Answer:
b. the Paleozoic Era
Explanation:
The first vertebrates to appear are primitive fish in the Cambrian Period, but bony fishes with actual bony vertebratae didn't appear for another 100 million years. The Cambrian Period is the first of three periods in the Paleozoic Era. The Cambrian explosion was an event when practically all major animal phyla started appearing in the fossil record.
A body with a uniform acceleration travels distances of 24m and 64m during the first two equal consecutive intervals of time, each of duration 4s. Determine the initial velocity and acceleration of the moving body.
Answer:
Explanation:
Average velocity in the 24 m interval is 24 / 4 = 6 m/s
Average velocity in the 64 m interval is 64 / 4 = 16 m/s
There is a 4 second interval between the two points where average velocity equals actual velocity
a = Δv/t = (vf - vi) / t = (16 - 6) / 4 = 2.5 m/s²
s = v₀t + ½at²
24 = v₀(4) + ½(2.5)4²
4v₀ = 24 - 20
v₀ = 1 m/s
Not asked for but the velocity at the end of the first segment and beginning of the second segment is 11 m/s and final velocity is 21 m/s
True or False. Father of a multitude" obeyed God's command to kill His son because the Ten Commandments had not yet been given.
Answer:
Explanation:
The father of the Multitude was Abraham. And he did precede the 10 commandments. But the story really has nothing to do with the 10 commandments.
He obeyed God's Command because it was God who issued it. Abraham had complete faith in God's ability to make things come out right. The sacrifice of Isaac was a test of faith.
I would advise you to answer true, but whoever wrote the question employed a twisted kind of logic. The sacrifice of Isaac had nothing to do with the 10 commandments. Thou Shalt not murder is not really covered by this circumstance.
So true might not be the correct answer. The question is very complex and does not lend itself to a simple True/ False answer.
Can someone help me solve this problems please? It's a physics problem.
Answer:
i cant see
Explanation:
but im smart
. Boa constrictor snakes have tiny pelvic girdles and leg bones within their bodies. Since these structures are not functional, they are called *
a. vestigial
b. analogous
c. maladaptive
d. homologous
Those organic structures that do not seem to play any important biological function in the organism that possesses them are known as vestigial structures.
What is a vestigial structure?A vestigial structure is one that has atrophied or lost its original function throughout the course of evolution.
It generally refers to those organic structures that were useful at some point, but are now practically or totally useless.These structures are preserved as an inheritance of the evolutionary process, because at some point an ancestor of the current species had that structure, which was functional, but it ceased to be important and would end up atrophy.Therefore, we can conclude that vestigial structures are structures that some organisms still conserve as an inheritance from their ancestors but that, for some reason or another, are no longer useful for the functioning of the same.
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if the force acting on a body of mass 40 k.g is doubled by how much will the acceleration change
Answer:
Explanation:
Ignoring friction, the acceleration will double
F = ma
2F = m(2a)
Identify the types of motion:-
the movement of the snail on the ground
the strings of the guitar
the whirling of stone tied with a thread
Answer:
the movement of snail on the ground is in random motion.
the strings of the guitar is in oscillatory motion.
the whirling of stone tied with a thread is in circular motion.
A 1.2 kg hammer slams down on a nail at 5.0 m/s and bounces off at 1.0 m/s. If the impact lasts 1.0 ms, what average force is exerted on the nail?
Answer:
Explanation:
Impulse results in a change of momentum
FΔt = mΔV
F = mΔV/Δt
The impulse acting on the hammer will equal the impulse acting on the nail
If we assume upward is the positive direction
F = m(vf - vi)/t
F = 1.2(1.0 - (-1.5)) / 0.001
F = 3000 N
A 1.2 kg hammer slams down on a nail at 5.0 m/s and bounces off at 1.0 m/s, if the impact lasts 1.0 ms, so the average force exerted on the nail is 3000 N.
What is average force?According to Newton's third law, there is an equal and opposite force for every force. The hammer's force on the nail will be identical in size to the nail's force on the hammer, but opposite in direction.
Momentum shifts as a result of impulse.
FΔt = mΔV
F = mΔV/Δt
The force exerted on the hammer will be equivalent to the force exerted on the nail.
m(vf - vi)/t = F
F = 1.2(1.0 - (-1.5)) / 0.001
F = 3000 N
Therefore, F = 3000 N, if A 1.2 kg hammer slams down on a nail at 5.0 m/s and bounces off at 1.0 m/s, if the impact lasts 1.0 ms.
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This is physics and it says collision and elastic/inelastic i need help
The initial velocity of the 3250 Kg mass is 2.1 m/s. The distance covered by the larger mass in 5s is 4.7 cm.
In this problem, we have to apply the law of conservation of linear momentum. Note that;
Momentum before collision = Momentum after collision
m1u1 + m2u2 = m1v1 + m2v2
(2150 × 10) + (3250u1) = (2150 + 3250)5.22
21500 + 3250u1 = 5400 × 5.22
3250u1 = 28188 - 21500
u1 = 28188 - 21500/3250
u1 = 2.1 m/s
2) Again from the principle of conservation of linear momentum;
(0.40 × 3.5) + (0.60 × 0) = (0.40 × 0.70) + (0.60 × v2)
1.4 = 0.28 + 0.60v2
1.4 - 0.28 = 0.60v2
v2 = 1.87 cm/s
Using;
s = 1/2 ( u + v)t
s = 1/2(0 + 1.87) × 5
s = 4.7 cm
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A gold fish weighing 13g has a speed of 8.8m/s. What is its Kinetic energy
Answer:
0.47 J
Explanation:
A swimmer who can swim in still water at a speed of 4km/h is swimming in a river. the river flows at a speed of 3km/h. calculate the speed of the swimmer relative to the river bank when she swims:- 1. downstream 2.upstream
Explanation:
Downstream: you just sum the magnitude of the velocity vectors:
3km/h + 4km/h = 7km/h
Upstream: difference of the magnitudes of the velocity vectors, in absolute value:
|3km/h - 4km/h| = 1km/h
A block of wood
wood, with mass 1.34 kg rests stationary
on horizontal ground.
The coefficient of Kinetic
friction between the block and the ground is 0.966.
A bullet, with mass 0.250kg, moving horizontally
hits and sticks into the block of wood. We find
that the speed of the block of wood, with the
ballet embedded in it, just after collision is 11.9 m/s.
A) calculate the speed of the bullet before hitting the block of wood.
it, just after the collision
is 11-9mis.
as calculate the speed of the bullet before
s
hitting the block of wood.
Answer:
Explanation:
conservation of momentum
m(u) + M(0) = (m + M)v
u = (m + M)v/m
u = (0.250 + 1.35)(11.9) / 0.250
u = 76.16
u = 76.2 m/s
That's a fairly massive, and slow, bullet.
a spring with a spring constant of 65 n/m is displaced -94cm. what is the magnitude of the force exerted by the spring
Answer:
Explanation:
F = kx = 65 N/m(0.94 m) = 61.1 = 61 N
A wire that is 1.0 m long with a mass of 90 g is under a tension of 710 N. When a transverse wave travels on the wire, its wavelength is 0.10 m. What is the frequency of this wave?
Answer:
890 HzI hope you liked my answer. Thank You!
What is the significance of Isaac's name? What is the significance of Isaac's name?
Answer:
Isaac is one of the three patriarchs of the Israelites and is an important figure in the Abrahamic religions, including Judaism, Christianity, and Islam. Isaac's name means "he will laugh", reflecting the laughter, in disbelief, of Abraham and Sarah, when told by God that they would have a child.Hope this helps !!Explanation:
Itz Deepika Here to help ~ .
Note:- If you have more questions then let me know !!
A block slides on a rough 45 degree incline. The coefficient of friction is µk what is the ratio of acceleration when the block accelerates down the incline to the acceleration when the block is projected up the incline
Answer:
[tex]\frac{a_{d}}{a_{i}} = \frac{(1 -mu)}{mu}[/tex]
= (1 - μ)/μ
Explanation:
Always draw a diagram!
Up the incline:
[tex]Fr_{max}[/tex] = maximum friction
[tex]Fr_{max}[/tex] = μk
k = R = mg.cos(45) = mg.sin(45)
Resolution of forces parallel to the slope:
F (Fp in the diagram) = force of propulsion
g = gravity
[tex]F - Fr_{max} = ma_{i}[/tex]
[tex]F -[/tex] μ.mg.cos(45) [tex]= ma_{i}[/tex]
Down the decline:
Resolution of forces:
[tex]mg.sin(45) - Fr_{max} = ma_{d}[/tex]
[tex]mg.sin(45) -[/tex] μ.mg.cos(45) [tex]= ma_{d}[/tex]
Then, find the ratio:
[tex]\frac{ma_{d}}{ma_{i}} = \frac{mg.sin(45) - mu.mg.cos(45)}{-F + mu.mg.cos(45)} \\\\ \frac{a_{d}}{a_{i}} = \frac{k - k.mu}{-F + k.mu} \\\\ = \frac{k(1 -mu)}{-F + k.mu}[/tex]
Potentially, there is no need to consider F in this situation, in which case:
[tex]\frac{a_{d}}{a_{i}} = \frac{k(1 -mu)}{k.mu} \\\\ = \frac{(1 -mu)}{mu}[/tex]
= (1 - μ)/μ
I need help with parts a and B of this question
Answer:
Explanation:
Let x be the leaf spring compression distance
F = kx
5.20 x 10⁵ = (5.45 x 10⁵)x + (3.80 x 10⁵)(x - 0.500)
5.20 x 10⁵ = (5.45 x 10⁵)x + (3.80 x 10⁵)(x) - 1.90 x 10⁵
7.10 x 10⁵ = (9.25 x 10⁵)x
x = 0.76756...
x = 0.768 m
W = ½(5.45 x 10⁵)0.768² + ½(3.80 x 10⁵)(0.768 - 0.500)²
W = 174,148.648648...
W = 174 KJ
Which of the following changes would decrease the force between two charged particles by a factor of 9? A. Decreasing the distance between the particles by a factor of 3 B. Increasing the distance between the particles by a factor of 3 C. Increasing the amount of charge on each particle by a factor of 9 D. Decreasing the amount of charge on one of the particles by a factor of 3
Option B is correct.Increasing the distance between the particles by a factor of 3 decrease the force between two charged particles by a factor of 9.
What is electric force?The electric force between the two charges is directly proportional to the product of the charge and inversely proportional to the square of the distance between them.
The electric force is found as;
[tex]\rm F = \frac{K q_1q_2}{r^2}[/tex]
The electric force between the two charges is directly proportional to the product of the charge.
The electric force is inversely proportional to the square of the distance between them.
Increasing the distance between the particles by a factor of 3 decreases the force between two charged particles by a factor of 9
Hence, option B is correct.
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HELP PLEASE WILL MARK BRAINLIEST
Outside wooden steps may get slippery when they are wet. How could you make them less slippery?
There are many ways you can get wooden steps to be less slippery even when they are wet. Some ways are:
*You can put a carpet on the steps. The fibers in a carpet usually have some friction which will give you a grip as you climb up and/or down and prevent you from falling.
*You can apply anti-slip coatings like a paint on the steps. If you add some sand to the paint to add traction and lessen the slippery nature. Alternatively, If the wood has been waxed, you may consider using a wax remover.
*You can fix a hand railing so that you can hold on to it when you go up and down the steps.
7. Which of the following explains how radiometric dating is used to estimate absolute
age.
a. By comparing how deep in the curst the radioactive material in a sample of rock
is, scientists can calculate the length of time since the rock formed.
b. By comparing the amount of organic material in a sample of rock, to the known
rate of decay of the parent rock, scientists can calculate the length of time since
the rock formed.
C. By comparing the amount of radioactive material in a sample of rock, to the
surrounding rocks, scientists can calculate the length of time since the rock
formed.
d. By comparing the amount of a radioactive material in a sample of rock, to the
know rate of decay of the parent rock, scientists can calculate the length of time
since the rock formed.
Answer:
d.
Explanation:
Radiometric dating is a method of dating geological/ archaeological specimens by determining the relative proportions of particular radioactive isotopes present in a sample. Carbon dating is a form of radiometric dating, but, in choice b, you're not comparing the carbon to the rock. One would compare ¹⁴C levels within the organic compound, just as one would compare radioactive isotope levels in a rock.
17. The shape of a river is determined by which of the following? (Choose all that
apply)
A Erosion
B. Deposition
C. Weathering
D. water speed
Answer:
Water speed Plays a key role In determining The shape of it
The graph below shows the variation with distance r from the nucleus of the square of the wave function, Ψ^2, of a hydrogen atom according to Schrödinger theory.
A. is most likely to be near a.
B. is always a.
C. is always less than a.
D. is always greater than a.
The region a represents the distance of the electron from the nucleus.
According to the wave mechanical model of the atom, the probability of finding an electron within a given volume element (representing the atom) is the square of the wave function psi.
Since a is the region in space where there is the greatest probability of finding the electron in the atom, it follows that distance of the electron form the atom is always a.
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a uniform thin rod of length l and mass m is allowed to rotate on a frictionless pin passing through one end. The rod is released from rest in the horizontal position. a.) What is the speed of the center of gravity when the rod reaches its lowest position? b.) What is the tangential speed of the lowest point of the rod when the rod reaches its lowest position?
Answer:
Explanation:
Potential energy gets converted to rotational kinetic energy
a) ½Iω² = mgh
½(mL²/3)ω² = mgL/2
(L/3)ω² = g
ω = [tex]\sqrt{3g/L}[/tex]
v(CG) = (L/2) [tex]\sqrt{3g/L}[/tex]
Not sure if you wanted angular speed or tangential speed of the CG so I gave both.
b) v = Rω = L [tex]\sqrt{3g/L}[/tex]
the driver of a 2.0 × 10³ kg red car traveling on the highway at 45m/s slams on his brakes to avoid striking a second yellow car in front of him, which had come to of because locking ahead.After the brakes are applied a constant friction force of 7.5 × 10³ N acts on the car ignore air resistance.
a₎ Determine the least distance should the brakes be applied to avoid a collision with the other vehicle?
Answer:
Explanation:
a = F/m = 7500/2000 = 3.75 m/s²
v² = u² + 2as
s = (v² - u²) / 2a
s = (0² - 45²) / (2(-3.75))
s = 270 m
A woman skis from rest down a hill 20 m high. If friction is negligible, what is her speed at the bottom of the slope? Select one: O a. 20 m/s O b. 12 m/s O c. 400 m/s O d. 6 m/s
Hi there!
We can use the work-energy theorem to solve.
Recall:
[tex]\large\boxed{E_i = E_f}}[/tex]
Initial energy = final energy
The initial energy is purely potential (she starts from rest), and, if we assign the bottom of the slope as the 0 line, her energy at the bottom is purely kinetic.
PE = mgh
KE = 1/2mv²
We can begin by setting the two equal:
mgh = 1/2mv²
Cancel out the mass and rearrange to solve for velocity:
2gh = v²
v = √2gh
Plug in given values and use g ≈ 10 m/s²:
v = √2(10)(20) = 20 m/s
If a force of 50 Newton's was applied to an object with a mass of 5 kilograms, what will the object's acceleration be?
A force of 50 N was applied to an object with a mass of 5 kg, then the acceleration of the object will be 10 m/s².
What is Acceleration?The rate of change in an object's velocity with respect to time is known as acceleration in mechanics. The vector quantity of accelerations. The direction of the net force that is acting on an object determines its acceleration.
Since acceleration has both a magnitude and a direction, it is a vector quantity. Velocity is a vector quantity as well. The definition of acceleration is the change in velocity vector over a time interval divided by the time interval.
There are several types of acceleration :
Uniform AccelerationNon-Uniform AccelerationAverage AccelerationAccording to the question, the given values are :
Force, F = 50 N
Mass, m = 5 kg
Force = m × a
a = 50 / 5
a = 10 m/s².
Hence, the acceleration of the object will be 10 m/s².
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Select the correct answer. Chloe is playing the flute some distance away from a crowd. If the atmospheric temperature is 15°C, what is the speed of the sound traveling from the flute? A. 340 meters/second B. 330 meters/second C. 320 meters/second D. 310 meters/second E. 300 meters/second
Answer:
A. 340 meters/second
I think this is the right answer.
How much work is done on a 30 kg object when 20 Newton’s of force is exerted for a distance of 5 meters
Answer:
Work = force * displacement
= 50 N * 20 Meter
=1000 Newton meter = 1000 joule .
Explanation:
If the speed of the magnet is doubled, the induced voltage is ________ . twice as great four times as great half as great unchanged
If the speed of the magnet is doubled, the induced voltage is twice as great
Faraday's law of induction states that whenever relative motion exists between a coil and magnetic field, a voltage will induce in the circuit and this voltage is proportional to the rate of change of the flux. The expression for the motional emf is as follows:
ε=Blv
Here, ε is the motional emf, B is the magnetic field, l is the length of the conductor, and v is the velocity at which the magnetic field changes.
The induced voltage by the moving magnet is directly proportional to the speed of the magnet. Therefore, an increase in the speed of the magnet will increase the induced voltage.
If the speed of the magnet is doubled, the induced voltage is twice as great
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Anita Knapp needs to get hay to cows in a frozen field using an airplane flying 80.0 m/s, at a height of 300,m. If at the last minute, how far from the cow would she have to release the hay in order to hit the cow? *
Answer:
Explanation:
If we ignore wind resistance, the time needed for the hay to drop from vertical rest is
t = √(2h/g) = √(2(300)/9.81) = 7.82 s
d = vt = 80.0(7.82) = 626 m before passing over the cow.
How can whales descend quickly and face no problems
Answer:
Whales face an increasing number of threats including: For hundreds of years people hunted whales for their oil to fuel lamps and candles, to lubricate machinery and to make margarine, lipsticks and other products. They also used baleen whales to make tennis racquets and corsets!
Explanation: