelvin = 819 Celsius
Explanation:
help me pleaseeeeeeddd
Answer:
Explanation:
a )
According to graph the object moves with constant velocity of 10 m /s during first 8 s and then its velocity changes to - 5 m /s from 8 th second upto 12 th second .
Initial displacement = 8 m
displacement during 8 s = velocity x time
= 8 x 10 = 80 m
total displacement = 88 m
b )
displacement during period from 8 th to 12 th s
= - 5 x 4 = - 20 m
total displacement after 12 s
= 88 - 20 = 68 m
c ) average speed = total distance covered during 12 s / total time
= (80 + 20) / 12
= 8.33 m /s
average velocity = total displacement during 12 s / total time
= 80 - 20 / 12
= 60 / 12
= 5 m /s .
Which statement about the dark nebulae is true? Group of answer choices They can be penetrated only with longer wavelengths such as radio and infrared. They block the vast majority of radio waves from our Galaxy. Hydrogen and helium are the chief absorbing and scattering agents. They can be penetrated only with shorter waves, such as UV and x-ray. Only one is known to exist.
Answer:
They can be penetrated only with longer wavelengths such as radio and infrared.
Explanation:
A dark nebula can be defined as an interstellar cloud that is so dense as a result of high concentration of gas and dust and as such it obscures the visible wavelengths of light from stars behind it, thus appearing completely opaque (dark patch) in front of a bright emission nebula or in regions having plenty stars.
Hence, dark nebulae can be penetrated only with longer wavelengths such as radio and infrared light because they cannot be absorbed by the dust layers or particles coated with frozen carbon monoxide and nitrogen residing in the dark nebulae.
. Mass of a man is 40 kg. find his weight (g=9.8 m/s?)
Answer: 392N
Explanation: W=mg
W= 40x9.8
= 392N
Answer:
[tex]\large \boxed{\sf 392.4 \ N}[/tex]
Explanation:
[tex]\sf Weight \ (N) =mass \ (kg) \times acceleration \ of \ gravity \ (m/s^2)[/tex]
[tex]W=mg[/tex]
[tex]W=40 \times 9.81[/tex]
[tex]W= 392.4[/tex]
