Answer:
Explanation:
The formula for centripetal acceleration is
[tex]a_c=\frac{v^2}{r}[/tex] and filling in:
[tex]11.3=\frac{(30.0)^2}{r}[/tex] and solving for r:
[tex]r=\frac{(30.0)^2}{11.3}[/tex] gives us that
r = 79.6 m
In uplifting 750 newton load with the help of 2 meter long lever lever took 250 newton efforts . What will be the efficiency of a machine if the fulcrum is kept 50 cm from the load
Answer:
the efficiency of the machine is 100%
Explanation:
Given;
load, L = 750 N
length of the lever, L = 2 m
effort applied, E = 250 N
Position of the load from the fulcrum, = 50 cm
50cm
0↓--------------------------Δ-------------------------------↓---------200 cm
750 N x cm 250 N
Apply the principle of moment;
750(50) = 250(x)
x = (750 x 50) / (250)
x = 150 cm
the distance of the effort = 150 cm = 1.5 m
the distance of the load = 50 cm = 0.5 m
The velocity ratio of the machine = 1.5/0.5
= 3
The mechanical advantage of the machine is calculated as;
M.A = Load/effort
M.A = 750 / 250
M.A = 3
The efficiency of the machine is calculated as;
E = (M.A / V.R) x 100%
E = (3/3) x 100% = 100%
Therefore, the efficiency of the machine is 100%
show that pv=nrt has the same unit with energy
Answer:
It is proved.
Explanation:
PV = n R T
where, P is the pressure, V is the volume, n is the number of moles, R is the gas constant, T is the absolute temperature.
Unit of pressure is Pascal= Newton/square meter = [tex][ML^{-1}T^{-2}][/tex]
Unit of volume is cubic meter = [tex][L^{3}][/tex]
So, the unit of P V
[tex][ML^{-1}T^{-2}] \times [L^{3}]\\\\[ML^2T^{-2}}[/tex]
[tex][ML^{2}T^{-2}][/tex]
It is same as the unit of energy.
hence proved.
Velocity is vector quantity because??
Velocity is vector quantity because it has both magnitude and direction.
Explanation:
velocity is a vector quantity because the person always returns to the original position,the motion would never result in a change in a position.
kettles heated on stoves used to be made of copper. was this a good choice?
Kettles heated on stoves are used to be made up of copper. This is because copper is a good conductor of heat and electricity.
Why copper is used in making kettles?Copper is used in making kettles. This is because copper is an excellent choice for a tea kettle as it is an excellent conductor of heat and electricity. This means that copper heats up quickly and evenly, making it ideal for the purpose of boiling water and preparing tea. Copper is also a durable material which can last for many years with proper care.
Copper kettles are polished from the outer surface as it is subject to corrosion that is caused by salts and sulfates. If the kettles are not cleaned completely, this corrosion, even as a slight film, will affect the taste of what is prepared in that copper kettle, giving a metallic sensation to taste.
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¿ Sobre que superficie se desplazara mas rápidamente un tejo, sobre cemento o sobre cerámica? ¿por que?
Answer:
cemento potque es plano
12. Which of these is more dense?
A. 10kg of a block of wood
B. 1kg of a block of styrofoam
C. 1kg of feathers
D. 10kg of feathers
E. 10kg of stryfoam
F. 1 kg of wood
Answer:
answer is E
Explanation:
If a planet has the same mass as the earth, but has twice the radius, how does the surface gravity, g, compare to g on the surface of the earth
Answer:
The surface gravity g of the planet is 1/4 of the surface gravity on earth.
Explanation:
Surface gravity is given by the following formula:
[tex]g=G\frac{m}{r^{2}}[/tex]
So the gravity of both the earth and the planet is written in terms of their own radius, so we get:
[tex]g_{E}=G\frac{m}{r_{E}^{2}}[/tex]
[tex]g_{P}=G\frac{m}{r_{P}^{2}}[/tex]
The problem tells us the radius of the planet is twice that of the radius on earth, so:
[tex]r_{P}=2r_{E}[/tex]
If we substituted that into the gravity of the planet equation we would end up with the following formula:
[tex]g_{P}=G\frac{m}{(2r_{E})^{2}}[/tex]
Which yields:
[tex]g_{P}=G\frac{m}{4r_{E}^{2}}[/tex]
So we can now compare the two gravities:
[tex]\frac{g_{P}}{g_{E}}=\frac{G\frac{m}{4r_{E}^{2}}}{G\frac{m}{r_{E}^{2}}}[/tex]
When simplifying the ratio we end up with:
[tex]\frac{g_{P}}{g_{E}}=\frac{1}{4}[/tex]
So the gravity acceleration on the surface of the planet is 1/4 of that on the surface of Earth.
What is meant by measurement? l
Answer:
The action of measuring the size, length, or amount of something, as established is called measurement.
Explanation:
“Measurement” is the act of determining a target's size, length, weight, capacity, or other aspect. ... To use measurement tools as necessary. It is also appropriate to say that measurement is done by a worker using a measurement system, and instrumentation is done by a technician.
4. A bullet of mass 30 g is fired from a rifle of mass 5kg at a speed of 259m/s.
a) What is the momentum of the rifle just after the bullet is fired?
b) What is the recoil velocity of the rifle?
Answer:
Rifle Momentum=7.77kg*m/s v'= 1.554 m/s
Explanation:
a) m1v1 + m2v2 = m1v1' + m2v2'
0+0 = 0.03*259 + P(rifle momentum)
solve for P
p= 7.77kg*m/s
b) 7.77= 5*v'
v'= 1.554 m/s
The momentum of the rifle just after the bullet is fired is 7.77 kg.m/s and the recoil velocity of the rifle at the time of firing is 1.554 m/s.
What is momentum?
Momentum of a particle is the product of the mass of the particle and its velocity. Momentum is a vector quantity. It has both the magnitude and direction of motion. According to the Newton's second law of motion, the rate of change of the momentum is equal to the force acting on the particle which is in motion.
Momentum can be calculated by the general formula
p = m.v
where, p = momentum of the particle,
m = mass of the particle,
v = velocity of the particle.
Rifle Momentum= mass × velocity
P = m × v'
a) m1v1 + m2v2 = m1v1' + m2v2'
0+0 = 0.03 × 259 + P(rifle momentum)
0 = 7.77 + P
P = 7.77kg.m/s
b) p = m × v
7.77= 5 × v'
v'= 1.554 m/s
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The acceleration of the car with two washers added to the string would be
Answer:
[tex]a=0.33\ m/s^2[/tex]
Explanation:
For washer 2,
v₁ = 0.13 m/s
v₂ = 0.36 m/s
t₁ = 1.92
t₂ = 2.61
We need to find the acceleration of waster 2.
[tex]a=\dfrac{v_2-v_1}{t_2-t_1}\\\\a=\dfrac{0.36-0.13}{2.61-1.92}\\\\a=\dfrac{0.23}{0.69}\\\\a=0.33\ m/s^2[/tex]
So, the acceleration of washer 2 is [tex]0.33\ m/s^2[/tex].
Answer:
.33
Explanation:
When applying an arm sling, the injured arm's hand should be placed in a ________ position in the sling, and above the level of the elbow.
Answer:
The answer is "thumb-up".
Explanation:
The sling often called the arm sling, is a solution for preventing either shoulder or elbow motion during healing. A triangle bandage could be constructed.
A sling is a strong tissue loop that descends from the head to hold the forearm. The armrests in the sling bent also at the elbow.
The injured hand of the forearm should be positioned inside the pin position in the joint above the level of the elbow when putting the forearm sling.
If a wire lies withina magnetic field what must be true for the magnetic field to produce an electric current in the wire
Answer:
The magnetic field through the wire must be changing
Explanation:
According to Faraday's law, the induced emf, ε in a metallic conductor is directly proportional to the rate of change of magnetic flux,Φ through it. This is stated mathematically as ε = dΦ/dt.
Now for the wire, the magnetic flux through it is given by Φ = ABcosθ where A = cross-sectional area of wire, B = magnetic field and θ = angle between A and B.
So, dΦ/dt = dABcosθ/dt
Since A and B are constant,
dΦ/dt = ABdcosθ/dt = -(dθ/dt)ABsinθ
Since dθ/dt implies a change in the angle between A and B, since A is constant, it implies that B must be rotating.
So, for an electric current (or voltage) to be produced in the wire, the magnetic field must be rotating or changing.
coulomb what is the meaning in physics??
Answer:
Coulomb, unit of electric charge in the metre- kilogram- second- ampere system, the basis of SI system of physics unit. The coulomb is defined as the quantity of electricity transported in one second by a current of one ampere.
A scientist wants to use a model to help present results of his detailed scientific investigation
4. Which of the following statement describes the particle model.
A. The average kinetic energy of the particles changes easily
B. All matter is made up of large triangular particles
C. There are no spaces between the particles
D. The average kinetic energy of all the particles remains constant
E.Other:
Define couple and give 2 examples
Answer:
Two equal and opposite parallel forces not acting along the same line, form a couple. A couple is always needed to produce the rotation.
