Answer:
1. Cool air is more dense than warm air so it sinks to take the place of the warm rising/buoyant air.
Explanation:
This is why heating a room with cold outside walls or glass windows (if budget can afford), we use warm radiant heaters at the floor level to break up the convection current/cold draft.
As opposed to just diffusing air at the ceiling level, which is good in summer as cool air falls (air conditioning is in range of 55 to 65 degf out of the diffuser), mixing with warmer room air.
Ifa cup of coffee is at 90°C and a person with a body temperature of 36°C touches it, how will heat flow between
them?
O from the hand to the cup
O from the cup to the hand
O from the cup to the surrounding air
O from the hand to surrounding air
the valency of oxygen is 2
Answer:
Yes the valency of oxygen is 2
Atoms have no electric charge because they
A. Have an equal number of charged and non charged particles.
B. Have neutrons in their nuclei.
C. Have an equal number of electrons and protons
D. Have an equal number of neutrons and protons
Atoms have no electric charge because they have an equal number of electrons and protons.
Explanation:
Atom is the smallest unit of matter.It is comprised of three subatomic particles: protons, electrons, and neutrons.Electrons are found outside the nucleus of an atom and are negatively charged.Protons are found inside the nucleus of an atom and are positively charged.Neutrons are found inside the nucleus of an atom and have no charge.They are electrically neutral because they have an equal number of protons and electrons.So from this, we can conclude that atoms have no electric charge because they have an equal number of electrons and protons. Option C is correct.
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2. A lever has efficiency 60% and mechanical advantage 4, then
(i) Calculate effort required to lift 1000 N load. [250 N] (ii
(ii) Calculate velocity ratio of the lever. [VR = 6.66]
(iii) Find out output work to turn load up to 20 m. [20,000 Nm]
1:0
Answer:
(i) Effort = 250 N
(ii) Velocity ratio = 6.667
(iii) work output = 20 000 Nm
Explanation:
Given: efficiency = 60%, mechanical advantage = 4.
(i) Mechanical advantage = [tex]\frac{Load}{effort}[/tex]
Load = 1000 N
⇒ Effort = [tex]\frac{Load}{Mechanical advantage}[/tex]
= [tex]\frac{1000}{4}[/tex]
= 250 N
Effort = 250 N
(ii) Efficiency = [tex]\frac{Mechanical advantage}{velocity ratio}[/tex] x 100%
Velocity ratio = [tex]\frac{Mechanical advantage}{Efficiency}[/tex] x 100%
= [tex]\frac{4}{60}[/tex] x 100
= 6.667
Velocity ratio = 6.667
(iii) Work output = Load x distance moved by load
= 1000 x 20
= 20 000
Work output = 20 000 Nm
give the relation of resistance of wire with the length and thickness.
Answer:
The answer to this question is given below in the explanation section.
Explanation:
Give the relation of resistance of wire with the length and thickness:
Resistance:
There is a resistance to the flow of an electric current through most conductors.
The length of wire increases
The thickness of wire decreases
The resistance of a long wire is greater then the resistance of a short wire because electrons collide with more ions as they pass through.
The relationship between resistance and wire length is proportional. The resistance of thin wire is greater then the resistance of a thick wire because a thin wire has fewer electrons to carry the current.The relationship between resistance and the area of the cross section of wire is inversely proportional.
in which unit is atmospheric pressure measured?
Answer:
Originally Answered: What is the unit of measurement of pressure in the atmosphere? The SI derived unit of pressure is the pascal , abbreviated Pa. This is a pressure exerted by a force of 1 newton acting over an area of 1m².
Explanation:
Hope this helps you a lot my boo!
How long will it take an object to move 50 meters if the object is traveling with an average speed of 2 meter per second? (Answer to the nearest 100th decimal with units)
Answer:
26
Explanation:
A car drives 16 miles south and then 12 miles west. What is the magnitude of the car's displacement?
04 miles
16 miles
20 miles
28 miles
Answer:
The answer is 20 miles
Explanation:
You would use a^2+b^2=c^2 to get the displacement.
So 16^2+12^2=c^2
400=c^2
c=20
do all objects have inertia
a) true
b) false
Answer:
The answer is A. Which is true
You get a job delivering water. You calculate how much work is done picking up each 20 L bottle of
water and raising it vertically 1 m. For every 100 bottles you deliver, you will use Select.... (g =
9.8 m/s2)
-196J
-2,000 J
-19,600 J
-196,000J
Answer:
The work done by picking up 100 20-L bottles and raising it vertically 1 meter is 19614 joules.
Explanation:
By the Work-Energy Theorem, the work needed to raise vertically 100 bottles of water is equal to the gravitational potential energy, units for work and energy are in joules:
[tex]\Delta W = \Delta U_{g}[/tex] (1)
Where:
[tex]\Delta W[/tex] - Work.
[tex]\Delta U_{g}[/tex] - Gravitational potential energy.
