If no braking occurs, a total of how much power would be required to keep the railcar moving at 40 m/s
Answer:
40 kW
Explanation:
A railcar has a continuous 1000 N decelerating force any time it is in motion. If no braking occurs, how much power would be required to keep the railcar moving at 40 m/s
Solution:
Power in Physics is the rate of doing work and the work can be mechanical, electrical, etc. The S.I unit of power is the watts (W).
The power required to keep the car moving must match the work done by the friction force (decelerating force) that tends to slow down the railcar.
Work done = Force * displacement
Power = Work done / time = (Force * displacement) / time
Power = Force * (displacement / time)
Power = force * velocity = 1000 N * 40 m/s = 40000 W
Power = 40 kW
A gas at a pressure p is compressed to half it original volume and twice its original temperature. The new pressure is
Answer:
4p
Explanation:
If you halve the volume the pressure will double as they are inversely proportional. If you double the temperature the particles have double the kinetic energy so the pressure will double again.
So:
p×2×2 = 4p
Answer:
P V = n R T
P2 V2 / (P1 V1) = T2 / T1
P2 = (T2 / T1) (V1 / V2) P1 = 2 * 2 = 4
If the Big Bang theory is correct, then the universe is billions of years old. And if the Big Bang theory is correct, then the universe was not created in six days. Thus, if the universe is billions of years old, then it was not created in six days. Group of answer choices No answer text provided. Deductive Inductive No answer text provided.
Answer:
Deductive
Explanation:
Deductive reasoning or logic is the form of logic where the reasoning process from which the conclusion is reached is based on one or more premises. Deductive logic, is a top down logic, where premises are linked with conclusion, such that true premises give a true conclusion which is reached by a process of narrowing the focus based on certainty
The question bases the conclusion on the premise that the Big Bang theory which is based on scientific evidence is several billions of years old and if the theory is correct the universe (as it is today) was not created six days
orange light has a wavelength of 600nm. calculate the frequency if the speed of light in vacuum
the correct answer is ---- 122
If a car drives 10 mph South, this is an example of a:
A. Displacement
B. Velocity
C. Distance
D. Speed
If a car drives 10 mph South, this is an example of a:
If a car drives 10 mph South, this is an example of a: Displacement
[DISPLACEMENT IS THE SHORT DISTANCE TRAVELLED BY A BODY AT A CERTAIN DIRECTION]
A velocity would be an automobile traveling south at 10 mph. Option B is correct.
What is velocity?The change of displacement with respect to time is defined as velocity. velocity is a vector quantity. It is a time-based component. Its unit is m/sec.
If the direction is given quantity is a vector quantity. In the given data the direction is given, that's why a car drives 10 mph South, this is an example of a velocity.
Hence, option B is correct.
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If you are driving 90 km/hkm/h along a straight road and you look to the side for 2.8 ss , how far do you travel during this inattentive period
Answer:
Distance = 70 meters
Explanation:
Given the following data;
Speed = 90 km/h
Time = 2.8 seconds
Conversion:
90 km/h to meters per seconds = 90 * 1000/3600 = 90000/3600 = 25 m/s
To find the distance covered during this inattentive period;
Speed can be defined as distance covered per unit time. Speed is a scalar quantity and as such it has magnitude but no direction.
Mathematically, speed is given by the formula;
[tex]Speed = \frac{distance}{time}[/tex]
Making distance the subject of formula, we have;
[tex] Distance = speed * time [/tex]
Substituting into the above formula, we have;
[tex] Distance = 25 * 2.8 [/tex]
Distance = 70 meters
The boiling point of a substance is _72 degree Celsius. This temperature will be equivalent to Kelvin scale is-------.
Answer:
345 K
Explanation:
Temperature can be defined as a measure of the degree of coldness or hotness of a physical object.
Generally, it is measured with a thermometer and its units are Celsius (°C), Kelvin (K) and Fahrenheit (°F).
Given the following data;
Boiling point = 72°CTo convert the temperature in degree Celsius to Kelvin, we would use the following mathematical expression;
Kelvin = 273 + °C
Substituting into the formula, we have;
Kelvin = 273 + 72
Kelvin = 345 K
Therefore, the temperature of 72°C will be equivalent to 345 K on the Kelvin scale.
What must be the reaction force when someone hits a tree with an axe?
Answer: The correct option is that the axe handle applying a force to the person's hand.
Explanation:
This reaction force is due to Newton's third law of motion. This law states that for every action there is equal and opposite reaction to it. This implies that when a force is being exerted on a surface, the surface must exert a force that is equal and opposite in direction to the exerting force. This law represents a certain symmetry in nature that forces always occur in pairs, and one body cannot exert a force on another without experiencing a force itself.
A typical example of Newton's third law includes:
--> When you hit a tree with an axe: with your hand you exert a force on the tree with the intention to cut it down(action force). The same force you excreted on the tree would be felt in your hands (reaction force).
--> when air rushes out of a balloon: when air escapes for a balloon, the opposite reaction is that the balloon flies up.
Calculate surface tension of an enlarged radius of 4cm to 6cm and amount of work necessary for enlargement was 1.5×10^-4 joules
Answer:
[tex]T=7.5*10^{-5}[/tex]
Explanation:
From the question we are told that:
Radius [tex]r=2cm[/tex]
Work done [tex]W=1.5×10^-4 joules[/tex]
Generally the equation for Work done is mathematically given by
[tex]W=T.dA[/tex]
Therefore
[tex]T=\frac{W}{dr}[/tex]
[tex]T=\frac{1.5*10^{-4}}{2}[/tex]
[tex]T=7.5*10^{-5}[/tex]
A student walks 350 m [S], then 400 m [E20°N], and finally 550 m [N10°W]. Using the component method, find the resultant (total) displacement). Round your answer to the appropriate significant figures. Round your angle to the nearest degree.
In component form, the displacement vectors become
• 350 m [S] ==> (0, -350) m
• 400 m [E 20° N] ==> (400 cos(20°), 400 sin(20°)) m
(which I interpret to mean 20° north of east]
• 550 m [N 10° W] ==> (550 cos(100°), 550 sin(100°)) m
Then the student's total displacement is the sum of these:
(0 + 400 cos(20°) + 550 cos(100°), -350 + 400 sin(20°) + 550 sin(100°)) m
≈ (280.371, 328.452) m
which leaves the student a distance of about 431.8 m from their starting point in a direction of around arctan(328.452/280.371) ≈ 50° from the horizontal, i.e. approximately 431.8 m [E 50° N].
A 4 LBfweight is attached to a spring suspended from the ceiling. When the weight comes to rest at equilibrium, the spring has been stretched 3 inches. The damping constant for the system is 2 LBf−sec ft . If the weight is raised 9 inches above equilibrium and given an initial upward velocity of 2 ft/sec, determine the equation of motion of the weight and give its damping factor, quasiperiod and quasifrequency.
Answer:
attached below
Explanation:
The initial conditions :
x(0) = - 9 inches = -3/4 ft
x'(0) = - 2 ft/sec
spring stretched 3 inches = 1/4 ft
mass = w / g = 4 Ib / 32 ft/sec^2 = 1/8 slug
the spring constant ( k ) = w / l = 4 / ( 1/4 ) = 16 Ib/ft
applying the second law of motion
m d^2x/dt^2 + b dx/dt + kx
= 1/8 d^2x/dt^2 + 2 dx/dt + 16 x
= d^2x/dt^2 + 16 dx/dt + 128 x ------- ( 1 )
we will resolve the above equation to obtain the required equation of motion x( t )
Attached below is the remaining part of the solution
A ball is at the top of the hill. As the ball rolls down the hill, its total mechanical energy will:
Answer:
To explain what happens with the ball we must remember the Law of Conservation of Energy.
This law states that the energy can be neither created nor destroyed only converted from one form of energy to another.
Then,
At the top of the hill, the potential energy is maximum and the kinetic energy equals to zero.
When the ball starts to roll down the potential energy will be lower and the kinetic energy will have a low value.
At the middle of the hill, both energies have the same values.
At the end of the hill, the potential energy will be equal to zero and the kinetic energy will be maximum.
Correct me if I'm wrong...
hope it helps...
Answer this physics question ASAP. please
Answer:
Explanation:
After much working on this, I got the force between A and C to be 12 and the force between B and C to be 9. the total force I found then was 15 N at 53 degrees. I used the angle between A and C as 90 degrees and the angle between B and C to be 0 )I just rotated the right triangle a bit to make it easier to work with).
How are molecules composed of atoms held together?
through gravity
through friction
through chemical bonding
through hydrogen bonding
Answer:
Chemical Bonding
Explanation:
convert the following quantities
[tex]25m {}^{2} \: into \: cm {}^{2} [/tex]
Answer:
[tex] \rm 250000 \; cm^2 [/tex]
Explanation:
Refer to the attachment.
Calculate the percent error of the distanc
A space shuttle was launched from the Earth to the
moon. The average, or accepted, value of the distance
of the Earth to the moon is 238,857 miles, but the
shuttle crew recorded that their trip took 226,316 miles
5.25%
07.15%
3.75%
4.45%
Answer:
5.25%
Explanation:
From the question given above, the following data were obtained:
Accepted value = 238857 miles
Measured value = 226316 miles
Percentage error =.?
Next, we shall determine the absolute error. This can be obtained as follow:
Accepted value = 238857 miles
Measured value = 226316 miles
Absolute Error =?
Absolute Error = |Measured – Accepted|
Absolute Error = |226316 – 238857|
Absolute Error = 12541
Finally, we shall determine the percentage error. This can be obtained as follow:
Accepted value = 238857 miles
Absolute Error = 12541
Percentage error =.?
Percentage error = absolute error / accepted value × 100
Percentage error
= 12541 / 238857 × 100
= 1254100 / 238857
= 5.25%
Therefore, the percentage error is 5.25%.
Which wave interaction results in a change in the direction of the wave as it passes through one medium to another medium?
Answer:
Refraction of waves involves a change in the direction of waves as they pass from one medium to another. Refraction, or the bending of the path of the waves, is accompanied by a change in speed and wavelength of the waves.
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26. D. crushing the sugar cube and dissolving it in water.
27. A. atom
28. B. molecule
29. B. plum pudding model of Joseph John Thomson
30. B. He used cathode ray tubes which showed that all atoms contain tiny negatively charged subatomic particles or electrons.
31. D. protons and neutrons are relatively heavier than electrons.
how long will it take a car to go from 0 to 45 km/hr if they are accelerating at 5 km/hr/s?
Answer:
9 seconds
Explanation:
[tex]acceleration = \frac{final \: speed - initial \: speed}{time \: taken} [/tex]
[tex]5km/ hr/ s = \frac{45 - 0 (km/ h)}{t} [/tex]
cross multiplying
[tex]5t = 45 secs \\ t = 9 \: secs[/tex]
it will take 9secs for the car to go from 0 to 45 km/ h
Which of the following is a primary source?
The answer is C :), I think.
A scientific paper is the primary source. A primary source is an item, document, recording, or any other source. Option C is correct.
What is a scientific paper ?Scientific papers are a specific sort of written work with certain characteristics: they are often published in a periodical called a journal, whose sole objective is to publish this type of work.
A primary source is an item, document, recording, or any other source of information created during the period being studied in the academic area of history.
A scientific paper is the primary source.
Hence,option C is correct.
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Connected to a battery that offers a d.d.p. of 3.0Volts, we have the four lamps, all identical with resistances equal to 2.0 Ohms. The association appears in the figure. Note that the switch is open, so it doesn't pass current in the circuit (it's like an off switch). When the key closes, the lamps come on. Determining the Req of the association and the total current flowing through the circuit, we will find:
Answer:
Option D. 5Ω e 0.6 A
Explanation:
1. Determination of the equivalent resistance.
We'll begin by calculating the equivalent resistance of resistor B and resistor C. This can be obtained as follow:
Resistor B (R₆) = 2 Ω
Resistor C (R꜀) = 2 Ω
Equivalent Resistance (R₆꜀) =?
R₆꜀ = R₆ × R꜀ / R₆ + R꜀ (parallel connection)
R₆꜀ = 2 × 2 / 2 + 2
R₆꜀ = 4 / 4
R₆꜀ = 1 Ω
Finally, we shall determine the equivalent resistance of the circuit. This can be obtained as follow:
Resistor A (Rₐ) = 2 Ω
Equivalent resistance of resistor B and C (R₆꜀) = 1 Ω
Resistor D (Rₔ) = 2 Ω
Equivalent Resistance (R) =?
R = Rₐ + R₆꜀ + Rₔ (series connection)
R = 2 + 1 + 2
R = 5 Ω
Thus, the equivalent resistance of the circuit is 5 Ω
2. Determination of the total current in the circuit.
Potential difference (V) = 3 V
Equivalent resistance (R) = 5 Ω
Total current (I) =?
V = IR
3 = I × 5
Divide both side by 5
I = 3 / 5
I = 0.6 A
Thus, the total current in the circuit is 0.6 A
Summary:
Equivalent resistance = 5 Ω
Current = 0.6 A
Option D gives the current answer to the question.
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.
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.
a body is moving along a circular path 'r'. what will be the distance and displacement of the body when it completed half a revolution?
After half of a revolution ...
==> Distance = π•r
==> Displacement = 2•r
1. A plane flying a triangular patter flies 150 km[N], then 400 km(E). What is the total displacement of the
plane after these two legs? {4}
2. Ken and Susie are standing together. Ken walks 10 m (N) and then 15 m [W]. Susie walks 25 m [E] and
then 30 m [S]. What is the displacement from Ken to Susie? {5}
3. Students are performing an experiment for their physics class and are testing their predictions for
projectile motion. They set up a system so that a beanbag is launched horizontally off one of their
desks with an initial speed of 4.2 m/s. They measure the height of the desk to be 1.3 m.
a. What is the time of flight for the beanbag? {3}
b. What is the range for the beanbag? {2}
4. A historical society is testing an old cannon on the top of an old fort that has rusted and can only be
fired horizontally. They perform a few test fires of the cannon and measure the time of flight to be
3.78 s. How high is the hill? {3}
Answer:
1. The displacement is 427.2 km.
Explanation:
1. A = 150 km North
B = 400 km East
The net displacement is given by
[tex]R =\sqrt{400^2 + 150^2 }\\\\R = 427.2 km[/tex]
what is gama rays an it's uses
Answer:
GAMMA RAYS:
A photon emitted spontaneously by a radioactive substance also : a photon of higher energy than that of an X-ray.
USES OF GAMMA RAYS:
Gamma rays are used in medicine (radiotherapy), industry (sterilization and disinfection), and the nuclear industry. Shielding against gamma rays is essential because they can cause diseases to skin or blood, eye disorders, and cancers.
The weight of a body is 600 N. What is the mass of the body on the surface of the earth?
Explanation:
soln,
weight=600N
mass=?
gravity=9.8 m/s²
now,
mass=weight/gravitymass=600/9.8mass=61.22kghope it helps.
stay safe healthy and happy.Answer:
m = 61.22 kg
Explanation:
F = 600 N
g = 9.8 m/s²
m = ?
F = mg
600 = m(9.8)
---> m = 61.22 kg
A heavier person will have a lower blood level due to a greater amount of ___ in their
Answer:
Blood alcohol content (BAC) is a measure of the amount of alcohol that is present in the blood.
A heavier person will have a lower blood alcohol level due to a greater amount of water in their body. The more a person weighs, the more water he/she tends to have in his/her body. The water has a diluting effect on the alcohol so the BAC will be lower in comparison with a person who is slimmer and has less water in the body.
Explanation:
An athlete runs around a circular track of radius 50 m and finishes at the same point where he began his journey. His total displacement in metre(s) is evaluated to be
Answer:
Explanation:
His displacement is 0 because he ended up exactly where he started.
What type of material does not transfer heat well?