For example, turning a key in a lock and turning a steering wheel.
The chart shows the speed at which light travels through different media.
In which medium would light have the longest wavelength?
- Water
- Air
- Glass
- Diamond
Answer:
Air.
Explanation:
To know which option is correct, let us consider the relationship between velocity and the wavelength of a wave. This is illustrated below:
Velocity, wavelength and frequency are related by the following equation:
Velocity = wavelength × frequency
v = λf
From the equation above, we can see clearly that the velocity is directly proportional to the wavelength.
This means that an increase in the wavelength will lead to an increase in the velocity and also, a decrease in the wavelength will lead to a decrease in the velocity.
Now, considering the table given in the question above, we can see that the wave has a higher speed in air. This simply means that the wave will also have a higher wavelength in air.
Thus, the correct answer to the question is: air
A shell is fired at an initial speed of 2500 m/s at an initial angle of 45 degrees. Find the shell's horizontal range and the amount of time the shell is in motion. (note that because it is fired from the ground to the ground, they displacement = 0.)
Answer:
d= 637323 meters
t= 360.5 seconds
Answer:
Explanation:
Since the height from which the shell was fired is the same as the height at which it lands (on the ground, to be specific), we will use the range equation. That is the only time you CAN use the range equation (when the initial height and the final height are exactly the same). The range equation is:
[tex]r=\frac{v_0^2sin(2\theta)}{g}[/tex] where v0 is the initial velocity, theta is the angle, and g is the pull of gravity (NOT negative). Filling in:
[tex]r=\frac{(1500)^2sin(9.0*10^1)}{9.8}[/tex] so, doing all that math gives us:
r = 6.4 × 10⁵ meters
A boat takes off from the dock at 2.5m/s and speeds up at 4.2m/s2 for 6.0 seconds how far has the boat traveled
Answer:
The answer is "91 m"
Explanation:
[tex]v_0 = 2.5 \ \frac{m}{s}\\\\a = 4.2\ \frac{m}{s^2}\\\\t = 6.0\ s\\\\\Delta x=?[/tex]
Using formula:
[tex]\Delta x = v_0 t +\frac{1}{2} at^2\\\\[/tex]
[tex]= 2.5 \times 6.0 +\frac{1}{2} \times 4.2 \times 6.0^2\\\\= 90.6\ m \approx 91\ m[/tex]
please help me with this question
Answer:
(4) A = 3 A, A₂ = 11 A
(5) 7 A
Explanation:
(4)
From the diagram,
A = 3+6+2
A = 11 A
V = A₂R
A₂ = V/R₂............ Equation 1
Given: V = 12 V, R₂ = 4 Ω
Substitute these values into equation 1
A₂ = 12/4
A₂ = 3 A
(5) Applying,
V = IR'
I = V/R'............ Equation 1
Where V = Voltage, I = cuurent, R' = total resistance.
But,
1/R' = (1/3)+(1/4)
1/R' = (3+4)/12
1/R' = 7/12
R' = 12/7 Ω
Given: V = 12 V
Substitute these values into equation 1
I = 12/(12/7)
I = 7 A
Therefore
A = 7 A
How does work affect energy between objects so it can cause a change in the form of energy?
A. Work transfers energy.
B. Work changes energy.
C. Work increases energy.
D. Work decreases energy.
A cycle travels along a circular track of diameter 42 m. Calculate the distance travelled and the displacement of the cycle in (a) Half round (b)One round.
please explain it to me clearly,its so confusing
i will give brainlist to the one who explains it clearly
Answer:
(a) i) The distance travelled by the cycle in half round is approximately 65.97 m
ii) The displacement is 42 m
(b) (i) The distance travelled in one round is approximately 131.95 m
(ii) The displacement of the cycle in one round is 0
Explanation:
The diameter of the track through which the cycle travels, D = 42 m
(a) i) Half round is the motion of half the length of the circular path
The distance travelled by the cycle in half round = The length of half the circular track = (1/2) × π × D
∴ The distance travelled by the cycle in half round = (1/2) × π × 42 m = 21·π m ≈ 65.97 m
ii) The displacement half round = The change in the location of the cycle = The difference between the start and stop locations of the cycle on a straight line after half round
The angle at the center of the circular path the cycle turns in half round = 180°
Therefore, the path between the start and stop location of the cycle in half round = The diameter of the circular track
The displacement of the cycle in half round = The diameter of the circular track = 42 m
(b) (i) The distance travelled in one round = The perimeter of the circular track = π·D
∴ The distance travelled in one round = π × 42 m ≈ 131.95 m
(ii) The displacement of the cycle in one round = The change in the location of the cycle
The start and stop location of the cycle after moving one round is the same, therefore, there is no change in the location of the cycle.