The work is equal to the following formula:
[tex]\Delta W = n\cdot \rho \cdot V \cdot g \cdot \Delta h[/tex] (2)
Where:
[tex]n[/tex] - Number of bottles, dimensionless.
[tex]\rho[/tex] - Density of water, measured in kilograms per cubic meter.
[tex]V[/tex] - Volume, measured in cubic meters.
[tex]g[/tex] - Gravitational acceleration, measured in meters per square second.
[tex]\Delta h[/tex] - Vertical displacement, measured in meters.
If we know that [tex]n = 100[/tex], [tex]\rho = 1000\,\frac{kg}{m^{3}}[/tex], [tex]V = 0.02\,m^{3}[/tex], [tex]g = 9.807\,\frac{m}{s^{2}}[/tex] and [tex]\Delta h = 1\,m[/tex], then the work done is:
[tex]\Delta W = (100)\cdot \left(1000\,\frac{kg}{m^{3}} \right)\cdot (0.02\,m^{3})\cdot \left(9.807\,\frac{m}{s^{2}} \right)\cdot (1\,m)[/tex]
[tex]\Delta W = 19614\,J[/tex]
The work done by picking up 100 20-L bottles and raising it vertically 1 meter is 19614 joules.
WHAT IS THE NET FORCE (CENTRIPETAL FORCE) FOR A 1500 KG
CAR DRIVING 5 M/S AROUND A CURVE, 10 M IN RADIUS?
according to Newton's first law of motion an object at rest will remain at rest and an object in motion will continue to move at a constant velocity because of net force are
A balanced
B unbalanced
C acting in Paris
D the same
Answer:
i think its b
Explanation:
its been awhile since I've worked on Newton's first law
When you're super tired and you lose energy, what energy are you actually losing?
I said Physics class, but it's really for Science class.
Answer:
it is chemical energy
Explanation:
that is the energy used by our body, so it is the one that we will loose. and the energy that we gain is also chemical energy
A weight lifter holds a 800 newton barbell over his head at a height of 6 meters. How much work does the weight lifter do on the barbell?
A. 4800 J
B. 0 J
C. 4800 W
D. 0 W
Answer:
B. o J
hope it helps......
Answer:
A. 4800J
Explanation:
use the formula of work u also can get answer
Please answer faast!!!
Answer:
Any medium or material of high refractive density e.g Water which refracts the light rays 1&2 away from their normal
Define pressure in short
Answer:
hope it helps......
Explanation:
Pressure, in the physical sciences, the perpendicular force per unit area, or the stress at a point within a confined fluid.
How much power does a machine have that does 15204 J of work in 40 seconds?
Explanation:
since P=W/t
P=15204/40
P=380.1 Watt
Why is thermal energy from the Sun transferred to Earth through electromagnetic waves instead of any other type of thermal energy transfer?
Electromagnetic waves can carry energy through matter.
Electromagnetic waves can travel through empty space.
Electromagnetic waves can move through gases faster than other types of energy transfer.
Electromagnetic waves can move more energy than other types of energy transfer.
Answer:
Electromagnetic waves can travel through empty space.
Explanation:
Electromagnetic waves are defined as the waves that are created due to the vibrations between a magnetic field and an electric field.
Earth atmosphere is made up of several gases and spaces between them. Thermal energy from the sun require to pass through space by electromagnetic radiation. Electromagnetic waves can travel through empty space and that is why other type of waves are unable to transfer thermal energy.
Hence, the correct answer is "Electromagnetic waves can travel through empty space".
Answer:
Electromagnetic waves can travel through empty space.B.Explanation:
A box slides down a ramp inclined at 24◦ to the horizontal with an acceleration of 1.7 m/s 2 . The acceleration of gravity is 9.8 m/s 2 . Determine the coefficient of kinetic friction between the box and the ramp.
Answer:
0.445Explanation:
In friction, the coefficient of friction formula is expressed as;
[tex]\mu = \frac{F_f}{R}[/tex]
Ff is the frictional force = Wsinθ
R is the reaction = Wcosθ
Substitute inti the equation;
[tex]\mu = \frac{Wsin \theta}{W cos\theta} \\\mu = \frac{sin \theta}{cos\theta} \\\mu = tan \theta[/tex]
Given
θ = 24°
[tex]\mu = tan 24^0\\\mu = 0.445\\[/tex]
Hence the coefficient of kinetic friction between the box and the ramp is 0.445
Please help!
Tell me types of minor sports except football,
basketball,volleyball,
handball,rugby and waterpolo
ice hokey, indoor soccer
What are the properties of a concave mirror
Answer:
Concave mirrors produce real and virtual images.
Explanation:
(Concave mirrors can produce both real and virtual images)
They can be upright (if virtual) or inverted (if real)
They can be behind the mirror (if virtual) or in front of the mirror (if real)
T hey can also be enlarged, reduced, or the same size as object.
