Answer:
displacement=specific distance
*Velocity=∆displacement/time
*acceleration=∆velocity/time
Kevin used a pulley to lift a piano to the third floor of his apartment. His input work was 12,000 J and the output work was 10,000 J. What was the mechanical efficiency of the pulley?
A . 50%
B. 83.3%
C . 120%
D. 16.7%
Answer:
B
Explanation:
Eff = output work/input work ×100
Hence, Eff = 10000/12000 × 100
Eff = 83.3%
the direction of applied force has to be_____ to the distance in order to say work is done
Answer:
Explanation:
The direction of the applied force has to be parallel to the distance an object moved in order to say that work has been done.
WhAT is the change IN THE entropy of 2.0kg of h2o molecules when transform at a constant pressure of 1 atm from water at 100 degrees celcius to steam at the same tEMPERATURE?
Answer:
The entropy change is 45.2 kJ/K.
Explanation:
mass of water at 100 C = 2 kg
Latent heat of vaporization, L = 2260 kJ/kg
Heat is
H = m L
H = 2 x 2260 = 4520 kJ
Entropy is given by
S = H/T = 4520/100 = 45.2 kJ/K
The entropy change during the phase change of water from liquids to steam at constant pressure and same temperatures will be zero because, Δ T is zero here.
What is entropy?Entropy is a thermodynamic parameter determining the measure of randomness in a system. Entropy of a natural reaction or change is always increasing.
According to second third law of thermodynamics the entropy change of the universe is positive always. At constant pressure the entropy change a of substance of m g is written as:
ΔS = m Cp ln T2/T1.
Where Cp is the specific heat capacity at constant pressure.
Here, the initial temperature and final temperature is same 100 degree celsius. Thus T2/T1 becomes 1 and log 1 is zero. Therefore, the entropy change in this phase change is zero.
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What was the role of gravity in the formation of the solar system?
A. Gravity caused the solar system to separate into individual
celestial bodies
B. Gravity caused the solar system to move closer to the Sun.
C. Gravity caused the solar system to compress into one larger
mass
D. Gravity caused the solar system to expand from a central point.
Answer:
Approximately 4.6 billion years ago, the solar system was a cloud of dust and gas known as a solar nebula. Gravity collapsed the material in on itself as it began to spin, forming the sun in the center of the nebula. ... Small particles drew together, bound by the force of gravity, into larger particles.
the internal resistance of each of the following cells E1 and E2 shown in the figure above is 2ohms. calculate the total current in the circuit
Answer:
The total current in the circuit is 0.8 A.
Explanation:
internal resistance of each battery = 2 ohm
Total emf of the circuit, E = E1 + E2 = 2 = 2 = 4 V
Now total internal resistance is
[tex]r = \frac{2\times 2}{2 + 2}= 1 ohm[/tex]
Total resistance, R = 4 = 1 = 5 ohm
Let the current is I.
E = I R
4 = I x 5
I = 0.8 A
please answer me my question
25)Two forces are acting on a block in opposite directions as shown in the figure above
(a) Calculate the net force acting on the block.
(b) In which direction will the net force tend to move the object?
(c) Will any other force try to oppose the motion of the block?
[tex]\boxed{ \sf{Answer}} [/tex]
____________________
(a) A = 5 kgwt
B = 10 N
First convert 5 kgwt to N,
[tex]5 \times 9.8 \\ = 49 \: N[/tex]
Net force [the forces are acting in 2 opposite directions]
[tex]A - B \: \\ = 49 - 10 \\ = 39 \: N[/tex]
____________________
(b) Since, the force is greater by A ↦the block will move towards B, i.e, to the right.
____________________
(c) Frictional force will try to oppose the motion of the block but since A has greater force than B, the frictional force will be resisted.
____________________
ʰᵒᵖᵉ ⁱᵗ ʰᵉˡᵖˢ ツ
꧁❣ ʀᴀɪɴʙᴏᴡˢᵃˡᵗ2²2² ࿐
The particles of a substance stay close together but slide past one another as they move. When thermal energy is removed from the substance, the particles are forced into fixed positions by their attraction to one another. What change in state has occurred?
O A. Gas to solid
O B. Liquid to solid
O C. Solid to liquid
O D. Gas to liquid
Explanation:
The Answer is B.I think so may be it's wrong so kindly get any confirmation from your teacher about this
Imagine using brainly LOL COULDNT BE ME XD
Answer:
LOL! couldnt be me either bestieeeee
Answer:
-_-
Explanation:
i dont know What was XD??
20 kg rodsis on the edge of a 80 m high de What is the rodes gracional potencial energy?
Answer:
Gpe = 15680 Joules
Explanation:
Gravitational potential energy (GPE) is an energy possessed by an object or body due to its position above the earth.
Mathematically, gravitational potential energy is given by the formula;
G.P.E = mgh
Where;
G.P.E represents potential energy measured in Joules.
m represents the mass of an object.
g represents acceleration due to gravity measured in meters per seconds square.
h represents the height measured in meters.
Given the following data;
Mass = 20 kg
Height = 80 m
We know that acceleration due to gravity is equal to 9.8 m/s²
To find the gravitational potential energy;
Gpe = mgh
Gpe = 20 * 80 * 9.8
Gpe = 15680 Joules
Where are spores located on a fern? 1. On the root systems 2. In the flowers of the ferns 3. On the underside of the fronds 4. In the capsule of the sporophyte
1.the student measures the mass of a piece of metal.its mass is 146g.
(a) the volume of the piece of metal is 20cmcube. calculate the density of the metal .
(b) state the unit.
Answer:
7.3 g/cubic cm
Explanation:
You divide the mass by the volume to calculate the density of the metal.
146g ÷ 20cm³ = 7.3g/cm³
What what is the change in internal energy if 500 joule of heat is added to a system and 125 joule of work are done on a system
Answer:
DU = 375 Joules
Explanation:
Given the following data;
Quantity of heat = 500 Joules
Work done = 125 Joules
To find the change in internal energy;
Mathematically, the change in internal energy of a system is given by the formula;
DU = Q - W
Where;
DU is the change in internal energy.Q is the quantity of energy.W is the work done.Substituting into the formula, we have;
DU = 500 - 125
DU = 375 Joules
Cuộn dây có N = 1000 vòng, mỗi vòng có diện tích S = 20 cm2 đặt trong một từ trường đều. Trục của cuộn dây song song với vectơ cảm ứng từ của từ trường. Cho độ lớn B biến thiên, người ta thấy có suất điện động cảm ứng eC = 10V được tạo ra. Độ biến thiên cảm ứng từ là bao nhiêu trong thời gian ∆t = 10-2 s
determine the metacentric height of a cylinder of 4 m diameter and height of 4m floating in water with its axis vertical, if period of oscillation is 6 seconds
Answer:
-0.383 m
Explanation:
Diameter of cylinder = 4m therefore r = 2
height of cylinder ( H ) = 4 m
specific gravity = 0.6 ( assumed )
depth of immersion = 'h'
Determine the metacentric height
weight of cylinder in water = water displaced
= 0.6 * 1000 * πr^2* H = 1000 * πr^2* h
= 0.6 * 4 = h
∴ h = 2.4 m
hence the depth of center of buoyancy from free space = h /2 = 1.2 m
The metacentric height can be calculated using the formula below
Gm = Io / Vsubmerged - BG
attached below is the remaining solution
un litro de un gas es calentado a presión constante desde 20°C hasta 60°C que volumen final ocupará dicho gas?
Answer:
Final volume, V2 = 3 Litres
Explanation:
Given the following data;
Initial volume, V1 = 1 litre
Initial temperature, T1 = 20°C
Final temperature, T2 = 60°C
To find the final volume, we would use Charles' law;
Charles states that when the pressure of an ideal gas is kept constant, the volume of the gas is directly proportional to the absolute temperature of the gas.
Mathematically, Charles is given by;
V1/T1 = V2/T2
Making V2 as the subject formula, we have;
V1T2 = V2T1
V2 = (V1T2)/T1
Substituting into the formula, we have;
V2 = (1 * 60)/20
V2 = 60/20
Final volume, V2 = 3 Litres
A 20-N force acts on a 5-kg object at rest. How fast will
the object accelerate on a frictionless surface?
A. 15 m/s^2
B. 25 m/s^2
C. 4 m/s^2
D. 100 m/s^2
Answer:
C.
Explanation:
Force = Mass * Acceleration
So 20 = 5* Acceleration
4 = Acceleration
The acceleration of the object is 4 m/s².
To find the acceleration, the given values are:
Force = 20 N
Mass = 5 kg
Define acceleration.Definition:
As it was given as the values of Force and mass, here acceleration definition depends on the Newton's second law of motion.
Using the second law of motion, the force will be equal to the product of the mass and the acceleration.
As formula,
F = ma Newton
Here, to find acceleration,
a =f/ m
Substituting the values,
= 20 / 5
a = 4m/s².
So, the acceleration was 4 m/s². The Option C is the correct answer.
Learn more about acceleration,
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A sample of nitrogen gas is inside a sealed container. The volume of the container decreases while the temperature is kept constant. This is a ________ process.
a) isothermal
b) constant-volume
c) adiabatic
d) isobaric
Which object has potential energy but not kinetic energy?

A.
A battery in a pair of headphones

B.
A person riding an elevator upward

C.
A person climbing a ladder

D.
A car that is slowing down
Answer:
A.
A battery in a pair of headphones
Explanation:
Potenial energy - the energy possessed by a body by virtue of its position relative to others, stresses within itself, electric charge, and other factors.
Earth changes all the time making it a __ planet.
5. According to the law of reflection, the
is equal to the angle of incidence and a line drawn perpendicular to the reflecting surface.
O reflected ray
angle of reflection
O angle of refraction
Answer:
the answer is ....angle of reflection
An object is free falling near the surface of the earth. At a certain instant in time, it is falling downward at a rate 25.0 m/s. After 2.5 seconds, what are its acceleration and velocity?
Answers:
acceleration = 9.81 m/s^2velocity = 49.5 m/sThe values are approximate.
==========================================================
Explanation:
When near the surface of the earth, the acceleration of gravity is roughly 9.81 m/s^2. This means that after each second passes, the velocity increases by roughly 9.81 m/s.
After 2.5 seconds, the velocity increases by 2.5*9.81 = 24.525 m/s = 24.5 m/s
If it was already going 25.0 m/s, then it bumps up to 25.0+24.5 = 49.5 m/s which is also approximate.
The acceleration of gravity stays the same when the object is close to the surface of the earth, so it stays at roughly 9.81 m/s^2
Side note: I'm ignoring air resistance (aka air friction or drag) since that greatly complicates things, and we would need to know the shape and surface area of the object. The material type would also be relevant info as well.
What is the difference between heat capacity and specific heat capacity? I want the meaning please.
Answer:
The heat capacity of a body is defined as the heat required to raise it's temperature by me degree or one kelvin.while specific heat capacity of a substance is defined as the heat required to the temperature of a unit mass of it through one degree or one kelvin.
I hope it helps
what do you mean by supplementary quantities and its unit?
$ \large\boxed{ \sf \red{More ~Info :}}$
The units of supplementary quantities are dimensionless units.
[tex] \\ [/tex]
A stone is thrown vertically upwards with an initial velocity of 20m/sec. Find the maximum height ot reaches and the time taken by it to reach the height. (g=10m/s2)
plz short numerical ASAP
Answer:
The height reached is 20m, The time taken to reach 20m is 2 seconds
Explanation:
Observing the equations of motion we can see that the following equation will be most helpful for this question.
[tex]v^{2} = u^{2} + 2as[/tex]
We are given initial velocity, u
We know that the stone will stop at its maximum height, so final velocity, v
Acceleration, a
And we are looking for the displacement (height reached), s
Substitute the values we are given into the equation
[tex]0^{2} = 20^{2} + 2(10)s[/tex]
Rearrange for s
[tex]0^{2} -20^{2} =20s[/tex]
[tex]-400=20s[/tex]
[tex]\frac{-400}{20} =s[/tex]
s = -20 (The negative is just showing direction, it can be ignored for now)
The height reached is 20m
Use a different equation to find the time taken
[tex]s = vt - \frac{1}{2} at^{2}[/tex]
Substitute in the values we have
[tex]-20=(0)t - \frac{1}{2} (10)t^{2}[/tex]
Rearrange for t
[tex]-20 =0 -5 t^{2}[/tex]
[tex]\frac{-20}{-5} =t^{2}[/tex]
[tex]4 = t^{2}[/tex]
t = 2s
The time taken to reach 20m is 2 seconds
Pluto has a shape that is nearly round,and it orbits the sun,it has five known moons.why is it called a dwarf planet and not a planet?
There are three things needed to be classified as a planet.
Pluto meets 2 of the 3.
The one it does not meet is it doesn’t “clear the neighborhood” which means a planet needs to be gravitationally dominant over all objects around it. Meaning smaller bodies ( asteroids) would either combine with the larger body making it bigger or pushing them away ( out of their orbit) so they do not collide with the larger body.
16 100 g of water at 25 °C is poured into an insulating cup. 50 g of ice at 0 °C is added to the water.
The water is stirred until the temperature of the water has fallen to 0°C.
18 g of ice remains unmelted.
The specific heat capacity of water is 4.2 J /g °C.
Which value does this experiment give for the specific latent heat of fusion of ice?
Answer:
Q = Q
mcT = ml
100 x 4.2 x 25 = (50-18) l
l = 328
*Hope it helps*
The specific latent heat of fusion of the melted ice is 328.13 J/kg.
Conservation of energy
The specific latent heat of fusion of the melted ice is determined by applying the principle of conservation of energy as shown below;
Heat lost by the water = Heat gained by the ice
McΔθ = mL
where;
c is specific heat capacity of waterL is pecific latent heat of fusion of icem is mass of melted ice = 50 g - 18 g = 32 g(100)(4.2)(25) = (32)L
32L = 10500
L = 328.13 J/kg
Thus, the specific latent heat of fusion of the melted ice is 328.13 J/kg.
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Light of wavelength 530.00 nm is incident normally on a diffraction grating, and the first‑order maximum is observed to be 33.0∘ from the normal. How many slits per millimeter are marked on the grating?
Answer:
1028 slits/mm
Explanation:
We are given that
Wavelength of light, [tex]\lambda=530nm=530\times 10^{-9} m[/tex]
1nm=[tex]10^{-9} m[/tex]
[tex]\theta=33^{\circ}[/tex]
n=1
We have to find the number of slits per mm are marked on the grating.
We know that
[tex]dsin\theta=n\lambda[/tex]
Using the formula
[tex]dsin33^{\circ}=1\times 530\times 10^{-9}[/tex]
[tex]d=\frac{530\times 10^{-9}}{sin33^{\circ}}[/tex]
[tex]d=9.731\times 10^{-7} m[/tex]
1m=[tex]10^{3}mm[/tex]
[tex]d=9.731\times 10^{-7}\times 10^3[/tex]mm
[tex]d=0.0009731mm[/tex]
Number of slits=[tex]\frac{1}{d}[/tex]
Number of slits=[tex]\frac{1}{0.0009731}[/tex]/mm
Number of slits=1028/mm
Hence, 1028 slits/mm are marked on the grating.
Answer:
1027.6 lines per mm.
Explanation:
wavelength = 530 nm
order, m= 1
Angle = 33 degree
Let the slits per mm is 1/d.
So,
[tex]m \lambda = d sin A\\\\1\times 530\times 10^{-6} = d sin 33\\\\\frac{1}{d} = 1027.6 lines per mm[/tex]
1. How much heat energy ( Q ) is required to heat 2.0 kg of copper from 30.0 oC to 80.0 oC?
Answer:
Heat capacity, Q = 38500 Joules
Explanation:
Given the following data;
Mass = 2 kg
Initial temperature, T1 = 30°C
Final temperature, T2 = 80°C
Specific heat capacity of copper = 385 J/Kg°C
To find the quantity of heat required;
Mathematically, heat capacity is given by the formula;
[tex] Q = mcdt [/tex]
Where;
Q represents the heat capacity or quantity of heat.
M represents the mass of an object.
C represents the specific heat capacity of water.
dt represents the change in temperature.
dt = T2 - T1
dt = 80 - 30
dt = 50°C
Substituting the values into the formula, we have;
[tex] Q = 2 * 385*50[/tex]
Heat capacity, Q = 38500 Joules
What is the length of the y-component of the vector plotted below?
A. 1
B. 4
C. 2
D.3
Answer:
um .... D. D D D D D this should be it