Therefore we have;
The displacement of the cycle in one round = 0 (no change in location of the cycle)
State any ten reasons why students in Uganda need to study physics.(use examples of the possible technological advancements which can be made using the knowledge of physics)
Answer:
The answer is "physics ".
Explanation:
Physics is the branch of science that addresses the properties of crystalline and its interaction with the fundamental elements of the universe. It covers subjects ranging in quantum mechanics with extremely little ones with quantum mechanics to the whole cosmos. You must be constant whether you like it or not, thus everyone must learn physics, irrespective of whether they're in Uganda, and plenty of other countries should have physics to dare study.
3.00 m^3 of water is at 20.0°C.
If you raise its temperature to
60.0°C, by how much will its
volume expand?
Water
ß = 207•10-6C-1
(Unit = m^3)
Answer:
9m^3
Explanation:
Given data
volume v1= 3m^3
volume v2= ???
Temperature T1= 20.0°C.
Temperature T2= 60.0°C.
Applying the relation for temperature and volume
V1/T1= V2/T2
substitute
3/20= V2/60
3*60= V2*20
180= 20*V2
180/20= V2
V2= 9m^3
Hence the final volume is 9m^3
What happens in a series circuit when more bulbs are added? (Example: I start out with a complete series circuit with 2 bulbs. Then I add in several more wires and several more bulbs & bulb holders. Now I have a complete series circuit with 5 bulbs).
Answer:
when we add elements in a series circuit the voltage across each element decreases
Explanation:
In a series circuit the current the whole circuit is the same, since there is only one path,
resistance is the sum of the resistance of each element
R_{eq} = ∑ R_i
if we write ohm's law
V = i R_{eq}
we substitute
V = i ∑ R_i
therefore the total voltage is
V = ∑ i R_i = ∑ V_i
With this expression we see that the voltage decreases as we place more elements in the series circuit.
Specifically when we fear two elements the voltage across each element is
V_i = V / 2
when we have 5 elements the voltage across each element is
V_i = V / 5
therefore when we add elements in a series circuit the voltage across each element decreases
how much of the electro magnetic spectrum is visible to us
Answer:
The entire rainbow of radiation observable to the human eye only makes up a tiny portion of the electromagnetic spectrum – about 0.0035 percent. This range of wavelengths is known as visible light.
Explanation:
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A student attaches a rope to a box and pulls the box up a ramp as shown below. The ramp has a rough surface. When
drawing the free body diagram for the box, the friction force should be directed:
O up and to the right
down and to the left
up and to the left
to the left
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A 0.15-mm-wide slit is illuminated by light of wavelength 462 nm. Consider a point P on a viewing screen on which the diffraction pattern of the slit is viewed; the point is at 26.9° from the central axis of the slit. What is the phase difference between the Huygens' wavelets arriving at P from the top and midpoint of the slit?
Answer:
[tex]\triangle \phi=461.5rad[/tex]
Explanation:
From the question we are told that:
Silt width [tex]w=0.15=>0.1510^{-3}[/tex]
Wavelength [tex]\lambda=462nm=462*10^{-9}[/tex]
Angle [tex]\theta=26.9[/tex]
Generally the equation for Phase difference is mathematically given by
[tex]\triangle \phi=\frac{2 \pi}{\lambda}(\frac{wsin\theta }{2})[/tex]
[tex]\triangle \phi=\frac{2 \pi}{462*10^{-9}}(\frac{0.1510^{-3}*sin 26.9 }{2})[/tex]
[tex]\triangle \phi=461.5rad[/tex]
[tex]\triangle \phi=146.89\pi[/tex]
What is the name of the Egyptian sun god, usually depicted as a hawk-headed man with a solar disk and cobra on his head
Answer: Re-Horakhty
Explanation:
He has a human body and a falcon head, he has a crown in form of a disk with a cobra on his head. Ra-Horakhty was thought of as the god of the rising sun.
Atoms contain both positive nuclei and a negative electron cloud. Which of the following would cause an attraction between two atoms?
A. The nucleus of one atom and the electron cloud another atom
B.The nucleus of one atom and the nucleus of another atom
C. The electron cloud of one atom and the electron cloud of another atom
D.None of these would cause an attraction between atoms
Answer:
Option (D)
Explanation:
A. The nucleus of one atom and the electron cloud of the another atom will not the cause of attraction.
B. The nucleus of one atom and the other atom will not cause the attraction.
C. The electron cloud of one atom and the electron cloud of the another will not cause attraction.
D. So, this option is correct.