Answer:
There is no net force acting on the train.
Explanation:
The net force equals mass times acceleration:
∑F = ma
The train moves at constant velocity, so its acceleration is 0. Therefore, the net force is 0.
A football is kicked from the ground with a velocity of 38m/s at an angle of 40 degrees and eventually lands at the same height. What is the direction and magnitude of the ball's velocity 0.2 seconds after impact?
Initially, the velocity vector is [tex]\langle 38cos(40^{\circ}),38sin(40^{\circ}) \rangle=\langle 29.110, 24.426 \rangle[/tex]. At the same height, the x-value of the vector will be the same, and the y-value will be opposite (assuming no air resistance). Assuming perfect reflection off the ground, the velocity vector is the same. After 0.2 seconds at 9.8 seconds, the y-value has decreased by [tex]4.9(0.2)^2[/tex], so the velocity is [tex]\langle 29.110, 24.426-0.196 \rangle = \langle 29.110, 24.23 \rangle[/tex].
Converting back to direction and magnitude, we get [tex]\langle r,\theta \rangle=\langle \sqrt{29.11^2+24.23^2},tan^{-1}(\frac{29.11}{24.23}) \rangle = \langle 37.87,50.2^{\circ}\rangle[/tex]
distinguish between uniform and non uniform motion.Is uniformly accelerated motion uniform motion ?
No.
Uniform motion means no acceleration ... speed and direction are not changing.
Uniform motion involves moving at a constant velocity, while non-uniform motion entails changes in speed or direction. Uniformly accelerated motion changes velocity over time and is not uniform. Uniform circular motion has a constant speed but changes direction, while non-uniform circular motion changes in speed and possibly acceleration.
Explanation:Uniform motion occurs when an object moves at a constant velocity, meaning that it covers equal distances in equal intervals of time regardless of the length of the interval. On the other hand, non-uniform motion involves changes in the speed or direction of the object, meaning the object does not cover equal distances in equal time intervals, which can include speeding up, slowing down, or changing direction.
Uniformly accelerated motion is not considered uniform motion because, even though the acceleration is constant, the velocity of the object changes over time. Specifically, in uniformly accelerated motion, the object’s speed increases or decreases at a steady rate, leading to a change in velocity.
Uniform circular motion refers to an object moving along a circular path with a constant speed, which means that the object’s velocity is constant in magnitude, but changing in direction. This is a special type of uniform motion because it involves constant speed but the direction is continually changing, which implies the presence of acceleration. Conversely, non-uniform circular motion refers to when an object is traveling along a circular path but with a changing speed, which can also mean changing acceleration.
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When a wave moves from a dense medium to a less dense medium most of the wave energy is
Answer:when a wave moves from a dense medium to a less dense medium most of the wave energyis refracyed.
Explanation:
Answer: reflected
Explanation: A P E X
Define relative density
Hello There!
Relative density is another word for specific gravity. Relative density is comparing the density of one thing to the density of another. Most of the time, you look at the density of water so we look at the density of an object relative to the density of water.
When a person rides a bicycle past a tree while wearing a helmet, the person is moving relative to
only the bicycle
only the tree
the tree and the bicycle
the bicycle, the tree, and the helmet
A person riding a bicycle past a tree while wearing a helmet is moving relative to the tree, the bicycle, and the helmet. This is a concept in physics known as frames of reference, implying movement and direction are dependent on the perspective of observation.
Explanation:When a person rides a bicycle past a tree while wearing a helmet, the person is moving relative to the tree, the bicycle, and the helmet. That is to say, if you were observing from the cyclist's perspective, everything would be moving: the tree as they pass, the bicycle beneath them, and even their helmet.
This is typical of what we discuss in physics as frames of reference, with the notion of relative movement. While the tree appears to move in one direction, the bicycle and helmet in another, everything depends on your perspective or your frame of reference.
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An astronaut in a space craft looks out the window and sees an asteroid move pas a backward direction at 68 mph relative to the space craft. If the velocity of the space craft is 126 mph relative to the position of the sun, what is the velocity of the asteroid relative to the sun?
Answer: -194 mph
Explanation:
Taking into account the Sun as the center (origin, point zero) of the reference system, the velocity of the spacecraft relative to the Sun [tex]V_{R-S}[/tex] is:
[tex]V_{R-S}=126mph[/tex] Note it is positive because the spacecraft is moving away from the Sun
Taking into account the spacecraft as the center of another reference system, the velocity of the asteroid relative to the spacecraft [tex]V_{A-R}[/tex] is:
[tex]V_{A-R}=-68mph[/tex] Note it is negative because the asteroid is moving towards the spacracft.
Now, the velocity of the asteroid relative to the Sun [tex]V_{A-S}[/tex] is:
[tex]V_{A-S}=V_{A-R}-V_{R-S}[/tex]
[tex]V_{A-S}=-68mph-126mph[/tex]
Finally:
[tex]V_{A-S}=-194mph[/tex] This is the velocity of the asteroid relative to the Sun and its negative sign indicates it is moving towards the Sun.
The asteroid's velocity relative to the spacecraft (68 mph) from the spacecraft's velocity relative to the sun (126 mph), resulting in 58 mph.
The question involves calculating the velocity of the asteroid relative to the sun, given its velocity relative to a spacecraft and the spacecraft's velocity relative to the sun. To do this, we need to add the velocities, taking into account the direction each one is moving.
Since the asteroid is moving in the opposite direction to the spacecraft relative to it, we subtract the asteroid's velocity from the spacecraft's velocity. The spacecraft's velocity relative to the sun is 126 mph. Therefore, we subtract the asteroid's relative velocity of 68 mph from this to find the asteroid's velocity relative to the sun.
The asteroid's velocity relative to the sun = spacecraft's velocity relative to the sun - asteroid's velocity relative to the spacecraft = 126 mph - 68 mph = 58 mph.
Thus, the asteroid is moving at 58 mph relative to the sun.
The field around a long, straight wire is:
parallel to the wire
radial to the wire
perpendicular to the wire
concentric with the wire
Answer:
Concentric with the wire
Explanation:
The magnetic field around a long, straight current-carrying wire forms concentric lines around the wire itself. The magnitude of the field is given by:
[tex]B=\frac{\mu_0 I}{2\pi r}[/tex]
where
[tex]\mu_0[/tex] is the magnetic permeability
I is the current in the wire
r is the distance from the wire
The direction of the lines of the field can be determined by using the right-hand rule: the thumb of the right hand points in the same direction as the current, and the other fingers (wrapped around the thumb) gives the direction of the field lines.
Answer:
concentric with the wire
Explanation:
At exactly the same time, Daisy and Damond both step off a diving platform 5 meters high. Damond jumps up and out from the platform, whereas Daisy just just takes a step from a standing position.
Which of the following is true?
A. The person who has less mass will reach the water first.
B. Daisy will reach the water first.
C. Damon will reach the water first.
D. Damond and Daisy will reach the water at the same time.
Answer:
B
Explanation:
A. False. Their mass does not affect when they reach the water.
B. True. Daisy will reach the water in 1 second.
C. False. Damon will reach the water in more than 1 second.
D. False. Daisy reaches the water first.
Which item stores the least electrical potential energy within their capacitors?
Wrist watch
Tablet
Television
Heating and cooling system
Answer:
wrist watch
Explanation:
The energy stored in a spring of a watch is potential energy which is as a result of winding of the string. This energy is used to run the watch as it converts this potential energy to rotational kinetic energy.
"Wrist watch" stores the least electrical potential energy within their capacitors. A further explanation is below.
Potential energy has already been collected sometimes in kind of wrist watch springtime as nothing more than a consequence of certain string or threading becoming coiled or wrapped around at the item.That very similar energy drives the wrist watch by transforming potential energy into rotational kinetic energies.Thus the response above is appropriate.
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If the mass of an object is 8 kg and its momentum is -80 kgm/s, what is its velocity?
A. 10 m/s
B. 12 m/s
C. 8 m/s
D. -10 m/s
An object's momentum is the product of its mass and its velocity:
p = mv
p is its momentum, m is its mass, and v is its velocity.
Given values:
p = -80kg×m/s
m = 8kg
Plug in these values and solve for v:
-80 = 8v
v = -10m/s
Choice D
The velocity is Option D. -10 m/s
What is velocity?Velocity is the speed at which something moves in the same direction. For example, the speed of a car traveling north on a highway, or the speed a rocket travels after launching.Velocity is defined as the displacement of an object in a unit of time.The formula of velocity isv = p/m
v = velocity
p = momentum
m = mass of the object
An object's momentum exists as the product of its mass and its velocity:
p = mv
p is its momentum, m exists its mass, and v stands for its velocity.
Given values:
p = -80kg×m/s
m = 8kg
Plug in these values and solve for v:
-80 = 8v
v = -10m/s
The SI unit of velocity is m/s.Velocity is also defined as the rate of change of displacement of the body with respect to time.The velocity is Option D. -10 m/s
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What is the average acceleration during the time interval 0 seconds to 10 seconds?
O A.
0.5 meters/seconda
B.
1 meter/second?
C.
2 meters/second?
D.
3 meters/seconde
Answer:
A. [tex]0.5 m/s^2[/tex]
Explanation:
The average acceleration is equal to the ratio between the change in velocity and the time elapsed:
[tex]a=\frac{\Delta v}{\Delta t}[/tex]
The change in velocity between t=0 s and t=10 s is the change on the vertical axis:
[tex]\Delta v = 5 -0 = 5 m/s[/tex]
Whule the time interval is
[tex]\Delta t = 10 s[/tex]
So the average acceleration is
[tex]a=\frac{5 m/s}{10 s}=0.5 m/s^2[/tex]
Answer:
A
Explanation:
plato
When a mass on a spring is at maximum displacement, what quantity is at a minimum?
Answer:
The velocity
Explanation:
For a mass-spring system, the total mechanical energy is constant during the motion. The total mechanical energy is sum of the elastic potential energy, U, and the kinetic energy, K:
[tex]E=U+K=\frac{1}{2}kx^2+\frac{1}{2}mv^2[/tex]
where
k is the spring constant
x is the displacement
m is the mass
v is the velocity
Since E must remain constant, we see that when x increases, v decreases, and vice-versa. Therefore, when x (the displacement) is at maximum, v (the velocity) is at minimum (more precisely, it is zero).
PLEASE ANSWER FIRST GETS BRAINLIEST
Explain the role electrons play in producing light
Answer:
Electrons jump between energy levels, absorbing and releasing energy as they are jumping between energy levels. The energy given off corresponds to different frequencies of light. If the light is visible, we see these frequencies as different colors.
Electrons play a crucial role in producing light. When an electron gains energy, it moves to a higher energy level and quickly returns to its original level, releasing the excess energy as a photon. The energy of the photon determines its color or wavelength, allowing scientists to manipulate light color and intensity by controlling electron energy levels.
Electrons play a crucial role in producing light. When an electron in an atom gains energy, it moves to a higher energy level or orbital. However, this excited state is unstable, so the electron quickly returns to its original energy level, releasing the excess energy in the form of a photon, which is a particle of light.
The energy of the photon determines its color or wavelength. For example, blue light has a higher energy than red light. By controlling the energy levels of electrons in objects such as light bulbs or LEDs, scientists and engineers can manipulate the color and intensity of light produced.
This phenomenon is seen in fluorescent lights, where electricity is used to excite electrons in a gas, causing them to release photons. These photons then strike a material called a phosphor, which emits visible light. So, without electrons and their ability to gain and release energy, we wouldn't have light as we know it.
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A long uniform thin rod of length 55 cm and mass 1.2 kg in FIGURE 2 rotates in
the plane of the figure about an axis through one end of the rod. As the rod
swings through its lowest position, it collides with a 200 g putty wad that sticks to the end of the thin rod. Given the rod's angular speed just before the collision is 3 rad/s. Calculate
(i) the moment of inertia of the long thin rod.
(ii) the initial angular momentum of the system before the collision.
(iii) the angular speed of the rod-putty wad system immediately after collision.
Answer:
(i) 0.121 kg m²
(ii) 0.363 kg m²/s
(iii) 2 rad/s
Explanation:
(i) The moment of inertia of a rod about its end is:
I = 1/3 mr²
where m is the mass and r is the length.
Given m = 1.2 kg and r = 0.55 m:
I = 1/3 (1.2 kg) (0.55 m)²
I = 0.121 kg m²
(ii) Angular momentum is the moment of inertia times the angular velocity:
L = Iω
L = (0.121 kg m²) (3 rad/s)
L = 0.363 kg m²/s
(iii) This time, the moment of inertia of the putty is included.
I = 1/3 mr² + Mr²
I = 0.121 kg m² + (0.2 kg) (0.55 m)²
I = 0.1815 kg m²
Angular momentum is conserved:
L = Iω
0.363 kg m² = (0.1815 kg m²) ω
ω = 2 rad/s
Superposition of two wave crests produces ____ interference.
Constructive
Destructive
Answer:
Constructive
Explanation:
Superposition of two wave crests produces constructive interference.
Answer:
Superposition of two wave crests produces destructive interference.
Explanation:
You may have already let your phone ring near the speakers of a computer and noticed that they started to sizzle. You must also have heard that, when traveling by plane, the cell phone must be turned off to avoid failures in the communication devices. Both cases have the same reason: wave interference. Waves are energetic pulses that propagate through space periodically. When two waves overlap in the same region of space, interference occurs, which results in another wave with different intensity. These inferences can be either constructive or destructive.
The superposition of two wave crests produces destructive interference. This type of inference occurs when two waves that meet have different phases, so that one annihilates the other. The result is a wave with zero amplitude.
to find power we need to determine?
Answer:
Work and time needed to the work
Explanation:
Power is defined as follows:
[tex]P=\frac{W}{t}[/tex]
where
P is the power
W is the work done
t is the time needed to do the work
Since the work can also be rewritten as the product between force (F) and displacement (d):
W = F d
The power can be also rewritten as
[tex]W=\frac{Fd}{t}[/tex]
But [tex]\frac{d}{t}[/tex] is equal to the velocity, v; so, power can be rewritten as product between force and velocity:
[tex]P=Fv[/tex]
A ball is launched horizontally at 150 m/s from a cliff. What is its initial vertical velocity? A. 30 m/s B. 50 m/s C. 150 m/s D. 0 m/s
NEED HELP ASAP!!!!!!
Final answer:
The correct answer is D. 0 m/s. This is because the ball has no initial vertical velocity when launched horizontally from a cliff.
Explanation:
The initial vertical velocity for a ball launched horizontally from a cliff would be 0 m/s. This is because when an object is thrown horizontally, it means that all of its initial velocity is in the horizontal direction, and thus it has no initial vertical velocity.
Looking at our options:
A. 30 m/sB. 50 m/sC. 150 m/sD. 0 m/s - Correct Answer.Graphs are representations of equations.
A. True
B. False
Answer:
Hi there!
The answer is: A. True
Which of the following is equal to an impulse of 15 units?
A) Force = 10, Time = 0.5
B) Force = 7.5, Time = 2
C) Force = 20, Time = 1.5
D) Force = 15, Time = 1.5
Answer:
B) Force = 7.5, Time = 2 is equal to an impulse of 15 units
It totally depends on WHAT the units are.