Answer:
Some properties of the given mirror are summarized in the below portion.
Explanation:
Unless the material is dropped between some of the focus as well as the mirror:Throughout that particular instance, the ground image component is immersive but instead larger than those of the attribute and it has a similar orientation as the attribute.
Unless the object is located between some of the center point of that same mirror as well as the focus area:Throughout this particular instance, the mirror version is genuine and larger than that of the attribute. In additament, the image formation was therefore reversed.
Discribe the law of reflection
Answer:
the angle of reflection equals the angle of incidence—θr = θi. The angles are measured relative to the perpendicular to the surface at the point where the ray strikes the surface.
Explanation:
A microscope uses a mirror to reflect light to the specimen under the microscope. ... An astronomical reflecting telescope uses a large parabolic mirror to gather dim light from distant stars. A plane mirror is used to reflect the image to the eyepiece.
Tsunami waves are caused by earthquakes in the ocean floor. As the waves approach the shore, they usually grow in height. When this occurs, which aspect of the wave is changing?
A. amplitude
B. direction
C. frequency
D. speed
E. wavelength
Answer:
LETTER A. AMPLITUDE
:)
Answer:
A
Explanation:
HELP PLS i need this
Answer:
here you have to find the range
Explanation:
[tex]range=\frac{u^{2}sin2\theta }{g}[/tex]
[tex]\frac{4.22^{2} * sin2(63) }{10}[/tex]
1.4431m
A student who weighs 500 N on Earth travels to a planet whose mass and radius are twice that of Earth. His weight on that planet is about
A. 1000 N
B. 500 / V2 N
C.500 N
D. 250 N
Answer:
B
Explanation:
Weight of the student on that planet is about 250 N. option (D) is correct.
What is Newton’s universal law of gravitation?Newton's universal law of gravitation states that the force of attraction between any two bodies is inversely proportional to the square of the distance between them and directly proportional to the product of their masses.
Let the mass of the student be m.
Mass of the Earth = M.
Radius of the Earth = R,
So, gravitational force applied on the student on Earth surface :
GMm/R² = 500 N.
Again,
mass of the planet = 2M
Radius of the planet = 2R.
So, gravitational force applied on the student on the surface of the planet = G(2M)m/(2R)²
= 1/2 {GMm/R²
= 1/2 × 500 N
= 250 N.
Hence, His weight on that planet is about 250 N. option (D) is correct.
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Which of the following will change the strength of a magnetic field?
1.increase speed
2.change the amount of electric current
3.remove atoms
4.it is always the same
2. change the amount of electric current
find the ratio of the lengths of the two mathematical pendulums, if the ratio of periods is 1.5
Answer:
The ratio of lengths of the two mathematical pendulums is 9:4.
Explanation:
It is given that,
The ratio of periods of two pendulums is 1.5
Let the lengths be L₁ and L₂.
The time period of a simple pendulum is given by :
[tex]T=2\pi \sqrt{\dfrac{l}{g}}[/tex]
or
[tex]T^2=4\pi^2\dfrac{l}{g}\\\\l=\dfrac{T^2g}{4\pi^2}[/tex]
Where
l is length of the pendulum
[tex]l\propto T^2[/tex]
or
[tex]\dfrac{l_1}{l_2}=(\dfrac{T_1}{T_2})^2[/tex] ....(1)
ATQ,
[tex]\dfrac{T_1}{T_2}=1.5[/tex]
Put in equation (1)
[tex]\dfrac{l_1}{l_2}=(1.5)^2\\\\=\dfrac{9}{4}[/tex]
So, the ratio of lengths of the two mathematical pendulums is 9:4.
The moon is significantly smaller than the sun. Why is the moon able to fully block the sun from our view on
Earth?
Answer:
The moon is 400x smaller but it's also 400x closer so it looks the same size even though it's not
Explanation:
To solve this we must be knowing each and every concept related to moon. Therefore, the moon is able to fully block the sun from our view on earth as it is 400 times.
What is moon?Any celestial object that revolves around a planet, such as the eight main planets, dwarf planets, or minor planets, is referred to as a moon. In order to distinguish the moon from other celestial bodies that circle other bodies, the term "natural satellite" may also be used to describe the moon.
The Galilean moons orbiting Jupiter, called after astronomer as well as discoverer Galileo Galilei, were the first moons found outside of the moon of Earth. The moon is significantly smaller than the sun. The moon is able to fully block the sun from our view on earth as the moon appears the same size despite the fact that it's 400 times smaller because it is 400 times closer and hence smaller.
Therefore, the moon is able to fully block the sun from our view on earth as it is 400 times.
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I need help with questions #2 and #3
Answer:
Im sorry i can't read it is to small
could anyone solve this...its kinda urgent.
Answer:
1) A = lost volts, B = lower, C = a small pressure, D, = Newtons kg, E = Modulation.
2) A = True(?), B = true, C = True, D = True, E = not sure sorry.
Explanation: