A train 90m long stops in a train station with its front buffers in line with a lamp post on the platform. Later it starts off with an average acceleration of 0.45m/s. What will be its speed in kilometers per hour when the tail buffers pass the lamp post P?
Answer:
The speed of the train when the tail buffers pass the lamp post is 9 m/s
Explanation:
The given parameters are;
The length of the train = 90 m
The initial velocity of the train, u = 0
The average acceleration of the train, a = 0.45 m/s²
When the tail buffer pass the lamp post, P, we have;
The distance travelled, s = The length of the train = 90 m
The kinematic equation of motion is given as follows;
v² = u² + 2·a·s
Where;
v = The speed of the train when the tail buffers pass the lamp post
∴ v² = 0² + 2 × 0.45 m/s² × 90 m = 81 m²/s²
Therefore;
v = √(81 m²/s²) = 9 m/s
The speed of the train when the tail buffers pass the lamp post, v = 9 m/s.
help with this physics question please :)
Answer:
is that rm in you profile pic
Help me frfr I don’t understand
The points are
(1,10)
(6,0)
[tex]\boxed{\sf slope(m)=\dfrac{y_2-y_1}{x_2-x_1}}[/tex]
[tex]\\ \sf\longmapsto m=\dfrac{0-10}{6-1}[/tex]
[tex]\\ \sf\longmapsto m=\dfrac{-10}{5}[/tex]
[tex]\\ \sf\longmapsto m=-2[/tex]
Write down the role played by four digestive juices in digestion and the
organs which secrete them.
Answer:
Digestive juices secreted by various organs such as salivary glands in the mouth, stomach, liver and pancreas help in the process of digestion of food. Saliva secreted by the salivary glands in the mouth aids in the breakdown of starch present in the food to simple sugar
Explanation:
Why is it difficult to maintain constant speed of a vehicle?
Answer:
The road surface is always rough, so the frictional force between the tires and the road surface make it difficult to maintain constant speed because acceleration always changes.
A ferrari has a mass of 1485kg.what is it's weight on Earth
F = m · g
m = 1485 kg
g = 10 N/kg
F = 1485 kg · 10 N/kg = 14 850 N = 14,85 kN
Answer: The weight on Earth is 14,85 kN.
6.
For a given prism the angle of incidence is changed from 0° and 90', the angle of deviation [ ]
b) decreases
c) first decreases and then increases
d) first increases and then decreases
a) increases
Answer:
increase
Explanation:
please mark as brainlyest
Answer
A.Increses
Explanation:
Why do scientists not use US customary units when reporting their data?
numerical filing method is more scientific why give me 4 reason
Answer:
Numerical Methods are mathematical way to solve certain problems.Whether the equations are linear or nonlinear, efficient and robust numerical methods are required to solve the system of algebraic equations.
Analytical solutions are exact solutions based on mathematical principles.
However, the governing partial differential equations of fluid flow are complex and cannot be solved by analytical means. The partial differential equations are therefore converted into a system of algebraic equations that are subsequently solved through numerical methods to provide approximate solutions to the governing equations.
Although we rarely reach on exact answer , we can get really close to the exact answer much quicker than solve analytically.
Answer:
oh my god
Explanation:
how long answer is this
.
What is the equation for work?
Work = force / distance
Work = force - distance
Work = force + distance
Work = force * distance
Answer:
Work = F X D
Explanation:
Work (J) equals Force (N) multiplied by Distance (M)
A particular electric car is supplied with 300 kJ of chemical energy by the battery. Of this, a total of 70.5 kJ of energy is wasted as heat.
Calculate the overall efficiency of the electric car.
Supplied energy=300kJ
Wasted energy=70.5JUsed energy:-
[tex]\\ \sf\longmapsto 300-70.5=229.5kJ[/tex]
We know
[tex]\boxed{\sf Efficiency=\dfrac{Used\:Energy}{Supplied\:Energy}\times 100}[/tex]
[tex]\\ \sf\longmapsto Efficiency=\dfrac{229.5}{300}\times 100[/tex]
[tex]\\ \sf\longmapsto Efficiency=\dfrac{229.5}{3}[/tex]
[tex]\\ \sf\longmapsto Efficiency=76.5\%[/tex]
The overall efficiency of the electric car = 76.5 %
To find the efficiency the given values are:
Energy supplied = 300 kJ
Energy wasted = 70.5 kJ
Define efficiency and calculate the value of efficiency.In the system the output energy is compared to the input energy is known as efficiency. That can be written as percentage ratio of output energy to the input energy.
