Answer:
A substance's basic heat of fusion is the amount of heat needed to transform a unit mass of the substance from liquid to gaseous at its boiling point. B)... A substance's latent heat is known as the amount of energy emitted or consumed when the substance changes states.
Explanation:
A car of mass 800kg is travelling at 10m/s. How much work must be done to stop it?
Answer:
80
Explanation:
800/10
=80
pls mark as brainliest
An Olympic skier moving at 20.0 m/s down a 30.0o slope encounters a region of wet snow, of
coefficient of friction μk = 0.740. How far down the slope does she go before stopping?
a.119 m
b.145 m
c.170 m
d.199 m
Answer:
Option B
Explanation:
Forces acting on the skier-
F1 [tex]= -mg sin(30)[/tex] down the slope
F2 [tex]= -mg cos(30)[/tex]
F3 = friction force [tex]= 0.74 mg cos(30)[/tex]
Net force, down the slope
[tex]= -mg sin(30)+ 0.74 mg cos(30)\\= mg(.74 cos(30)-sin(30))\\= 0.14mg\\= 1.38m[/tex]
Acceleration [tex]= F/m= 1.38[/tex] m/s2
Acceleration remains constant, initial speed is 20 m/s
Speed at time t is [tex]1.38t- 20[/tex] m/s
Distance down the slope at time t is [tex]0.69t^2- 20t[/tex]
When the skier stops, her speed is 0. Thus,
, [tex]1.38t- 20= 0\\t= 20/1.38\\= 14.5[/tex] seconds
Distance travelled in 14.5 seconds [tex]= (0.69)(14.52- 20(14.5)= -145 m[/tex](negative because it is down the slope).
Option B is correct
how much work is done in accelerating a 2000 kg car from rest to a speed of 30 m/s?
In a Young's double-slit experiment, two parallel slits with a slit separation of 0.165 mm are illuminated by light of wavelength 560 nm, and the interference pattern is observed on a screen located 4.05 m from the slits. (a) What is the difference in path lengths from each of the slits to the location of the center of a fifth-order bright fringe on the screen
Answer:
the difference in path lengths from each of the slits to the location of the center of a fifth-order bright fringe on the screen is 28 × 10⁻⁷ m
Explanation:
Given the data in the question;
slit separation d = 0.165 mm = 0.165 × 10⁻³ m
wavelength λ = 560 nm = 560 × 10⁻⁹ m
distance between the screen and slits D = 4.05 m
now,
for fifth-order bright fringe path difference = mλ
where m is 5
so, the difference in path lengths from each of the slits will be;
Δr = mλ
we substitute
Δr = 5( 560 × 10⁻⁹ m )
Δr = 28 × 10⁻⁷ m
Therefore, the difference in path lengths from each of the slits to the location of the center of a fifth-order bright fringe on the screen is 28 × 10⁻⁷ m
A string with a length of 6.2 m is vibrated at its natural frequency (first harmonic). What is the wavelength of the produced standing wave?
3.1 m
6.2 m
12.4 m
18.6 m
Answer:
12.4m
Explanation:
Given
Length of string = 6.2m
L = λ/2 (for natural frequency (first harmonic)
λ = 2L
λ = 2(6.2)
λ = 12.4m
Hence the wavelength of the produced standing wave is 12.4m
the electrostatic force between two objects is 40N. if the charge of one object is cut in half, and the distance is doubled, what is the new force?
Answer:
F1 = K Q1 Q2 / R1^2
F2 = K Q1 / 2 * Q2 / (2 R1)^2
F2 / F1 = 1/2 / 4 = 1/8
The new force is 5N (1/2 due to charge and 1/4 due to distance)
1. How fast is a radio wave traveling if it is 4.0 meters long and its frequency is
82 Hz?
Answer:
Speed = 328 m/s
Explanation:
Given the following data:
Wavelength = 4 m
Frequency = 82 Hz
To find the speed of the radio wave;
Speed = wavelength * frequency
Speed = 4 * 82
Speed = 328 m/s
Therefore, the radio wave is travelling at 328 meters per seconds.
Radio waves can be defined as an electromagnetic wave that has its frequency ranging from 30 GHz to 300 GHz and its wavelength between 1mm and 3000m. Therefore, radio waves are a series of repetitive valleys and peaks that are typically characterized of having the longest wavelength in the electromagnetic spectrum.
Question 3
By what volume would 25 L of alcohol increase if its temperature was
increased from 20°C to 30°C? (3 marks)
Answer:
V2 = 37.5 L
Explanation:
Given the following data;
Initial volume, V1 = 25 L
Initial temperature, T1 = 20°C
Final temperature,T2 = 30°C
To find the final volume V2, 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;
[tex] \frac {V}{T} = K[/tex]
[tex] \frac{V_{1}}{T_{1}} = \frac{V_{2}}{T_{2}} [/tex]
Making V2 as the subject formula, we have;
[tex] V_{2}= \frac{V_{1}}{T_{1}} * T_{2}[/tex]
[tex] V_{2}= \frac{25}{20} * 30 [/tex]
[tex] V_{2}= 1.25 * 30 [/tex]
V2 = 37.5 L
Explain how to make aluminum magnetic
Answer:
Use some Glue.. . . Aluminium is not magnetic, so your magnet can't sticl to aluminium without using Glue. You cannot get a magnet to stick to aluminum, no matter how hard you try. Aluminum is diamagnetic, which means it repels a magnetic field.
Explanation:
Hope It Help
brainliest please
13. The percent of Earth's surface covered by high clouds
in January 1987 was closest to which of the following?
A. 13.09
B. 13.5%
C. 14.0%
D. 14.5%
16. Which of the following figures best represents the
monthly average cover of high. middle, and low clouds
in January 19922
E.
H.
cloud cover
okud cover
middle cloud
high clouds
high cloud
low clouds
low clouds
midle clouds
G.
J.
14. Based on Table I. a cosmic ray flux of 440.000 parti-
cles/m he would correspond to a cover of low clouds
that is closest to which of the following?
F. 28.75
G. 29.09
H. 29.35
J. 29.6%
ckud cover
cloud cover
high clouds
low clouds
middle cloud
high clouds
middle clouds
low clouds
Water is to be heated from 10°C to 80°C as it flows through a 2-cm-internal-diameter, 13-m-long tube. The tube is equipped with an electric resistance heater, which provides uniform heating throughout the surface of the tube. The outer surface of the heater is well insulated, so that in steady operation all the heat generated in the heater is transferred to the water in the tube. If the system is to provide hot water at a rate of 5 L/min, determine the power rating of the resistance heater. Also, estimate the inner surface temperature of the pipe at the exit.
Answer:
- the power rating of the resistance heater is 24139.5 W
- the inner surface temperature of the pipe at the exit is 96.34°C
Explanation:
Given the data in the question;
Flow rate of water in the tube V" = 5L/min = 8.333 × 10⁻⁵ m³/s
The water is to be heated from 10°C to 80°C;
so Average or mean temperature [tex]T_{avg[/tex] will be;
[tex]T_{avg[/tex] = (T₁ + T₂) / 2 = (10 + 80) / 2 = 90/2 = 45°C
Now, from the Table " Properties of Water " at average temperature;
at [tex]T_{avg[/tex] = 45°C
density p = 990.1 kg/m³
specific heat [tex]C_p[/tex] = 4180 J/kg-k
thermal conductivity k = 0.637 W/m-°C
Now, we determine the mass flow;
m" = pV"
we substitute
m" = 990.1 × 8.333 × 10⁻⁵
m" = 0.08250 kg/s
we know that the power rating of the resistance heater is equal to the heat transfer rate to the water;
Q' = m"[tex]C_p[/tex]( T₂ - T₁ )
we substitute
Q' = (0.08250 × 4180 ) ( 80 - 10 )
Q' = 344.85 × 70
Q' = 24139.5 W
Hence, the power rating of the resistance heater is 24139.5 W
Next, we determine the average velocity of water in the tube;
[tex]V_{avg[/tex] = V" / [tex]A_c[/tex]
[tex]V_{avg[/tex] = V" / ( [tex]\frac{1}{4}[/tex]πD² )
given that; flows through a 2-cm-internal-diameter; D = 0.02 m
we substitute
[tex]V_{avg[/tex] = (8.333 × 10⁻⁵) / ( [tex]\frac{1}{4}[/tex]π × (0.02)² )
[tex]V_{avg[/tex] = (8.333 × 10⁻⁵) / ( 3.14159 × 10⁻⁴ )
[tex]V_{avg[/tex] = 0.265 m/s
Also, from table " saturated water property table "
At 45°C
viscosity μ = 0.596 × 10⁻³ kg/m-s
Prandtl number Pr = 3.91
Now, we determine the kinematic viscosity
v = μ / p
we substitute
v = ( 0.596 × 10⁻³ ) / 990.1
v = 6.01959 × 10⁻⁷ m²/s
so, Reynolds number in the flow region will be;
Re = ([tex]V_{avg[/tex] × D) / v
we substitute
Re = ( 0.265 × 0.02) / (6.01959 × 10⁻⁷)
Re = 8804.586
we can see that our Reynolds number ( 8804.586 ) more than 2300 and less than 10,000.
Hydraulic and thermal entry length are equal in this flow region,
such that;
[tex]L_h[/tex] = [tex]L_t[/tex]
⇒ 10 × D = 10 × 0.02 = 0.2 m
we can see that the entry length ( 0.2 m ) is smaller than the given length ( 13 m ) in the question; the flow is a turbulent flow.
So we the Nuddelt number
Nu = [tex]0.023Re^{0.8} Pr^{0.4[/tex]
Nu = 0.023 × [tex]8804.586^{0.8[/tex] × [tex]3.91^{0.4[/tex]
Nu = 56.8
Hence, the heat transfer coefficient h will be;
h = [tex]\frac{k}{D}[/tex] × Nu
we substitute
h = [tex]\frac{0.637}{0.02}[/tex] × 56.8
h = 31.85 × 56.8
h = 1809.1 W/m²-°C
Now, area of the heat transfer will be
A[tex]_s[/tex] = πDL
we substitute
A[tex]_s[/tex] = π × 0.02 × 13
A[tex]_s[/tex] = 0.8168 m²
Finally we determine the inner temperature of the pipe at exit. using the relation;
Q' = hA[tex]_s[/tex]( T₃ - T₂ )
we substitute
24139.5 = 1809.1 × 0.8168( T₃ - 10 )
24139.5 = 1477.67288( T₃ - 80 )
24139.5 = 1477.67288T₃ - 118213.8304
24139.5 + 118213.8304 = 1477.67288T₃
1477.67288T₃ = 142353.3304
T₃ = 142353.3304 / 1477.67288T
T₃ = 96.34°C
Therefore, the inner surface temperature of the pipe at the exit is 96.34°C
The photo shows a pair of figure skaters performing a spin maneuver. The
axis of rotation goes through the left foot of the skater on the left. What
action could increase the pair's angular velocity?
An action which could increase the pair's angular velocity is the figure skater on the left pointing his right arm down instead of up.
What is angular velocity?Angular velocity simply refers to the rate of change of angular displacement of a physical object (body) with respect to time.
This ultimately implies that, angular velocity is a measure of how fast and quickly a physical object (body) rotates with respect to another point or how its angular displacement (position) changes with respect to time.
In this scenario, an action which could increase the pair's angular velocity is when the figure skater on the left points his right arm down instead of up.
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the skater on the left pulls the skater on the right closer to him
Explanation:
apex bliches
Exposure to a sufficient quantity of ultraviolet will redden the skin, producing erythema - a sunburn. The amount of exposure necessary to produce this reddening depends on the wavelength. For a 1.0 cm2 patch of skin, 3.7 mJ of ultraviolet light at a wavelength of 254 nm will produce reddening; at 300 nm wavelength, 13 mJ are required. Part A What is the photon energy corresponding to each of these wavelengths
Answer:
Energy = 7.83 x 10⁻¹⁹ J
Energy = 6.63 x 10⁻¹⁹ J
Explanation:
The energy of a photon in terms of wavelength can be calculated by the following formula:
[tex]Energy = \frac{hc}{\lambda}\\[/tex]
where,
h = Plank's Constant = 6.63 x 10⁻³⁴ Js
c = speed of light = 3 x 10⁸ m/s
λ = wavelength of light
Now, for λ = 254 nm = 2.54 x 10⁻⁷ m:
[tex]Energy = \frac{(6.63\ x\ 10^{-34}\ Js)(3\ x\ 10^8\ m/s)}{2.54\ x\ 10^{-7}\ m}\\[/tex]
Energy = 7.83 x 10⁻¹⁹ J
Now, for λ = 300 nm = 3 x 10⁻⁷ m:
[tex]Energy = \frac{(6.63\ x\ 10^{-34}\ Js)(3\ x\ 10^8\ m/s)}{3\ x\ 10^{-7}\ m}\\[/tex]
Energy = 6.63 x 10⁻¹⁹ J
How efficient are the small and large scale solar-power systems used in individual homes and industrial settings?
Plz someone help me
Answer:
I study physics too, want me to study with you?
describe the concept of force represent it quantiatively and derive unit of force
important please answer it as the question says and only if you know the answer
[tex]\bcancel{\huge\red{\fbox{\tt{࿐αɴѕωєя࿐}}}}[/tex]
Force is defined as the rate of change of momentum. For an unchanging mass, this is equivalent to mass x acceleration. So, 1 N = 1 kg m s-2, or 1 kg m/s2.
Which wave has the smallest wave
period? What is its period?
Answer:
C
Explanation:
The said wave takes the shortest time to move/get transmitted
PLEASE HELP
A ball, 1.8 kg, is attached to the end of a rope and spun in a horizontal circle above a student's head. As the student rotates the ball in a horizontal clockwise circle their lab partner counts 53 rotations in one minute. What is the ball's angular velocity in radians per second?
Answer:
The angular speed of the ball in radians per second is 5.55 rad/s.
Explanation:
Given;
mass of the ball, m = 1.8 kg
number of the ball's rotation per minute, n = 53 RPM
The angular speed of the ball in radians per second is calculated as follows;
[tex]\omega = 53\frac{rev}{\min} \times \frac{2\pi \ rad}{1 \ rev} \times \frac{1\min}{60 \ s } \\\\\omega = 5.55 \ rad/s[/tex]
Therefore, the angular speed of the ball in radians per second is 5.55 rad/s.
Roland Incorporated manufactures and sells portable hair dryers. If the price of a hair dryer is $ 127.00, then the company sells 116 hair dryers per week, and the elasticity of demand is −0.463. Assume that the demand function is differentiable and that the only time the company sells exactly 116 hair dryers per week is when the price of a hair dryer is $ 127.00. Given this situation, which of the following do you know MUST be true?
a. The marginal revenue is negative when Roland sells 144 driers per week.
b. The marginal profit is negative when Roland sells 144 driers per week.
c. The marginal profit is positive when Roland sells 144 driers per week.
d. The marginal revenue is positive when Roland sells 144 driers per week.
Answer:
The marginal revenue is positive when Roland sells 144 driers per week ( D
Explanation:
Elasticity of demand = -0.463
P = $127
116 hair dryers sold per week ( q )
demand function is differentiable
prove the true statement below
Revenue = price per unit * quantity
determine the Marginal revenue = dr / dq
∴ MR = P + q dp/dq
price elasticity of demand E(p) = - dq / dp * p/q
where : E ( p ) = - 0.463 , q = 116 , p = $127
q * dp/dq = P / 0.463
∴ MR = P * 1.463 / 0.463
= 127 * 3.16 = $401.32
since the Marginal revenue > 0 HENCE The marginal revenue will be positive when Roland sells 144 driers per week.
What is a centripetal acceleration of a greyhound running on a circular track with a radius of 50 m at 12.5 m/s
Answer:
Centripetal acceleration = 3.125 m/s²
Explanation:
Given the following data;
Radius, r = 50 m
Velocity, V = 12.5 m/s
To find the centripetal acceleration;
Centripetal acceleration = Velocity²/radius
Centripetal acceleration = 12.5²/50
Centripetal acceleration = 156.25/50
Centripetal acceleration = 3.125 m/s²
Therefore, the centripetal acceleration of the greyhound running on a circular track is 3.125 meters per seconds square.
Give me four reasons pluto is a cool planet / dwarf planet
How does a wind turbine make electricity?
1) The wind turns a generator inside.
2) Magic
3) Waves turn the generator.
4) Hamster turns the generator.
Answer:
1
Explanation:
Wind power is considered a renewable energy source.
O True
O False
Answer:
True
Explanation:
Answer:
your answer is true hope this helps
A long, uninsulated steam line with a diameter of 89 mm and a surface emissivity of 0.8 transports steam at 200C and is exposed to atmospheric air and large surroundings at an equivalent temperature of 20C. (a) Calculate the heat loss per unit length for a calm day. (b) Calculate the heat loss on a breezy day when the wind speed is 8 m/s. (c) For the conditions of part (a), calculate the heat loss with a 20-mm-thick layer of insulation (k 0.08 W/m K). Would the heat loss change significantly with an appreciable wind speed
Answer:
[tex]Q_net=534.67\frac{w}{m}[/tex]
Explanation:
From the question we are told that:
Steam line diameter [tex]D=89mm \approx 0.089m[/tex]
Surface emissivity [tex]\mu=0.8[/tex]
Steam temp [tex]T_s=200\textdegree C \approx 200+273=473k[/tex]
Surrounding temp [tex]T_a=20 \textdegree C \aprrox 20+273= 293k[/tex]
Generally the equation for heat loss per unit length due to radiation [tex]Q_{net}[/tex] is mathematically given by
[tex]Q_net=\sigma*\mu>(\pi *d)*(T_s^4-T_a^4)[/tex]
[tex]Q_net=5.6*10^8*0.8*(\pi *0.089)*(473^4-293^4)[/tex]
[tex]Q_net=534.67\frac{w}{m}[/tex]
name the three major types of clouds
Answer:
Cumulus, Stratus, and Cirrus. There are three main cloud types.
Explanation:
hopes it help^_^
Does an infrared wave or an x-ray travel faster in the vacuum of space?
Answer:
All electromagnetic radiation, of which radio waves and X-rays are examples, travels at the speed c in a vacuum. The only difference between the two is that the frequency of X-rays is very much higher than radio waves
45
А ______ is a solid, liquid or gas that a wave travels through.
Answer:
medium
Explanation:
I am not really sure
Part C
Now vary the mass of the skateboarder. Change the mass slider to the lowest mass. Repeat the investigation using the
steepest ramp. How does changing the mass of the skateboarder affect his kinetic energy on a given ramp? How does it
affect his speed? Remember to use the pause button to clearly see his energy and speed. Repeat your trials as many
times as needed.
Answer:
When mass increases, kinetic energy also increases. Changing mass doesn’t affect his speed on a given ramp.
Explanation:
Answer:
When mass increases, kinetic energy also increases. Changing mass doesn’t affect his speed on a given ramp.
Explanation:
pluto
A water pipe having a 4.00 cm inside diameter carries water into the basement of a house at a speed of 1.00 m/s and a pressure of 167 kPa. The pipe tapers to 1.4 cm and rises to the second floor 7.8 m above the input point. What is the speed at the second floor
Answer:
[tex]8.16\ \text{m/s}[/tex]
Explanation:
[tex]d_1[/tex] = Initial diameter = 4 cm
[tex]v_1[/tex] = Initial velocity = 1 m/s
[tex]d_2[/tex] = Final diameter = 7.8 m
[tex]v_2[/tex] = Final velocity
[tex]A[/tex] = Area = [tex]\pi\dfrac{d^2}{4}[/tex]
From the continuity equation we get
[tex]A_1v_1=A_2v_2\\\Rightarrow \pi\dfrac{d_1^2}{4}v_1=\pi\dfrac{d_2^2}{4}v_2\\\Rightarrow v_2=\dfrac{d_1^2}{d_2^2}v_1\\\Rightarrow v_2=\dfrac{4^2}{1.4^2}\times 1\\\Rightarrow v_2=8.16\ \text{m/s}[/tex]
The speed of water at the second floor is [tex]8.16\ \text{m/s}[/tex].
the titan mission scheduled for 2026 is a reconnaissance to explore the origin of life true or false
Answer:
its true
Explanation:
The titan mission scheduled for 2026 is a reconnaissance to explore the origin of life. Because, some scientific studies based on titan has showed that there is the presence of some biomolecules. Hence, the statement is true.
What is titan mission ?The distinctive, abundantly organic planet of Titan is where we will travel next in the solar system, according to NASA. The Dragonfly expedition will fly numerous sorties to sample and inspect locations around Saturn's icy moon, advancing our hunt for the components of life.
In 2026, Dragonfly will take off, and it will land in 2034. The rotorcraft will travel to a great number of Titan's promising sites in search of prebiotic chemical processes that are similar to those on Titan and Earth.
Dragonfly, which has eight rotors and flies like a big drone, is the first multi-rotor vehicle NASA will operate for science on another world. To become the first spacecraft to ever fly its full science payload, it will take advantage of Titan's dense atmosphere, which is four times denser than Earth's. Hence, the statement is true.
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Wind power produces a lot of air pollution.
O True
O False
Answer:
Wind is a renewable energy source. Overall, using wind to produce energy has fewer effects on the environment than many other energy sources. Wind turbines do not release emissions that can pollute the air or water (with rare exceptions), and they do not require water for cooling.
Explanation: