Answer:
So this is just a ratio/proportion problem
so lets say its in boys:minutes
so in the first scenario
20:8
and we want to find
x:10
So proportion really
20/8=x/10
cross multiply
25
25 boys can sweep it in 10 minutes
how can the motion of an object that is already moving change?
Answer: A force can change the direction in which an object is moving
Explanation: A bigger force of an object will produce a bigger change in motion
The velocity (in m/s) of a free-falling object as a function of the height from which it is dropped is
v = 25 h. So, ignoring the air resistance, at what height should you drop a watermelon if you want
it to hit the ground at 50 m/s?
Answer:
Falling objects form an interesting class of motion problems. For example, we can estimate the depth of a vertical mine shaft by dropping a rock into it and listening for the rock to hit the bottom. By applying the kinematics developed so far to falling objects, we can examine some interesting situations and learn much about gravity in the process.
The most remarkable and unexpected fact about falling objects is that, if air resistance and friction are negligible, then in a given location all objects fall toward the center of Earth with the same constant acceleration, independent of their mass. This experimentally determined fact is unexpected because we are so accustomed to the effects of air resistance and friction that we expect light objects to fall slower than heavy ones.
A hammer and a feather will fall with the same constant acceleration if air resistance is considered negligible. This is a general characteristic of gravity not unique to Earth, as astronaut David R. Scott demonstrated on the Moon in 1971, where the acceleration due to gravity is only 1.67 m/s^2.
In the real world, air resistance can cause a lighter object to fall slower than a heavier object of the same size. A tennis ball will reach the ground after a hard baseball is dropped at the same time. (It might be difficult to observe the difference if the height is not large.) Air resistance opposes the motion of an object through the air, while friction between objects, such as between clothes and a laundry chute or between a stone and a pool into which it is dropped, also opposes motion between them. For the ideal situations of these first few chapters, an object falling without air resistance or friction is defined to be in free-fall.
Hope this helps, have a nice day/night! :D
suppose A=3i-2j and B=-i-4j three vectors in xy plane A+B-C =0 what is the answer Ci
Answer:
Ax + Bx = 3 - 1 = 2
Cx = -2
Ay + By = -2 -4 = -6
Cx + Cy = -2 - 6
Then
Ax + Bx - Cx = 2 - (-2) = 0
Ay + By - Cy = -6 - (-6) = 0
C must have the form:
C = -2i - 6j
A train travelling along a straight track starts from rest at point A and accelerates uniformly to 10 m si in 20 s. It travels at this speed for 60 s, then slows down uniformly to rest in 40 sat point C. It stays at rest at C for 30 s, then reverses direction, accelerating uniformly to 5 ms. in 10 s. It travels at this speed for 30 s, then slows down uniformly to rest in 10 s when it reaches point B.
1. Plot a graph of the motion of the train.
II. Use your graph to calculate:
III. the train's displacement from point A when it reaches point C
IV. the train's displacement from point A when it reaches point 13
V. the train's acceleration each time its speed changes.
Please find attached photographs for your answer.
Hope it helps.
Do comment if you have any query.
What is meant by collisions?
Answer:
come into conflict or opposition.
"in his work, politics and metaphysics collide
Which one of the following is not a vector quantity? a) Displacement b ) density c) force d) vecocity
Answer:
density
Explanation:
density is a scalar quantity having only magnitude and no info about derection
Which statement describes the flow of heat? Question 8 options: Heat moves from a warmer object to a cooler object. Heat moves from a cooler object to a warmer object. Heat moves from a cooler object to a warmer object. Heat moves only between two cold objects.
Answer:
A
Explanation:
difference between 1 hectoliter and one kiloliter
Answer: 100 and 1000
Explanation:
2hrt 20 min +60 sec
Answer:
2hr 21 min
Explanation:
0 days 2 hours 20 minutes 0 seconds
+ 0 days 0 hours 0 minutes 60 seconds
= 0 days 2 hours 21 minutes 0 seconds
what frequency of an electromagnetic wave having a wavelenght of 300,000km?
[tex]\huge \bf༆ Answer ༄[/tex]
As we know the relationship between frequency, wavelength and wave speed , we can infer that : -
[tex] \sf \: f = \dfrac{ v}{λ} [/tex]
Terms in the formula
f = frequency v = wave speed = 3 × 10⁸ m/s[ v of all electromagnetic waves is 3 × 10⁸ m/s]
λ = wavelength = 3 × 10⁵ kmλ = 3 × 10⁵ × 10³ mλ = 3 × 10⁸ mTime to find the frequency : -
[tex] \sf \: f = \dfrac{3 \times 10 {}^{8} }{3 \times 10 {}^{8} } [/tex][tex] \sf \: f = 1 \: sec {}^{ - 1} or \: hertz[/tex][tex]꧁ \: \large \frak{Eternal \: Being } \: ꧂[/tex]
which is not a general characteristic of starburst galaxies?
Starburst galaxies is simply known as the rate at which the galaxy is now converting gas into stars. The statement that is not a general characteristic of starburst galaxies is that The "starburst" is thought to be caused by the presence of a supermassive black hole in the galaxy's center.
The starburst galaxy is also regarded as the free quantity of gas with which stars can be formed.They are known to be rare. A starburst is known to be an astrophysical process. It is the process of star formation happening at a rate that is large when compared to the rate that is often observed.
See full question below
Which is not a general characteristic of starburst galaxies?
The "starburst" is thought to be caused by the presence of a supermassive black hole in the galaxy's center. The observed features that us to classily a galaxy as a 'starburst" galaxy must be only temporaryphenomena in the galaxy' Supernovae occur so frequently that their effects combine to drive a galactic wind that blows material into intergalactic space. The galaxy's rate of star formation is many times higher than the rate of star formation in the Milky WayLearn more from
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under what condition could the weight of an object equal zero
Which will be different on the moon than it is on Earth?
weight
mass
Answer:
Below
Explanation:
On the moon, an objects weight will be different than it is on earth. This is because we cannot change the mass of an object, the mass of an object is the measure of matter an object has. However the weight is depended on the gravitational pull of whatever planet you are on. In this case, weight will be lighter on the moon than it is on earth because the moon's gravitational pull is 1.62 m/s^2 while earths is around 9.8 m/s^2.
Hope that helps!
stacie, who has a mass of 45 kg, starts down a slide that is inclined at an angle of 45 degree with the horizontal. If the coefficient of kinetic friction between stacie's shorts and the slide is 0.25, what is her acceleration
The acceleration of the mass sliding along the horizontal surface is 5.2 m/s².
The given parameters;
mass of the crate, m = 45 kgangle, = 45 degreescoefficient of kinetic friction, = 0.25The acceleration of the mass is calculated by determining the net force on the mass as shown below;
[tex]\Sigma F_{net} = ma\\\\Wsin\theta - F_k = ma\\\\mg sin\theta - \mu_k F_n = ma\\\\mg sin\theta - \mu_k mg\ cos\theta = ma\\\\g sin\theta - \mu_k g\ cos\theta = a\\\\g(sin\theta - \mu_k \ cos\theta ) = a\\\\9.8(sin\ 45 \ - \ 0.25\times cos \ 45) = a\\\\9.8(0.53) = a\\\\5.2 \ m/s^2 = a[/tex]
Thus, the acceleration of the mass sliding along the horizontal surface is 5.2 m/s².
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who agree?? with this
Explanation:
ME!!!!!!!!!!!!!!!!!!
Answer:
I Fully Agree with this becoz it is only the key...
Do u agree?
in an electromagnetic wave, the electric and magnetic fields are oriented such that they are
Answer:
The electric and magnetic fields are oriented such that they are perpendicular to one another and parallel to the direction of wave propagation.
In an electromagnetic wave, the electric field and magnetic field are oriented such that they are perpendicular to each other and perpendicular to the direction of propagation.
What are electromagnetic waves?Electromagnetic radiations are made of electromagnetic waves that are produced when an electric field and magnetic field come in contact with each other. Electromagnetic waves are oscillating electric and magnetic fields.
An electric field is generated by a charged particle and a force is exerted by it on other charged particles. Positive charges are accelerated in the direction of the field and negative charges are accelerated in the opposite direction of the field.
The Magnetic field is generated by a moving charged particle and force is exerted by it on other moving particles. The force is always perpendicular to the direction of their velocity.
The electric field and magnetic fields of EM waves are perpendicular to each other and are also perpendicular to the direction of propagation of waves.
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Four landing sites are proposed for a lander. Data about the sites are listed in the table. A 3 column table with 4 rows. The first column is labeled landing site with entries W, X, Y, Z. The second column is labeled height above surface in meters with entries 32, 16, 35, 12. The last column is labeled acceleration due to gravity in meters per second squared with entries 1. 6, 3. 7, 1. 6, 3. 7. At which landing site would the lander have the greatest amount of gravitational potential energy? W X Y Z.
Answer:
its B just finished
Explanation:
Answer:
The answer above is correct! The correct option is B.
Explanation:
Just took the review on edge :)
Hope this helped - brainliest would be appreciated!
Have a great day everyone :D
Please slove this i need answer fast
Answer:
I am not quite sure....
Explanation:
Explanation:
basically i, say the answer is w
if you exert a force on an object, but the object remains stationary as you apply the force, then how much work have you done on the object?
Answer:
no work done
Explanation:
unless you moved the object
When we apply a force on an object, but the object remains at rest when the force is applied, then we have zero work done on the object because the object does not move.
What is Work done?Work done by a force is defined as the product of the displacement and the component of the force exerted by the object in the direction of displacement. Work done is expressed as:
Work done= Force* Displacement
When an object is at rest, there is no external force on it except gravity acting on it, in which case work will be zero because the force acting on it is perpendicular. Thus displacement is zero and if displacement is zero then work done will be zero.
Suppose that displacement is zero then,
W=f×0
Work done is zero
Thus, the work done is zero.
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A rock on the moon has 0.5kg. It is brought to Earth where the gravitational field is stronger. On Earth, the rock will have:
a) Less mass and same weight
b) The same mass and more weight
c) Less mass and less weight
d) The same mass and same weight
Answer:
Explanation:
It will be B.
The correct answer is the same mass and less weight.
What happens to the weight of an object when it is brought from the moon to the Earth?
The weight decreases. Your weight will be 1/6 of the weight on the moon that you had on Earth. This is because the mass of the moon is less hence the gravitational pull is very low compared to Earth.
What happens to the mass of an object when you take it to the moon?
Therefore, the mass of an object on the Moon remains the same as its mass on Earth. But its weight gets less because the gravity on the moon is less than on the Earth.
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What kind of feature results from the convergence of two oceanic plates?
A.
island arcs
B.
massive continental volcanoes
C
rift valleys
D.
tall mountain ranges
Answer:
A
Explanation:
Convergence is pushing them together so C is out of the question.
B and D are wrong because it is an oceanic plate. B and D are for continental plates.
According to the table, what was the hiker's average speed for
the entire hike?
A: 2.0 km/h B: 5.7 km/h C: 6.7 km/h D: 10 km/h
Answer:
6.7 km/h (C)
Explanation:
According to the table, the hiker's average speed for the entire hike would be 6.7 kilometers/hour.
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 total distance traveled by the hiker = 4 kilometers + 6 kilometers + 4 kilometers west + 6 kilometers north
= 20 kilometers
The total time is taken by the hiker = 45 min + 60 min + 30 min+ 45 min
= 180 min
=3 hours
The average speed of the hiker = 20 kilometers / 3 hours
= 6.7 kilometers / hours
Thus, the hiker's average speed for the entire hike would be 6.7 kilometers/hour.
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If you had a stain on your shoe, what would you do to cover it?
Answer: depends what kind of stain and color shoe.
Explanation:
Answer:
Wash the shoe
Explanation:
If the stain is unwashable, then I'd either get new shoes or paint over them.
a tube of constant circular cross-section, sealed at on end, contains an ideal gas trapped by a cylinder of mercury of length 0.035m. The whole arrangement is in the Earth's atmosphere. The density of mercury is 1.36*10^4, more details provided in the images.
Answer:
P V = N R T ideal gas equation
V = .19 * A volume of enclosed gas
.19 P = N R T / A using volume of enclosed gas
P = Po + Phg pressure on gas = atmospheric (Po) + Phg pressure due to column of mercury
.19 (Po + Phg) = N R T / A which is what was asked
Note Phg = density of Hg * height of Hg * acceleration due to gravity
A tube of constant circular cross-section, sealed at on end, contains an ideal gas trapped by a cylinder of mercury of length 0.035m. There will atmospheric pressure and pressure due to mercury column on trapped gas column having length 0.19m which is given by,
(p₀+pm)×0.190 = nRT÷A.
What is Pressure?Pressure is defined as force per unit area. i.e. P = F/A it gives the force on unit area. its SI unit is Pascal (Pa) which is equal to N/m². is a scalar quantity. its dimensions are [M¹ L⁻¹ T⁻²].
Looking at the figure from top to bottom, we can see the top end of the tube is opened. There is 0.035m of mercury column below which we have a air 0.190m of gas column.
We can feel the physics behind this figure what is happening here, top of the tube is open so there is atmospheric pressure acting on the mercury column and mercury column is above the gas column, it means that both atmospheric pressure and mercury pressure will act on gas column.
i.e. (p₀+pm) = pressure on the air column
this (p₀+pm) is downward pressures, hence gas inside the tube gets compressed due to this pressure because bottom end is closed. it means that back pressure will be created inside the gas in upward direction and both pressures becomes equal at equilibrium.
i.e. (p₀+pm) = back pressure inside the gas column......1)
according to ideal gas equation, PV=nRT
pressure inside the air column is P = nRT÷V
where V is volume of gas that is A×0.190.
P = nRT÷(A×0.190).....( back pressure inside the gas column).
equation 1 becomes
(p₀+pm) = nRT÷(A×0.190).
Hence we get
(p₀+pm) ×0.190= nRT÷(A).
Hence proved.
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You and your friend are pushing a box at the same constant speed. You pushed 20 feet in 10 minutes, your friend was pushing for 5 minutes. What distance must she travel so the two of you can travel at the same speed?
Answer:
60 N.C
Explanation:
The box will move in the direction of the push and pull with a force of 60 N. C.
If you and your friend are pushing a box at the same constant speed. You pushed 20 feet in 10 minutes, your friend was pushing for 5 minutes. , then the distance must she travel so the two of you can travel at the same speed would be 30 feet.
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.
As given in the problem If you and your friend are pushing a box at the same constant speed. You pushed 20 feet in 10 minutes, your friend was pushing for 5 minutes.
The distance traveled by box = 20 + 10
= 30 feets
Thus, the distance must she travel so the two of you can travel at the same speed would be 30 feet.
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how to add ratio numbers can someone give me an exzample
Answer:
When the denominator of both ratios is the same, adding the ratio is simple. You just add the numbers to the left of the colon (this number is called the Ratio Numerator)xplanation:
How much work is done when a force of 33 N pulls a wagon 13 meters?
*Round your answer to the nearest whole number.
Answer:
Work = (force) x (distance)
Work = (33N) x (13m) = 429 N-m = 429 joules
IF the force is in exactly the same direction as the motion of the wagon.
Explanation:
pa mark ng brainliest
Using public transports.
Turn off the lights when not in use
Recycle and Reuse
No to plastic bags
Reduction of forest fires and smoking
Use of fans instead of Air Conditioner
Use filters for chimneys
Avoid usage of crackers
how do I put this in a paragraph.
the following can increase the amount of friction in the surface, except ______.
a. glue
b. paper
c. lubricant
d. foil
Answer:
c. lubricant..........
HELP PLZZZZZZ AHHHHH
Answer: I think it's larger
Explanation: man im just trying to help you