Formula of efficiency is,
Efficiency = ( E out / E in ) × 100
Here, Energy supplied = 300 kJ
so, energy used = Energy supplied - Energy wasted
= 300 - 70.5
= 229.5 kJ
Thus, substituting E out = 300 kJ , E in = 229.5 kJ
Efficiency = ( 229.5 / 300 ) ×100
= 229.5 / 3
= 76.5
Hence, The overall efficiency of the electric car is 76.5 %
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Invisible damage to the body resulting from repeating a movement often is a
A cricketer throws a ball sideways with an initial velocity of 30 m/s. She releases the ball from a height of 1.3m. Calculate how far the ball travels before hitting the ground.
Answer:
78.34
Explanation:
1.3/30=78.3m
Which is an outer planet?
Answer:
pluto
Explanation:
Dwarf because it is very minut
Answer:
I think Saturn.
Explanation:
I think the inner planets are Mercury, Venus, Earth and Mars whereas the outer ones are Jupiter, Saturn, Uranus and Neptune.
Calculate the upthrust on a object immersed in water if the object displace water of mass 2 kg.(g=9.8m/s²)
Thrust is force
Mass=2kgAcceleration due to gravity=g=9.8m/s^2Using Newtons Second law
[tex]\boxed{\sf Force=Mass\times Acceleration}[/tex]
[tex]\\ \qquad\quad\sf{:}\dashrightarrow Thrust=2(9.8)[/tex]
[tex]\\ \qquad\quad\sf{:}\dashrightarrow Thrust=19.6N[/tex]
We have that the the upthrust on a object immersed in water is
[tex]U=19.6N[/tex]
From the Question we are told that
mass= 2kg
Gravity g=9.8m/s^2
Generally the equation for the upthrust is mathematically given as
[tex]U=mg[/tex]
Therefore
[tex]U=2*9.8[/tex]
[tex]U=19.6N[/tex]
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20. A semiconductor is a
crystalline solid that conducts current under any condition
metallic solid that conducts current under any condition
metallic solid that conducts current under certain conditions
crystalline solid that conducts current under certain conditions
Answer:
D. crystalline solid that conducts current under certain conditions
Explanation:
Semiconductors are crystalline solids that has the ability to conduct electrical currents but on certain conditions e.g heat. The conduction of semiconductors is less than that of conductors (metals) but more than insulators (nonmetals), hence, they are said to be intermediates of conductors and insulators in terms of electrical conductivity.
Examples of semiconductors are silicon, boron, carbon, germanium, arsenic etc.
cho 11,2 lit hỗn hợp gồm metan và etilen tác dụng với dung dịch brom. sau phản ứng xảy ra toàn thấy có chất khí thoát ra và 40 gam brom tham gia phản ứng .
a) viết phương trình phản ứng xảy ra
b) tính thành phần phần trăm thể tích mỗi chất trong hỗn hợp
c) đốt cháy toàn bộ thể tích khí thoát ra sau đó cho chất khí thu được tác dụng với 100ml dung dịch Ca(OH)2 1,25 M. tính khối lượng chất thu được sau phản ứng . biết metan ko tác dụng với brom , các chất khí đo ở điều kiện tiêu chuẩn
can someone please help me with a and b? what do they mean by amplitude?
Explanation:
first answer is that the to and fro movement of a pendulum is known as amplitude
importance of estimation in our lives
Why do scientists not use US customary units when reporting their data?
One of the scientist's jobs is to report the results of his experiments to all the other scientists in the world.
There isn't a single real science shop anywhere in the world that uses the US customary system of units. Not one.
Even in the measly three countries that use it for measuring carpet, pumping gas, and weighing fish ... Myanmar, Liberia, an the USA ... the scientists do their work in the SI/MKS/metric system.
The sky is blue because: Select one: a. the index of refraction for air is slightly larger for blue than for red b. atomic hydrogen is blue c. air molecules tend to polarize light along a horizontal axis d. oxygen and nitrogen molecules are small compared to the wavelengths of visible light e. oxygen molecules have a lower energy ground state than nitrogen molecules
Answer:
a. the index of refraction for air is slightly larger for blue than for red
A car has a mass of 2000 kg. While it is traveling along a perfectly flat road, it goes around an unbanked turn that has a radius of 40.0 m. The coefficient of static friction between the car tires and the road is 0.500. The car travels successfully around the turn at a constant speed of 10.0 m/s. Calculate the magnitude of the car's acceleration as it goes around the turn. _______ m/s^2
Answer:
2.5 m/s²
Explanation:
The given parameters are;
The mass of the car, m = 2,000 kg
The radius of the car, r = 40.0 m
The coefficient of friction between the car tires and the road, μ = 0.500
The constant speed with which the car moves, v = 10.0 m/s
The normal reaction of the road on the car, N = The weight of the car;
∴ N = m × g
Where;
g = The acceleration due to gravity ≈ 9.81 m/s²
N ≈ 2,000 kg × 9.81 m/s² = 19,620 N
The frictional force, [tex]F_f[/tex] = μ × N
The centripetal force, [tex]F_c[/tex] = m·v²/r
The car moves without slipping when [tex]F_f[/tex] = [tex]F_c[/tex]
Therefore, [tex]F_f[/tex] = 0.500 × 19,620 N = 2,000 kg × [tex]v_{max}[/tex]²/40.0 m
∴ [tex]v_{max}[/tex] = √(0.500 × 19,620 N × 40.0 m/2,000 kg) ≈ 14.007 m/s
Therefore, the velocity with which the car moves, v < [tex]v_{max}[/tex]
The cars centripetal acceleration, [tex]a_c[/tex] = v²/r
∴ [tex]a_c[/tex] = (10.0 m/s)²/40.0 m = 2.5 m/s²
The cars centripetal acceleration as it goes round the turn, [tex]a_c[/tex] = 2.5 m/s².
An object moving north with an initial velocity of 14 m/s accelerates 5 m/s2 for 20 seconds. What is the final velocity of the object?
39 m/s
90 m/s
114 m/s
414 m/s
Answer:
option C
Explanation:
Final velocity of the object is 114 m / s. Hence, final velocity of the object is 114 m / s.
A sound frequency 100Hz and wavelength 3.34m is travelling through air, calculate the Velocity of sound in air.
Answer:
334m/s
Explanation:
If you take the data you gave and insert it into the equation f=v/λ the frequency would come out to be 3.34m
334 m/s is the Velocity of sound in air.
What is the velocity of a wave?Wave velocity in common usage refers to speed, although, properly, velocity implies both speed and direction.
The velocity of a wave is equal to the product of its wavelength and frequency (number of vibrations per second) and is independent of its intensity.
Mathematically , v=fλ
According to the question,
Sound frequency (f) = 100Hz
Wavelength (λ)= 3.34m
Computing the values in the formula,
v=fλ
v = 100Hz x 3.34m
v= 334m/s
Therefore,
Velocity of sound in air is 334 m/s.
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HELP me
Which sentence best describes how the horse is doing work?
A It is using motion to transfer energy and force away from the heavy object
B it is using force to apply power and decrease the energy of the heavy object
C it is using energy to apply the force needed to move the object over a distance
D it is using power to force the heavy object to move over A certain distance
Which type of reactions usually happens slowest?
Answer:
option b is correct..................
A hockey puck has a mass of 0.21 kg. If the hockey puck
is moving with 74 J of kinetic energy, what is its speed?
Show all your work.
Answer:
v = 26.54 m/s
Explanation:
Given that,
The mass of a hockey puck, m = 0.21 kg
The kinetic energy of the hockey puck, E= 74 J
We need to find the speed of the hockey puck. Let the speed is v. We know that, the kinetic energy is given by :
[tex]E=\dfrac{1}{2}mv^2[/tex]
Where
v is the speed
So,
[tex]v=\sqrt{\dfrac{2E}{m}} \\\\v=\sqrt{\dfrac{2\times 74}{0.21}} \\\\v=26.54\ m/s[/tex]
So, the speed of the hockey puck is 26.54 m/s.
calculate the potential energy stored in a meta ball of mass of 80 kg kept at a height of 15m from the earth surface . What will be the potential energy when the metal ball is kept on the earth surface Take (g- 9.8 m/s]
Answer:
11760 J
Explanation:
cuz potential engery is PE = MHG
SO 80×15×9.8= 11760 J
Answer:
11769j
Explanation:
here,
mass(m)=80 kg
height(h)=15m
acceleration due to gravity(g)=9.8m/s^2
now,
potential energy = m×g×h
= 80×9.8×15
= 11760j
A girl is travelling on her bike at a speed 2.59 m/s. If the
girl and her bike have a kinetic energy of 190 J, what is
the combined mass of the girl and her bike? Show all
your work
Answer:
Mass, m = 146.72 kilograms
Explanation:
Given the following data;
Kinetic energy = 190 J
Velocity = 2.59 m/s
To find the combined mass of the girl and her bike;
Kinetic energy can be defined as an energy possessed by an object or body due to its motion.
Mathematically, kinetic energy is given by the formula;
K.E = ½mv²
Where;
K.E represents kinetic energy measured in Joules.
M represents mass measured in kilograms.
V represents velocity measured in metres per seconds square.
190 = ½*m*2.59
Cross-multiplying, we have:
380 = 2.59m
Mass, m = 380/2.59
Mass, m = 146.72 kilograms
Define measurement with examples.
Explanation:
Measurement is defined as the act of measuring or the size of something. An example of measurement means the use of a ruler to determine the length of a piece of paper. An example of measurement is 15" by 25". ... The dimension, quantity, or capacity determined by measuring.
Measurement refers to the comparison of unknown physical quantity with a known quantity.
for eg. measurement of body while sewing clothes.......
