Answer:
27: 85
28:75%
Explanation:
27:68=80
?=100 hence (68×100)÷80
=85
28:18/24× 100
=75%
A pail in a water well is hoisted by means of a frictionless winch, which consists of a spool and a hand crank. When Jill turns the winch at her fastest water-fetching rate, she can lift the pail the 26.0 m to the top in 12.0 s. Calculate the average power supplied by Jill's muscles during the upward ascent. Assume the pail of water when full has a mass of 6.50 kg. W
Answer:
140.83 W
Explanation:
From the question given above, the following data were obtained:
Height (h) = 26 m
Time (t) = 12 s
Mass (m) = 6.50 Kg
Power (P) =?
Power is simply defined as the rate at which energy is used up. Mathematically, it is expressed as:
Power (P) = Energy (E) / Time (t)
But:
Energy (E) = mass (m) × acceleration due to gravity (g) × height (h)
E = mgh
P = E/t
P = mgh / t
With the above formula i.e
P = mgh / t
We can obtain the power supplied by Jill's muscles as follow:
Height (h) = 26 m
Time (t) = 12 s
Mass (m) = 6.50 Kg
Acceleration due to gravity (g) = 10 m/s²
Power (P) =?
P = mgh / t
P = 6.5 × 10 × 26 / 12
P = 140.83 W
Therefore, the power supplied by Jill's muscles is 140.83 W
Look at the circuit diagram. What does the diagram show?
Answer:
the second one i gues
Explanation:
the stripes tells about the batery input/ the x is the lightbulbs/ and two switches
finger bones do not have joints true or false
Explanation:
Finger bones have joints.
Answer: true , finger bones have joints
Explanation:
A 1.6-kg ball is attached to the end of a 0.40-m string to form a pendulum. This pendulum is released from rest with the string horizontal. At the lowest point of its swing, when it is moving horizontally, the ball collides with a 0.80-kg block initially at rest on a horizontal frictionless surface. The speed of the block just after the collision is 3.0 m/s. What is the speed of the ball just after the collision?a. 1.5 m/sb. 1.3 m/sc. 2.1 m/sd. 1.1 m/se. 1.7 m/s
Answer:
a. 1.5 m/s
Explanation:
We will apply the law of conservation of energy in this situation between the initial position and the lowest point of the swing:
[tex]m_{1}u_{1} + m_{2}u_{2} = m_{1}v_{1} + m_{2}v_{2}\\[/tex]
where,
m₁ = mass of ball = 1.6 kg
m₂= mass of block = 0.8 kg
u₁ = initial speed of ball = 0 m/s
u₂ = initial speed of block = 0 m/s
v₁ = final speed of ball = ?
v₂ = final speed of block = 3 m/s
Therefore,
[tex](1.6\ kg)(0\ m/s)+(0.8\ kg)(0\ m/s)=(1.6\ kg)(v_{1})+(0.8\ kg)(3\ m/s)\\\\v_{1} = \frac{2.4\ N.s}{1.6\ kg}\\[/tex]
v₁ = 1.5 m/s
Therefore, the correct option is:
a. 1.5 m/s
two masses are attached by a light string and looped over two frictionless pulleys. object 1 has mass 200g and accelerates upwards at the rate of 4.90m/s^2. determine the mass of object 2
Answer:
F=ma
F=10(mass of object 2-0.2)
F=ma
=0.2×4.9
=0.98N
10x-2=0.98(assume that mass of second object is X)
10x =0.98+2
10x=2.98
X=0.298kg
the mass of second object=298g
t
for the hypothetical salaries in the following
dataset, what is the average salary per year?
Data set of hypothetical salaries: $46,000 per year,
$20,000 per year, $33,000 per year, $27,000 per year,
$91,000 per year.
Answer: $43400 per year
Explanation:
The Data set of hypothetical salaries is given as:
$46,000 per year,
$20,000 per year,
$33,000 per year,
$27,000 per year,
$91,000 per year.
The average salary per year will be the addition of the salaries per year above which will then be divided by 5. This will be:
= ($46,000 + $20,000 + $33,000 + $27,000 + $91,000) / 5
= $217000/5
= $43400 per year
The average salary per year will be $43400
. What is the height in meters of a 5'4" person?
Answer:
1.62 meters
Explanation:
For an approximate result, divide the feet (height) by 3.3 to get your approximate meters (height).
Two objects A and B (both masses are m) are connected by a spring of elastic constant k and placed on a frictionless surface. At some point, A gains an initial velocity v parallel to the spring, and this system will thus start moving. Knowing that the spring is undeformed in the beginning, determine (a) the highest elastic potential energy that can be stored in the spring and (b) the highest velocity that can be reached by B.
Answer:
a) Em_f = ½ m vₐ², b) v = vₐ /√2
Explanation:
a) For this part we use conservation of energy
starting point .. block A moving, spring unstretched
Em₀ = K = ½ m vₐ²
end point. Stretched spring
Em_f = K_e = ½ k x²
energy is conserved
Em₀ = Em_f
Em_f = ½ m vₐ²
b) Let's analyze the movement a little, block A began to move at a speed va, I stretch the spring an amount Dx, it exerts a force on block b that begins to move and the elongation of the spring decreases.
In all this process there is no friction force, therefore the energy is conserved, therefore the maximum energy stored in the spring must be distributed among the bodies.
Em₀ = K_e = E₀
where E₀ is the initial energy of block a
E₀ = ½ m vₐ²
At the point where we are in equilibrium
Em_f = Kₐ + K_b = ½ m vₐ² +1/2 m [tex]v_{b}^2[/tex]
so that the spring does not stretch or shrink, the two bodies must go at the same speed.
Em_f = m v²
energy is conserved
Em₀ = Em_f
½ m vₐ² = m v²
v = vₐ /√2
therefore both blocks must go at this speed
8. When an object is 28 cm in front of a
concave mirror, the image is 16 cm in front
of the mirror? What is the focal length of
the mirror?
*
FORMULA
[tex] \frac{1}{f} = \frac{1}{p} + \frac{1}{l} [/tex]
p-the distance of the figure(object)from the vertex of the mirror
l-the distance of the figure from the vertex of the mirror
Charging by Contact examples
Answer:
the hair and the comb are both neutral
define prism and itz colo
Answer:
A prism is a piece of glass or plastic in the shape of a triangle.
Explanation:
The colors of the rainbow in order are: red, orange, yellow, green, blue, indigo, and violet.
PLEASE HELP ME WITH THIS ONE QUESTION
A tuning fork of 500 Hz is struck in a room with a speed of sound of 340 m/s. What is the distance between a point of rarefaction and the next compression point, in the resulting sound?
Answer:
0.34 m
Explanation:
From the question,
v = λf................ Equation 1
Where v = speed of sound, f = frequency, λ = Wave length
Make λ the subject of the equation
λ = v/f............... Equation 2
Given: v = 340 m/s, f = 500 Hz.
Substitute these values into equation 2
λ = 340/500
λ = 0.68 m
But, the distance between a point of rarefaction and the next compression point, in the resulting sound is half wave length
Therefore,
λ/2 = 0.68/2
λ/2 = 0.34 m
Hence, the distance between a point of rarefaction and the next compression point, in the resulting sound is 0.34 m
True or false—If a rock is thrown into the air, the increase in the height would increase the rock’s kinetic energy, and then the increase in the velocity as it falls to the ground would increase its potential energy.
If a rock is thrown into the air, the increase in the height would increase the rock’s kinetic energy, and then the increase in the velocity as it falls to the ground would increase its potential energy. _ This is false statement.
What is projectile motion?When a particle is hurled obliquely near the surface of the earth, it travels along a curved path while accelerating continuously in the direction of the planet's center (we assume the particle stays close to the surface of the globe). Such a particle's motion is known as projectile motion, and its route is referred to as a projectile.
In projectile motion total energy is conserved. Hence, when a rock is thrown into the air, the increase in the height would increase the rock’s potential energy, and then the increase in the velocity as it falls to the ground would increase its kinetic energy.
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Why do scientists perform multiple trials of the same experiment?
Answer:
it's a good idea to do multiple trials, that is, do the same experiment lots of times. When we do multiple trials of the same experiment, we can make sure that our results are consistent and not altered by random events. Multiple trials can be done at one time.
Explanation:
the last one which is to increase the likelihood of accurate experiment results
Explanation:
Explain how the plants of a tropical rain forest contribute to the characteristic hot, humid weather associated with the area. Use details to support your answer.
Answer: The atmosphere of trophic rainforest is hot and humid due to high rate of transpiration.
Explanation:
The tropical rainforest is a biome which exhibit rich biodiversity of plants and animals. The average temperatures in this region remain high with warm summer. It remains frost free. The soil is nutrient deficient. Due to hot temperature the rate of transpiration remains high as a result the concentration of the water vapors remain high. This is responsible for increasing the humidity in the atmosphere also this region receives appreciable amount of rainfall annually. The average rainfall range is 200-450 centimeters.
ANSWER DIS ASAP FOR LUCK TMRW :}
List down ten situations that show how friction affects the movement of objects. I NEED THE ANSWER IN ONE MINUTE
Answer:
Walking –We can walk only if we apply frictional force. Friction is what holds your shoe to the ground. The friction present on the ice is very little, this is the reason why it is hard to walk on the slippery surface of the ice.
Writing – A frictional force is created when the tip of the pen comes in contact with the surface of the paper. Rolling friction is what comes into play while writing with a ballpoint pen while sliding friction arises when one writes with a pencil.
Skating – A thin film of water under the blade is necessary to make the skate slide. The heat generated by the skate blade rubbing against the surface of ice causes some of the ice to melt right below the blade where the skater glides over the ice. This water acts as a lubricant reducing friction.
Lighting a matchstick – When the head of the matchstick is rubbed against a rough surface, heat is generated and this heat converts red phosphorous to white phosphorous. White phosphorous is highly inflammable and the match stick ignites. Sometimes, matchsticks fail to ignite due to the presence of water. Water lowers friction.
Driving of the vehicle on a surface- While driving a vehicle, the engine generates a force on the driving wheels. This force initiates the vehicle to move forwards. Friction is the force that opposes the tyre rubber from sliding on the road surface. This friction avoids skidding of vehicles.
Applications of breaks in the vehicle to stop it- Friction braking is the most widely used braking method in vehicles. This process involves the conversion of kinetic energy to thermal energy by applying friction to the moving parts of a vehicle. The friction force resists the motion and in turn, generates heat. This conversion of energy eventually bringing the velocity to zero.
Flight of aeroplanes- Drag is the force that opposes the forward motion of the aeroplane. The friction which resists the motion of an object moving through a fluid or immobile in a moving fluid, as occurs when we fly a kite. The friction of the air is created as it meets and passes over an aeroplane and its components. Drag is generated by air impact force, skin friction and displacement of the air.
Drilling a nail into the wall- Friction is responsible for fixing of nails in a wall. As the nail is driven into the wall, the nearby material to the nail of the wall gets compressed. This exerts a force on the nail. This force is the friction that converts the normal force exerted by the compressed layers of the wall into the resisting shear force. In this manner the friction cause nails and screws to hold on to walls.
The dusting of the carpet by beating it with a stick- When the carpet is beaten with the stick, the dust comes out. The dust is carried off by the wind or falls on the floor. The carpet exhibits a little static friction that holds the dust to the carpet. When the carpet is beaten, it will overcome the friction and the carpet will move away from the dust making the carpet free from dust.