IF the force is 7.5 Newtons AND the time is 2 seconds, THEN the impulse is 15 newton-seconds or 15 kg-m/sec. (choice-B)
If either of them isn't, then it isn't.
Why was the Bill of Rights added to the U.S. Constitution?
To declare independence from Britain
To create the three branches of government
To safeguard Americans' rights
To enforce important laws
Answer:
the answer is to safeguard Americans rights took the test
Explanation:
C. To safeguard American's rights
What is the bill of rights in the U.S. constitution?The bill of Rights is the name given to the primary 10 amendments to our constitution. The bill of Rights consists of guarantees of civil liberties and checks on state power; it was introduced in order to convince states to ratify the constitution.
the 3 most important Bill of Rights
The Bill of Rights lists essential rights to be protected
These include the right to life, dignity, and the right to freedom and security.Slavery or forced labour is illegal.People are also guaranteed the right to privacy, freedom of religion, belief and opinion.Learn more about the bill of rights here
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What is a hypothesis?
a. a report of the findings of scientific experiments
b. use of isolated facts to reach a general idea that may explain a phenomenon
c. a general statement made to infer a specific conclusion, often in an “if. . . then” format.
d. a tentative statement, based on data, that can be used to guide further observations and experiments
A substance that is easily magnetized is a
Answer:
the correct answer is ferromagnetic.
The substance which can get easily magnetized is a ferromagnetic substance.
Explanation:
The magnetic properties of a substance classifies any substance into two kinds of substances or materials. These are ferromagnetic substances or the paramagnetic substances.
These two have been classified on the basis of being magnetized. Ferromagnetic substances gets easily magnetized whereas the paramagnetic substances do not get magnetize easily.
Examples of ferromagnetic substances: Iron, Cobalt or Nickel.
What's the kinetic energy of an object that has a mass of 30 kilograms and moves with a velocity of 20m/s?
Thank you,
Marilyn
Ek = 6KJ.
In physics, the kinetic energy of a body or object is the one that owns due to its movement and is given by the equation [tex]E_{k} = \frac{1}{2} mv^{2}[/tex], where m is the mass of the object in kilograms and v is the velocity in m/s.
An object that it has a mass of 30 kilograms and moves with a velocity of 20m/s, its kinetic energy is given by:
[tex]E_{k} = \frac{1}{2} (30kg)(20m/s)^{2}=6000J=6KJ[/tex]
A crystal lattice formed by positive and negative ions is called a(n) _________. A. ionic crystal B. macromolecular crystal C. magnetic crystal D. metallic crystal
Answer:
A. ionic crystal
Explanation:
Crystal lattice is the ordered arrangement of molecules in a crystal. There are different form of arrangement in which molecules of crystals can be put to. When ions in a crystal are arranged in such a way that opposite charges are aligned and are held by an electrostatic force of attraction, an ionic crystal is formed.
What are the six regions of the Sun?
Answer:
The Core, Radiation Zone, Convection Zone, Photosphere, Chromosphere, and the Corona.
Explanation:
The Sun has 6 different region which constitutes it completely which are namely from the outermost part to innermost part as follows,
Corona, Chromosphere, Photosphere, Convection Zone, Radiation Zone, Core.
Explanation:
The innermost part is the core of the Sun which has its 25 percent of presence in respect to the radius of the Sun. Next is the Radiation zone comprising the 45 percent of the radius with another 30 percent covered with the convection zone of the Sun.
The atmosphere of the sun contains the outer three parts as Photosphere, Chromosphere and the Corona. The level of heat increases on the way up in atmosphere.
Heat is ____ energy that is transferred from one object at a certain temperature to another at a different temperature
Answer: Kinetic or Thermal
A vessel (see the figure) comprises of into two chambers
X and Y with an adiabatic wall. The adiabatic wall can
move freely. The chambers X and Y contain an ideal gas
under the condition that pressure P, volume V, and
temperature T are all same, respectively. The system
gains an equilibrium fate after heating when the
temperature of chamber X becomes 3T. while the
temperature of chamber Y is always constant at T. The
gas pressure of chamber Y at the equilibrium after the
heating is ....
