Answer:
work done by friction = 5889 J
Explanation:
We are given;
Mass of car; m = 130 kg
Speed at point A; v1 = 25 m/s
Speed at point B: v2 = 8 m/s
Since radius is 12 m
At point A, distance is; y1 = 12 m
At point B, distance is; y2 = -12 m
Now, formula for work done by all the forces is given by the equation;
Total work;
W_gravity + W_others = K2 - K1
Where W_others is work done by other forces which is equal to work done by friction
Where K2 - K1 is change in kinetic energy.
W_grav is also change in potential energy and is expressed as;
W_grav = mgy1 - mgy2
K2 - K1 = ½m(v1)² - ½m(v2)²
Thus;
mgy1 - mgy2 + W_others = ½m(v1)² - ½m(v2)²
Making W_others the subject;
W_others = ½m(v1)² - ½m(v2)² + mgy2 - mgy1
Plugging in the relevant values;
W_others = (½ × 130 × 25²) - (½ × 130 × 8²) + (130 × 9.8 × -12) - (130 × 9.8 × 12)
W_others = 5889 J
Recall that I earlier said W_others = work done by friction.
Thus, work done by friction = 5889 J
A wheel rotates about a fixed axis with an initial angular velocity of 24 rad/s. During a 4 s interval the angular velocity decreases to 14 rad/s. Assume that the angular acceleration is constant during the 4 s interval. How many radians does the wheel turn through during the 4 s interval
Answer:
[tex]\theta=76\ rad[/tex]
Explanation:
Hoven that,
Initial angular velocity of the wheel = 24 rad/s
Final angular velocity = 14 m/s
Time, t = 4 s
We need to find how many radians does the wheel turn through during the 4 s interval. Let the displacement is [tex]\theta[/tex]. Using second equation of rotational kinematics to find it such that,
[tex]\theta=\omega_i t+\dfrac{1}{2}\alpha t^2[/tex]
Where
[tex]\alpha[/tex] is angular acceleration
[tex]\alpha =\dfrac{\omega_f-\omega_i}{t}\\\\\alpha =\dfrac{14-24}{4}\\\\\alpha =-2.5\ rad/s^2[/tex]
So,
[tex]\theta=24\times 4+\dfrac{1}{2}\times (-2.5)\times 4^2\\\\\theta=76\ rad[/tex]
So, it will turn 76 radian during the 4 s interval.
The kinetic energy and the potential energy of the cannonball is constantly ________ as it travels through the air.
A. Changing
B. Increasing
C. Constant
D. Decreasing
Answer:
C. Constant
Explanation:
The total energy of the cannonball remains constant as it travels through the air.
Answer:
Explanation:
hi my name is Ava
Chris used a non plane mirror to check out an box resting on a shelf. He wanted to find
the focal length of the mirror. The image of the box was located 15 cm behind the mirror
and the box was placed 19 cm from the mirror.
Chris used a non-plane mirror to check out a box resting on a shelf, the focal length of the mirror is mathematically given as
f=8.38cm
What is the focal length of the mirror?Question Parameter(s):
The image of the box was located 15 cm behind the mirror
and the box was placed 19 cm from the mirror.
Generally, the equation for the focal length is mathematically given as
1/f=1/u+1/v
Therefore
1/f=1/15+1/19
f=8.3823529cm
In conclusion, the focal length of the mirror
f=8.3823529cm
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Scientists have concluded that the uppermost part of the mantle is partially-molten. Which observation helped them reach this conclusion?
Answer:
P and S waves slow down when they reach this layer. The asthenosphere, also known as the magma chamber, is the uppermost component of the mantle. This layer is partially molten and is a ductile zone in a tectonically poor state.
It's almost hard and seismic waves move through the asthenosphere at a slow rate. The fragile lithosphere and the uppermost portion of the asthenosphere are assumed to be rigid.
seismic waves travel more quickly through denser materials and therefore generally travel more quickly with the depth it moves more slowly through a liquid than a solid. Molten areas within the Earth slow down P waves and stop S waves because their shearing motion cannot be transmitted through a liquid. Partially molten areas may slow down the P waves and attenuate or weaken S waves.
hope this helps...
S and P wave slow down and stop in the uppermost part of the mantle. - For this, scientists have concluded that the uppermost part of the mantle is partially-molten.
What is mantle?A planetary body's mantle is a layer that is surrounded by the crust on top and the core underneath. The largest and most substantial layer of a planetary body, mantles are often comprised of rock or ice. Planetary bodies that have undergone density differentiation typically have mantles. Mantles are found on all terrestrial planets (including Earth), many asteroids, and a few planetary moons.