Sliding on a garden slide- We know that friction is a force that is present whenever two objects rub against each other. In case of a slide in the garden such as a slide and a person’s backside rub each other’s surface. Without friction, a slide would accelerate the rider too quickly, resulting in possible injury due to the fall. The friction reduces the velocity of the sliding person and makes him stop.
Hope that helps! :D Sorry if it's too lengthy...
Explanation:
help, it's an emergency !!!!!!!
An elevator motor in a high-rise building can do 3500 kJ of work in 5 min. Find the power developed by the motor. Explain if you can plz
Answer:
P = 11666.6 W
Explanation:
Given that,
Work done by the motor, W = 3500 kJ
Time, t = 5 min = 300 s
We need to find the power developed by the motor. Power developed is given by :
[tex]P=\dfrac{E}{t}\\\\P=\dfrac{3500\times 10^3}{300}\\\\P=11666.7\ W[/tex]
So, the required power is 11666.6 W.
Which is a primary energy source used by power plants to generate electricity?
coal
O wood
o gasoline
batteries
Answer:
Your answer is wood that is what they used
The primary energy source used by power plants to generate electricity is coal.
What are power plants?Power plants are plants which use fuels to generate electricity for use by homes and industries.
Power plants have different energy sources for their fuel.
The primary energy source used by power plants to generate electricity is coal.
Therefore, coal is a primary source of fuel for power plants.
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a)Hari drove for 2 hours at a speed of 60km/h and next3 hours at a speed of 70km/h. Calculatehis average speed for the whole journey.b)A police car drives with a constant speed of 70km/h. How long it will take to cover a distance of 135 km? Express the speed in m/s
Answer:
Remember the relation:
Speed*Time = Distance.
Then first let's find the total distance that Hari drove.
First, he droves 2 hours at 60km/h, then the total distance traveled is:
Distance = 2h*60km/h = 120km
Then he droves 3 hours at 70km/h
The distance here is:
Distance = 3*70km/h = 210km
The total distance traveled is 120km + 210km = 330km
The total time of the travel is 2 hours + 3 hours = 5 hours.
The average speed is calculated as:
Av speed = (total distance)/(total time)
Av speed = (330km)/(5 h) = 66km/h
The average speed is 66km/h.
b) We know that the speed is 70km/h, but we want to write this in m/s.
Then we first know that 1 km = 1000m
then:
1 = (1000m/1km)
Then 70km/h = 70 km/h*(1000m/1km) = (70*1000) m/h = 70,000 m/h
Now we know that 1h = 3600 seconds, then:
1 = (1h/3600s)
So we can write:
70,000 m/h = (70,000 m/h)* (1h/3600s) = 70,000/3600 m/s = 0.019 m/s
and the distance is 135 km
Again, we can rewrite this as:
135km = 135km*(1000m/1km) = 135,000m
Then we want to solve:
(0.019m/s)*time = 135,000 m
We want to solve this for the time, then we get:
time = (135,000m)/(0.019m/s) = 7,105,263.2 seconds = 1.93 hours
Match the following items.
1. Extremely small building blocks of matter.
2. Forming new matter from old matter.
3. Small bits of matter.
atom
molecule
chemical change
This square solenoid has sides length 25 cm, and 100 turns of wire. The resistance is 10 ohms. Find the magnitude of the induced emf in the coil if the magnetic field of 10 T is passing through the face of the loop as pictured. What is the induced current in the wire. Find the emf and current if the solenoid was a circle with radius 25 cm instead of a square.
Explanation:
Area of square = 25^2 = 625 cm^2 or = 0.0625 m^2
number of turns = 100
Solenoid resistance = 10 ohms
now we know , Φ = B.A
where , Φ = magnetic flux, B= magnetic field strength, and A = area.
Φ = 10 × 0.0625 = 0.625 W
induced emf ε = dΦ/dt = d(BA)/dt =0
This is because both B and A are constants.
⇒ Induced current is also zero.
Replacing square by a circle will not change situation as the value of B and A will remain constant with time hence, no emf induced, so no current induced.
Which of these describes static electricity?
a temporary charge
a steady charge
plssssssssssssssss answer not in a meen way but correct answers only plssssssssssssssssssssssssssssssssssssssssssssssss answer correctly i will drop a thx and give you brainlest and rate your answer 5 stars if you are correct
a temporary charge is the right answer
What is double stroking
Answer: The double stroke roll works just like the single stroke roll - it's played in a sequence of alternating strokes (roll). But instead of having one stroke per hand you'll have two, as shown on the sheet music below. You can use full wrist turns to play each stroke of the double stroke at slower speeds.
Explanation: hope this helps!
Explanation:
it is played as a sequence of alternating strokes
How to calculate the voltage of a light bulb
An acceleration constraint says that in some circumstances An acceleration constraint says that in some circumstances the acceleration of an object has to be positive. two objects have to accelerate in the same direction. two objects must have accelerations of equal magnitude. an object is prevented from accelerating.
Answer:
two objects must have accelerations of equal magnitude.
Explanation:
In physics, acceleration can be defined as the rate of change of the velocity of an object with respect to time.
This simply means that, acceleration is given by the subtraction of initial velocity from the final velocity all over time.
Hence, if we subtract the initial velocity from the final velocity and divide that by the time, we can calculate an object’s acceleration.
Mathematically, acceleration is given by the equation;
[tex]Acceleration (a) = \frac{final \; velocity - initial \; velocity}{time}[/tex]
[tex]a = \frac{v - u}{t}[/tex]
Where,
a is acceleration measured in [tex]ms^{-2}[/tex]
v and u is final and initial velocity respectively, measured in [tex]ms^{-1}[/tex]
t is time measured in seconds.
Acceleration constraint refers to a precise relationship between the acceleration of two physical objects.
An acceleration constraint says that in some circumstances two objects must have accelerations of equal magnitude.
A wave of frequency 500hz and wave length 50m is traveling into a medium, dertimine the speed of velocity of the wave. formula V=f×d.
Answer:
25000m/s
Explanation:
V=fd
V=(500)(50)
V=25000m/s
Ans
Sep 19, 2019 — Wave speed is the distance a wave travels in a given amount of time, such as the ... Wave speed is related to both wavelength and wave frequency. ... The equation for wave speed can be used to calculate the speed of a wave when both ... Frequency = SpeedWavelength or Wavelength = SpeedFrequency.
Explanation:
Which of the following technologies would produce the least energy in light
waves?
A. Ultraviolet disinfecting wand
B. Microwave industrial drying equipment
C. Radio-controlled toy airplane
D. Halogen lightbulb
Answer: C. Radio-controlled toy airplane
Explanation:
Just did the quiz
Radio-controlled toy airplane technologies would produce the least energy in light waves. Hence option C is correct.
Energy of the electromagnetic wave is directly proportional to frequency of the light wave. This relation is given by, E =hυ where h is planks constant and υ is frequency of light wave.
Remote of the radio controlled toy airplane produces radio waves to communicate between remote and the plane. Radio wave have high wavelength and low frequency, hence it has least energy as compare to UV light and and microwave light. Ultraviolet disinfecting wand produces ultraviolet light whose frequency is high than the microwave and radio waves.
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1. Which statement best describes the cycle of water through the human body?
A Water is taken into the body through transpiration and released through perspiration.
B Water is taken into the body through ingestion and released through perspiration.
C Water is cycled through the body through the process of transpiration.
D Water is taken into the body through perspiration and released through transpiration.
Answer:
I would say B
Explanation:
the other ones don't seem right
What is an indicator?
A. An organic compound that changes color in acids and bases
B. A strong acid
C. The amount of ions in solution
D. The concentration of acids or bases