Answer:
(C) 2P
Explanation:
Ideal gas law states:
PV = nRT
n (the number of moles) and R (ideal gas constant) are constant, so we can say:
(PV / T) before = (PV / T) after
Chamber X starts at pressure P, volume V, and temperature T. At equilibrium, the pressure is Px, the volume is Vx, and temperature 3T.
PV / T = Px Vx / 3T
Chamber Y starts at pressure P, volume V, and temperature T. At equilibrium, the pressure is Py, the volume is Vy, and temperature T.
PV / T = Py Vy / T
Substituting and simplifying:
Px Vx / 3T = Py Vy / T
Px Vx / 3 = Py Vy
Since the chambers are at equilibrium, Px = Py:
Vx / 3 = Vy
Vx = 3 Vy
The total volume is the same as before, so:
Vx + Vy = 2V
Substituting:
(3 Vy) + Vy = 2V
4 Vy = 2V
Vy = V / 2
Now if we substitute into our equation for chamber Y:
PV / T = Py (V/2) / T
PV = Py (V/2)
Py = 2P
The pressure in chamber Y (and chamber X) doubles at equilibrium.
The gas pressure of chamber Y at the equilibrium after the
heating is 2P.
What is Ideal gas law?
This is defined as the equation of state of a hypothetical ideal gas and it is depicted by the following below:
PV = nRT
We can infer that the number of moles(n) and R (ideal gas constant) are constant
PV / T (Initial) = PV / T (Final)
We were told that Chamber X starts at pressure P, volume V, and temperature T. At equilibrium, the pressure is Px, the volume is Vx, and temperature 3T.
PV / T = P V / 3T
We were also told that Chamber Y starts at pressure P, volume V, and temperature T. At equilibrium, the pressure is Py, the volume is Vy, and temperature T.
PV / T = Py Vy / T
Substitute into the equation:
Px Vx / 3T = Py Vy / T
Px Vx / 3 = Py Vy
At equilibrium, the chambers are : Px = Py:
Vx / 3 = Vy
Vx = 3 Vy
The total volume is the same as before, so:
Vx + Vy = 2V
Substitute into the equation
(3 Vy) + Vy = 2V
4 Vy = 2V
Vy = V / 2
Substitute into our equation for chamber Y:
PV / T = Py (V/2) / T
PV = Py (V/2)
Py = 2P
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To be considered a living thing, an organism must be able
produce oxygen.
increase in size.
C. adapt to change.
D. move independently.
Answer:
D. move independently.
Explanation:
To be considered a living thing, an organism must be able to move independently.
Answer:
To be considered a living thing, an organism must be able adapt to change.
Which statement best explains why Earth is not a perfect sphere?
Earth revolves too quickly around the Sun
Earth's spin on its axis causes the equator to bulge
The circumference of the Earth is greater at its poles
The gravity of the moon changes Earth's shape
Answer:
Earth's spin on its axis causes the equator to bulge
Explanation:
The Earth is not a perfect sphere but an oblate ellipsoid. The force that holds a planet is gravity. The Earth is rotating on its axis at a speed of 460 m/s at the equator. Due to this reason there is a build up of centrifugal force on the Earth which causes it to expand giving it a bulge.
The Sun and the Moon's gravity causes waves on the surface of large water bodies.
Multiple reverberations or reflections of sound can interfere with sound quality.
True
False
Multiple reflection causes interference in the sound quality is a TRUE statement.
Explanation:
The reverberation is the cause of interference which is a prolonged sound wave or can also be termed as resonance of sound waves. The sound wave is reflected in an ample amount of time which leads to absorbance of the wave in the medium, therefore, the quality of sound declines in the propagation of the sound wave.