Between the crust and the outer core, there is a silicate rock layer known as the Earth's mantle. Despite being mostly solid, it behaves like a viscous fluid over geological time. Oceanic crust is created by the partial melting of the mantle at mid-ocean ridges, and continental crust is created by the partial melting of the mantle at subduction zones.
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A mass of 3 kg stretches a spring 9m. The mass is acted on by an external force of 2 AND. The Mass moves in a medium that imparts a viscous force of 1 N when the speed of the mass is 4m/sec The mass is pulled down 8 cm below its equilibrium position, and then set in motion inthe upward direction with a velocity of 5 m/sec. State the initial value problem describing the motion of the mass. DO NOT SOLVE.
Answer:
k y -b [tex]\frac{dy}{dt}[/tex]dy / dt = m [tex]\frac{d^2y}{dt^2}[/tex]
give us some initial conditions
1) friction force fr = 1N when v = 4m / s
2) an initial displacement of x = 0.08 m for t=0 s
Explanation:
In this exercise, you are asked to state the problem you are posing. We are going to find the equation of motion for this exercise. Let's start with Newton's second law
Let's set a reference system with the y-axis in a vertical and positive direction upwards.
We have four forces: an external downward force, negative in sign, the but that goes down and is negative, the Hook force that goes up and is positive and the friction force that opposes the movement, in this case it goes down being negative
let's write Newton's second law
F_e -F -fr - W = m a
where
F_e = -kDy = - k y
fr = - b v = -b dy / dt
W = mg
we substitute for the specific case, that is, using the signs
k y -b [tex]\frac{dy}{dt}[/tex] - m g - F = m [tex]\frac{d^2y}{dt^2}[/tex]
In the initial condition of the problem, before starting the movement, the friction force is zero and the acceleration is also zero
k y - m g - F = 0
from this equation you can find the spring constant, y= 9m and F=2 N
It is not clear if when the movement starts this external force becomes zero, but since it balances the weight we can eliminate the two forces that have the same magnitude and opposite direction, so the equation remains
k y - b [tex]\frac{dy}{dt}[/tex]dy / dt = m [tex]\frac{d^2y}{dt^2}[/tex]
give us some initial conditions
1) friction force fr = 1N when v = 4m / s
2) an initial displacement of x = 0.08 m for t=0 s
therefore, to initiate the movement, a small external force F 'is applied that moves the system to a new equilibrium position and this small force F' is made zero, thus initiating an oscillatory movement, described by the equation.
k y -b [tex]\frac{dy}{dt}[/tex]dy / dt = m [tex]\frac{d^2y}{dt^2}[/tex]
This is a differential equation of the second degree, therefore it needs two initial conditions for its complete solution
The initial amount of displacement corresponds to the amplitude of movement A = 0.08 m
Your eyes form upside-down images, which are then flipped right-side-up by our brains.
True
False
Answer:
I believe it is true, but our brains don’t do it, I think it is the lenses in our eyes that do it. I might be wrong tho
Explanation:
Answer:
Yes it is true that our eyes form upside-down images, which are flipped right-side-up by our brain.
Temperature is the measure of the average kinetic energy of the particles in an object. True False
Answer:
true
Explanation:
with increased temperature particles move faster as they gain kinetic energy
Which of Earth’s spheres is composed of a mixture of gases?
Answer:
Earth's atmosphere is a layer of gases surrounding the planet Earth and retained by the Earth's gravity. It contains roughly 78% nitrogen and 21% oxygen 0.97% argon and carbon dioxide 0.04% trace amounts of other gases, and water vapor. This mixture of gases is commonly known as air. Explanation:
Answer:
the earth's atmosphere
Explanation:
hope that helps
A water balloon weighing 4.5 N rests on a table. The balloon has an area of 2.6 x 10-3
m² in contact with the table. What pressure does the balloon exert on the table?
Answer:
the pressure the balloon exerts on the table is 1,730.77 N/m²
Explanation:
Given;
weight of the water balloon, F = 4.5 N
area of the balloon, A = 2.6 x 10⁻³ m²
The pressure the balloon exerts on the table is calculated as follows;
[tex]P = \frac{F}{A}[/tex]
substitute the given values and solve for pressure, P;
[tex]P = \frac{4.5}{2.6 \times 10^{-3}} \\\\P = 1,730.77 \ N/m^2[/tex]
Therefore, the pressure the balloon exerts on the table is 1,730.77 N/m²
Acep
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White light is incident normally on a thin soap film (n = 1.33) suspended in air:
(a) What are the two minimum thickness that will destructively
reflect yellow light
of wavelength 590 nm?
I hope this will help you. Here is the link http://web.physics.ucsb.edu/~phys6c/summer2006/hw4solutions
If you live in Melbourne, Australia, the local magnetic field has a strength of about 4x10-5 T. The magnetic field vector is directed northward, making an angle of 30 deg above the horizontal. An electron in Melbourne is moving parallel to the ground, in the west direction, at a speed of 9x105 m/s. What are the magnitude and direction of the magnetic force on the electron
Answer:
[tex]5.76\times 10^{-18}\ \text{N}[/tex] perpendicular to the velocity and magnetic field
Explanation:
B = Magnetic field = [tex]4\times 10^{-5}\ \text{T}[/tex]
[tex]\theta[/tex] = Angle the magnetic field makes with the horizontal = [tex]30^{\circ}[/tex]
v = Velocity of electron = [tex]9\times 10^5\ \text{m/s}[/tex]
q = Charge of electron = [tex]1.6\times 10^{-19}\ \text{C}[/tex]
Magnetic force is given by
[tex]F=qvB\sin\theta\\\Rightarrow F=1.6\times 10^{-19}\times 9\times 10^5\times 4\times 10^{-5}\sin30^{\circ}\\\Rightarrow F=2.88\times 10^{-18}\ \text{N}[/tex]
The magnitude of the magnetic force is [tex]2.88\times 10^{-18}\ \text{N}[/tex] and the direction is perpendicular to the velocity and magnetic field.
Water can form large dewdrops in nature how would droplets made of isopropyl alcohol instead of water be different
Answer:
isopropyl alcohol would form smaller droplets, because it has lower surface tension than water has
Explanation:
Ap3x
The droplets made of isopropyl alcohol instead of water be smaller due to surface tension.
What is droplets?The single drop of a liquid in the form of sphere is called droplet.
Water can form large dewdrops in nature. Isopropyl alcohol would form smaller droplets, because it has lower surface tension than water.
Surface tension is the property of the liquid to acquire minimum surface area.
Thus, droplets made of isopropyl alcohol instead of water be smaller.
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Rasheeda made a model of a plant cell and labeled parts of the cell that are not found in animal cells. Which other part of the cell should Rasheeda label?
A) cytoplasm
B) large central vacuole
C) lysosomes
D) mitochondria
Answer:
Cytoplasm
Explanation:
At noon, ship A is 110 km west of ship B. Ship A is sailing east at 20 km/h and ship B is sailing north at 15 km/h. How fast is the distance between the ships changing at 4:00 PM
Answer:
[tex]4.47\ \text{km/h}[/tex]
Explanation:
[tex]\dfrac{da}{dt}[/tex] = Rate at which the distance between A and starting point of B is changing = -20 km/h
[tex]\dfrac{db}{dt}[/tex] = Rate at which the distance of B is changing = 15 km/h
[tex]\dfrac{dc}{dt}[/tex] = Rate at which the distance between A and B is changing
Time after which the rate at which the distance between A and B is changing is 4 hours
Distance covered by A in 4 hours = [tex]20\times 4=80\ \text{km}[/tex]
a = Distance remaining to the start point of B = [tex]110-80=30\ \text{km}[/tex]
b = Distance covered by B in 4 hours = [tex]15\times 4=60\ \text{km}[/tex]
Distance between A and B after 4 hours
[tex]c=\sqrt{a^2+b^2}\\\Rightarrow c=\sqrt{30^2+60^2}\\\Rightarrow c=67.08\ \text{km}[/tex]
[tex]c^2=a^2+b^2[/tex]
Differentiating with respect to time we get
[tex]c\dfrac{dc}{dt}=a\dfrac{da}{dt}+b\dfrac{db}{dt}\\\Rightarrow \dfrac{dc}{dt}=\dfrac{a\dfrac{da}{dt}+b\dfrac{db}{dt}}{c}\\\Rightarrow \dfrac{dc}{dt}=\dfrac{30\times -20+60\times 15}{67.08}\\\Rightarrow \dfrac{dc}{dt}=4.47\ \text{km/h}[/tex]
The rate at which the distance between the ships is changing at 4 PM is [tex]4.47\ \text{km/h}[/tex].
How does the force of gravity and the force of earth contribute to africa's poverty?
Answer:
The force of gravity is not the same as being on the earth. when your on the earth there no gravitational pull its all up to the air
Explanation:
No explanation
a 7 kg object moving 10 m/s Right collides with a 14 kg object at rest. If after the collision the 7kg object is at rest and the 14 kg object is moving, what is the velocity of the 14 kg object after the collision?
Answer:
v2(final)=5 m/s
Explanation:
we are going to use the conservation of momentum here
m1*v1(initial)+m2*v2(initial)=m1*v1(final)+m2v2(final)
m1=7 kg v1(initial)=10 m/s
m2=14 kg v2(initial)=0 m/s (bc initially it is at rest)
v1(final)= 0 m/s (m1 stops moving after the collision)
v2(final)=?
7*10+14*0=7*0+14*v2(final)
70=14v2(final)
v2(final)=70/14 m/s=5 m/s
Basic Science!! Helppp
a glass rod is given a positive charge by rubbing it with silk. how did the rod become positive ?
Answer:
When the glass rod is rubbed with silk, the silk strips electrons from the rod, leaving it a positive charge. When the hard rubber rod is rubbed with wool, it gains electrons from the wool, gaining a negative charge.
Explanation:
The low pressure area near Earth's equator is filled by cool air moving in from
А
Europe and South America
B
the North and South Pole
с
the Prime Meridian
D
the Atlantic and Pacific Ocean
Two students are sitting 1.50 m apart. One student has a mass of 70.0 kg and
the other has a mass of 52.0 kg. What is the gravitational force between them?
A. 8.01 x 10-9
B. 1.08 x 10-2
C. 2.28 x 10-8
Answer:
B
Explanation:
What causes an electric field?
Answer: The electric field is produced by stationary charges, and the magnetic field by moving charges (currents); these two are often described as the sources of the field. ... The force created by the electric field is much stronger than the force created by the magnetic field.
Explanation: An electric field is an invisible force field created by the attraction and repulsion of electrical charges (the cause of electric flow), and is measured in Volts per meter (V/m).
Answer:
The electric field is produced by stationary charges, and the magnetic field by moving charges (currents); these two are often described as the sources of the field. The force created by the electric field is much stronger than the force created by the magnetic field.
Explanation:
Ggl
A car driver spends 3hrs driving at an average speed of 80km/hr, stops for 30 minutes to
have some rest, and then drives at an average speed of 90km/hr for 2 hours.
Calculate the average speed during the whole journey
Answer:
The average speed throughout the journey was 76.36 kilometers per hour.
Explanation:
Given that a car driver spends 3hrs driving at an average speed of 80km / hr, stops for 30 minutes to have some rest, and then drives at an average speed of 90km / hr for 2 hours, to determine the average speed during the whole journey the following calculation must be performed:
80 km / h x 3 = 240 km
90 km / h x 2 = 180 km
240 + 180 = 420 km
3 + 2 + 0.5 = 5.5 hours
420 / 5.5 = 76.36
Thus, the average speed throughout the journey was 76.36 kilometers per hour.
An enormous thunderstorm covers Dallas-Ft. Worth. Your best friend Clark is a storm chaser and heads to the center of the storm to take some readings while you stay dry at home. While Clark is at the center of the storm, he sees and hears lightning strike a tree that is 150 m from where he is standing. You are 127 km from the tree. How long does it take for the sound to reach Clark
Answer:
t = 0.437 s
Explanation:
The speed of sound is a constant that is worth v = 343 m / s
v = d / t
t = d / v
the time it takes for the sound to reach Clark at d = 150 m is
t = 150/343
t = 0.437 s
This same sound takes much longer to reach you
t₂ = 127 10³/343
t₂ = 370 s
2.- a person weighing 70 kg travels at 2m / s. What is the value of his kinetic energy?
Answer:18 watts
Explanation:i just got this question trust me
\
Students are asked to design an experiment to confirm that the pressure and volume of an ideal gas are inversely proportional. They use a cylinder containing an ideal gas that has a plunger equipped with a pressure sensor. They perform several trials, and in each trial they start with the gas at the same initial pressure and volume. The students then quickly push the plunger so that the gas achieves a different final pressure and volume. After analyzing their results, they determine that the final pressures and volumes do not follow an inversely proportional relationship. Which of the following refinements to the procedure would show the inverse proportionality between pressure and volume?
A. Compress the gas slowly so that the temperature remains constant.
B. Perform more trials to obtain more data points.
C. Discard data points that do not show inverse proportionality between pressure and volume.
D. Compress the plunger even faster so that the compression is effectively instantaneous.
Answer:
the answers the correct one is A
Explanation:
Let's analyze the situation, the expression for ideal gases is
PV = n R T
in this case n is the number of moles of the gas remains constant, so we see that there is a relationship between volume, pressure and temperature.
For the experiment we are conducting we must ensure that the temperature remains constant, one way to achieve this is by placing a small thermometer on the surface of the cylinder.
By rapidly compressing part of the work done, it is converted into internal energy of the gas molecules, and from there it is transformed into its temperature. One way to reduce this effect is to COMPRESS SLOWLY and thus keep the temperature constant.
This method of allowing to check
P V = cte
when checking the answers the correct one is A
A car is moving around a circular track of radius 25m with a speed of 30 m/s. What is the centripetal acceleration of the car? *
A 72 m/s2
B 36 m/s2
C 30 m/s2
D 6 m/s2
Answer:
I don't know how to do it the subject
The centripetal acceleration of the car when there is the radius and the speed is given so it should be considered as the option b. 36 [tex]m/s^2[/tex].
Calculation of the centripetal acceleration of the car:Since
The radius is 25 cm and the speed should be 30 m/s
Now the following formula should be used
Acceleration = speed^2/ radius
= 30^2 / 25
= 900 / 25
= 36 [tex]m/s^2[/tex]
Therefore, The centripetal acceleration of the car should be considered as the option b. 36 [tex]m/s^2[/tex].
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A child of mass 51.9 kg sits on the edge of a merry-go-round with radius 2.4 m and moment of inertia 215.24 kg m2 . The merry go-round rotates with an angular velocity of 2.1 rad/s. The child then walks towards the center of the merry-go-round and stops at a distance 0.864 m from the center. Now what is the angular velocity of the merry-go-round
Answer:
4.25 rad/s
Explanation:
Given that.
Mass, m = 51.9 kg
Radius, r1 = 2.4 m
Moment of inertia, I = 215.24 kgm^2
Angular velocity, ω = 2.1 rad/s
Radius, r2 = 0.864 m
To start with, we are going to use the Conservation of angular momentum to solve the question, which is
l(initial) = l(final)
[I₁ + I₂](initial)*ω(initial) = [I₁ + I₂](final)*ω(final)
Making ω(final) the subject of formula, we have
ω(final) = [I₁ + I₂](initial)*ω(initial) / [I₁ + I₂](final)
ω(final) = [215.24 + (51.9)(2.4)²](2.1) / [215.24 + (51.9)(0.864)²]
ω(final) = [215.24 + 298.944]2.1 / [215.24 + 38.74]
ω(final) = 514.184 * 2.1 / 253.98
ω(final) = 1079.786 / 253.98
ω(final) = 4.25 rad/s
= 5.273 rad/s
Which of the following best defines
weather?
A. the expanding or contracting of the atmosphere
B. the measurement of the amount of water vapor in the
atmosphere
C. the condition of the atmosphere at a certain time and
place
Help Resources
D. the average air temperature of a specific region
Answer:
I'd say D
Explanation:
because not all weather happens within the atmosphere, and most weather depends on region (lile if your near the equator or not)
An astronaut who is repairing the outside of her spaceship accidentally pushes away a 92.9 cm long steel rod, which flies off at 12.5 m/s , never to be seen again. As it happens, the rod is oriented perpendicularly to the magnetic field in that region of space. The rod is moving perpendicularly to its length as well as to the direction of the magnetic field. The magnetic field strength there is 6.23 mT . What is the magnitude of the EMF, in millivolts, induced between the ends of the rod
Answer:
V = 0.0723 volts = 72.3 milivolts
Explanation:
The emf induced in the rod is the motional emf due to the magnetic field. This motional emf can be calculated by the following formula:
[tex]EMF = V = vBl Sin\theta[/tex]
where,
V = Motional EMF = ?
v = speed of rod = 12.5 m/s
B = Magnetic Field = 6.23 mT = 0.00623 T
l = Length of rod = 92.9 cm = 0.929 m
θ = angle between v and B = 90°
Therefore,
[tex]V = (12.5\ m/s)(0.00623\ T)(0.929\ m)Sin\ 90^o\\[/tex]
V = 0.0723 volts = 72.3 milivolts
Which of these cubes absorb the most light?
Answera black cube or dark colors cause dark colors suck in heat