6. The first vertebrates appeared during
a. Precambrian time
b. the Paleozoic Era
C. the Mesozoic Era
d. The Cenozoic Era

Answers

Answer 1

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.


Related Questions

Which ball moved at the same speed as Ball 3?

Answers

Answer:

you forgot to attach the image

a bicycle uniformly from rest at time t the velocity of the bicycle is v at what time will the bicycle have a velocity of 4v​

Answers

Here

Acceleration and initial velocities are constant.

According to first equation of kinematics.

[tex]\\ \sf\longmapsto v=u+at[/tex]

[tex]\\ \sf\longmapsto v=0+at[/tex]

[tex]\\ \sf\longmapsto v=at[/tex]

[tex]\\ \sf\longmapsto v\propto t[/tex]

Time was t at velocity vTime will be 4t at velocity 4v

The earth has a mass of 5.972 x 1024 Kg. You decide to
put the satellite in an orbit 400 Km above the surface of the earth which has a radius of 6,371 Km, so the total
distance from the center of the earth to the satellite is 6,771,000 m. What will you need the velocity of the
satellite to be to stay in orbit? Show your work

Answers

Answer:

Explanation:

You want the required centripetal force to equal gravity force

if m is the mass of the satellite

ma = mv²/R

a = v²/R

F = ma = GMm/R²

a = GM/R²

v²/R = GM/R²

v² = GM/R

v = √(GM/R)

v = √(6.674 x 10⁻¹¹(5.972 x 10²⁴)/6.771 x 10⁶)

v = 7.672 x 10³ m/s

What is the unit of pressure
is it P=F/A?

Answers

The SI unit for pressure is the pascal (Pa), equal to one newton per square metre (N/m2, or kg·m−1·s−2). This name for the unit was added in 1971; before that, pressure in SI was expressed simply in newtons per square metre.

Answer:

Units of pressure include: Pa, bar, at, atm, torr, lbf/in^2

Explanation:

P = F/A is a formula for pressure not a unit.

Pa = Pascal

Bar = Bar

at = Technical Atmosphere

Torr = Torr

lbf/in^2 = pounds per square inch

A 2.00 kg rock is dropped from the top of a 30.0 m high building. Calculate the ball’s momentum at the time that it strikes the ground.

Answers

Explanation:

We use the Theorem of conservation of mechanical energy for finding the velocity when it strikes the ground:

Ei = Ef

Ki + Ui = Kf + Uf

Ui = Kf

m g h = 1/2 m v^2

v = sqrt(2gh)

So the momentum will be:

p = mv = m * sqrt(2gh)

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.

Answers

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.

Learn more about the wave mechanical model: https://brainly.com/question/1382157

How do you measure a English saddle to fit your horses?

Answers

Answer:

measure the area in which the rider will sit on, then take those measurements to a person who crafts saddles, tell them the exact measurements. then you wait a while until he/she is done then put the saddle on the horse.

Explanation:

Answer:

Explanation:

The shape of the horse's withers is also a determining factor in choosing a saddle. An adjustable hoop saddle allows you to choose with finesse the opening of the tree at the height of the withers, in order to best adapt to each horse. It is the size of the arch that determines the opening of the saddle.

English saddles are the main riding saddles used in equestrian disciplines around the world: Show jumping, endurance, require specific designs to meet specific needs. For example, dressage saddles are designed to bring the rider closer to the horse, allowing him to communicate very precisely with his horse.

Which variable mentioned in Table 2-1 is kept constant? a. amount of time spent swimming b. type of swimming stroke c. number of calories used d. the person swimming

Answers

Answer:

a. amount of time spent swimming

How much work is done on a 30 kg object when 20 Newton’s of force is exerted for a distance of 5 meters

Answers

Answer:

Work = force * displacement

= 50 N * 20 Meter

=1000 Newton meter = 1000 joule .

Explanation:

PLEASE HELP ASAP
I need help understanding this question, form my guess I’m thinking it’s C but I’m not to sure

Answers

Answer:

Explanation:

Without the diagram, we have to bracket our answers.

Total energy is constant, so we eliminate options A and B.

C is correct if position 1 is closer to the star than position 2

D is correct if position 2 is closer to the star than position 1

The part of the moon that is visible will appear to grow and shrink during the lunar cycle. This occurs in the direction of _____ to _____.

Answers

Answer:

left to right

Explanation:

give me brain pls

Answer:

of the moon to .......

Hey guys can you help me solve this problem "how long will it take a car travelling 30m/s to come to stop ifs its acceleration is -3 m/s2".

Answers

Answer:

10 seconds.

Explanation:

We can use a kinematic equation where we know the final velocity, initial velocity, acceleration, and need to determine the time t:

[tex]\displaystyle v_f = v_i + at[/tex]

The initial velocit is 30 m/s, the final velocity is 0 m/s (as we stopped), and the acceleration is -3 m/s².

Substitute and solve for t:

[tex]\displaystyle \begin{aligned} (0\text{ m/s}) & = (30 \text{ m/s}) + (-3 \text{ m/s$^2$}) t \\ \\ t & = \frac{-30\text{ m/s}}{-3 \text{ m/s$^2$}} \\ \\ & = 10 \text{ s} \end{aligned}[/tex]

Hence, it will take the car 10 seconds to come to a stop.

You have a pendulum clock made from a uniform rod of mass M and length L pivoting around one end of the rod. Its frequency is 1 radian/sec. The pivot breaks. Though the mass change is negligible, you need to rehang the rod halfway between the old pivot point and the middle of the rod. The new oscillation frequency is:
A. 0.88 rad/sec
B. 1.13 rad/sec
C. 1.07 rad/sec
D. 0.92 rad/sec

Answers

The new oscillation frequency of the pendulum clock is 1.14 rad/s.

     

The given parameters;

Mass of the pendulum, = M Length of the pendulum, = LInitial angular speed, [tex]\omega _i[/tex] = 1 rad/s

The moment of inertia of the rod about the end is given as;

[tex]I_i = \frac{1}{3} ML^2[/tex]

The moment of inertia of the rod between the middle and the end is calculated as;

[tex]I_f = \int\limits^L_{L/2} {r^2\frac{M}{L} } \, dr = \frac{M}{3L} [r^3]^L_{L/2} = \frac{M}{3L} [L^3 - \frac{L^3}{8} ] = \frac{M}{3L} [\frac{7L^3}{8} ]= \frac{7ML^2}{24}[/tex]

Apply the principle of conservation of angular momentum as shown below;

[tex]I _i \omega _i = I _f \omega _f\\\\\frac{ML^2}{3} (1 \ rad/s)= \frac{7ML^2}{24} \times \omega _f\\\\\frac{24 \times ML^2}{3 \times 7 ML^2} (1 \ rad/s)= \omega _f\\\\1.14 \ rad/s = \omega _f[/tex]

Thus, the new oscillation frequency of the pendulum clock is 1.14 rad/s.

Learn more about moment of inertia of uniform rod here: https://brainly.com/question/15648129

Which of the following statements is NOT true of a hypoosmotic solution?
A. It is also known as a hypotonic solution.
B. There are more dissolved solids within the cell than outside the
cell.
C. It may cause water to move into the cell, which will cause it to
swell.
D. It may cause the cell to shrink or crenate.

Answers

There are more dissolved solids within the cell than outside thecell.

Answer:

Good luck on the test, you donuts.

Explanation:

A change in momentum is also called:
a. Impact
b. Imput
c. Impulse
d. Impole

Answers

Answer:

c. Impulse

Explanation:

At the end of meiosis II, the new haploid cells in humans are known as which of the following?
Diploid cells
Embryo
Zygotes
Gametes

Answers

Diploid cells. Is the answer

i need some help getting started on an essay for physics. i decided on the topic of roller costers and dont know how to start it. see the image on my requirements.​

Answers

Explanation:

force , motion , electric current

Please help me answer the following question!

What is the momentum of a 750-kg Volkswagen Beetle when at rest?
Please give the Value and Unit

Answers

Answer:

P = 0

Explanation:

Momentum is defined as the quentity of motion contained in a body. Mathematically, it can be defined as the product of mass and velocity. So, in order to determine the Volkswagen Beetle, at rest, we can use the simple formula, as follows:

where,

P = Momentum of Volkswagen Beetle = ?

m = Mass of Volkswagen Beetle = 750 kg

v = Velocity of Volkswagen Beetle = 0 m/s (since, it is at rest)

Therefore,

P =

explain how water erosion changes land forms

Answers

Answer:

Water erosion can slowly wash away dirt and rocks, wearing away landforms and sometimes forming rivers that can even carve out stone over time.

During a car accident on the NJ Turnpike, the airbags deploy. A 79 kg passenger traveling at 32 m/s makes impact with the airbag over a time of 0.25 seconds. What
was the impact force experienced by the passenger?

Answers

Hi there!

Recall that:

Impulse = Δ in momentum = mΔv

Impulse = Force · time

Begin by calculating the change in momentum, or impulse.

I = mΔv = m(vf - vi)

I = (79)(0 - 32) = -2528 Ns

Now, we can use the equation relating force and time to impulse.

I = Ft

Rearrange for time:

I/F = t

-2528/0.25 = -10112 N

**OR, if magnitude ⇒ |-10112| = 10112 N

3. Particles carrying no charge ____________

Answers

Answer:

Neutrons

Explanation:

Predict changes in state according to change in particle motion. Know the vocabulary used to describe changes of state.

Answers

The change in the state of matter causes change in the motion of the particles of the matter. The gaseous state of matter has the greatest speed while the solid state has the least speed.

The change in state of every matter is accompanied by lost or gained of energy.

Example is water.

The solid state of water is ice. The motion of particles of the water is relatively zero because the molecules are held at a fixed position.

The liquid state of water occurs when the temperature of the ice is increased above zero degree Celsius. The speed of the particles of water in liquid state is greater than solid state.

The gaseous state of water occurs when the temperature of the liquid water is increased beyond 100 degree Celsius. The speed of water in gaseous state is greater than liquid state.

Learn more about different state of matter here: https://brainly.com/question/9402776

objects want to ______ ___________ doing what they're __________ ____________ because they are "lazy." This is called __________.

Answers

Answer:

Explanation:

Objects want to continue doing what they're already doing because they are "lazy." This is called inertia.

What is the significance of Isaac's name?

Answers

[tex] \large \bf{Answer:-}[/tex]

The name Isaac means “one who laughs” or “one who rejoices.” In the Old Testament of the Bible, Isaac is the firstborn son of Abraham. He is one of the three biblical patriarchs revered by Jews, Christians, and Muslims.

Zoe is setting up a track for a toy car. The track has a ramp that is 32° above horizontal. If Zoe wants the car to travel as a projectile for 1.0 seconds, how fast does the toy car need to be moving as it leaves the ramp?
4.9 m/s
1.0 m/s
9.2 m/s
7.4 m/s m

Answers

Answer:

Explanation:

Not enough information.

IF we ASSUME she wants the car to be at LAUNCH LEVEL after 1 second of flight.

THEN

The highest point will have zero vertical velocity and will have taken ½ second to get there. This means that the initial vertical velocity was

v = gt

vy₀ = 9.8(0.5)

vy₀ = 4.9 m/s

vsinθ = vy₀

v = vy₀/sinθ

v = 4.9/sin32

v = 9.2466...

v = 9.2 m/s

True or False. Isaac at first resisted his father's command to be the sacrifice.

Answers

False, he never resisted. He lay still, allowing himself to be tied.

A car accelerating from rest for 20s to reach velocity of 15 m/s and it keeps on. moving with this velocity for 50s an then it applied the break
Stop in 30s what is the displacement?

WILL GIVE BRAINLY best answer with steps

Answers

Answer:

1125m

Explanation:

The car moves with a uniformly accelerated motion for 20s:

s = 1/2·a·t² + v0·t + s0 (note that vo = 0 and s0 = 0, with v0 being the initial velocity and s0 the initial displacement).

So: s = 1/2·a·t²

The acceleration will be: Δv/Δt = 15m/s / 20s = 0.75 m/s²

s1 = 1/2·0.75 m/s² · (20 s)^2 = 150m

Then it continues with the velocity he acquired (v = a·t = 0.75 m/s²·20s = 15 m/s):

s2 = vt = 15m/s·50s = 750m

The final acceleration, when stopping, will be:

a = Δv/Δt = -15m/s / 30s = -1/2 m/s²

s3 = 1/2·(1/2m/s²)·(30s)² = 225m.

Now we sum s1 with s2 and s3:

s1 + s2 + s3 = 150m + 225m + 750m = 1125m

What do these weapon stats mean?

Idle sway control is measured in Fc???

Flinch resistance is measured in N.

Answers

Answer:

its sort of like how Pounds are measured in lbs

Explanation:

Pounds are measured in lbs when they dont sound anything similar, same thing applies to gun technology.

A dwarf planet has a mass of 0.0045 times that of the Earth and a diameter on average 0.19 times that of the Earth. What is the escape velocity of the dwarf planet? (Type in the numerical answer and unit, e.g. 10m/s)

Answers

The escape velocity of the dwarf planet is 1,721.8 m/s.

The given parameters:

Mass of the dwarf planet, m = 0.0045 MMass of the Earth = 5.98 x 10²⁴ kgDiameter of the planet, d = 0.19 DDiameter of the Earth, D = 12,742 km

The mass of the of the dwarf planet is calculated as follows;

[tex]m = 0.0045 \times 5.98 \times 10^{24} \ kg\\\\m = 2.69\times 10^{22} \ kg[/tex]

The radius of the dwarf planet is calculated as follows;

[tex]r = \frac{0.19 D}{2} \\\\r = \frac{0.19 \times 12, 742, 000}{2} \\\\r = 1,210,490 \ m[/tex]

The escape velocity of the dwarf planet is calculated as follows;

[tex]v _e = \sqrt{\frac{2GM}{r} } \\\\v_e = \sqrt{\frac{2\times 6.67 \times 10^{-11} \times 2.69 \times 10^{22}}{1,210,490}}\\\\v_e = 1,721.8 \ m/s[/tex]

Learn more about escape velocity here: https://brainly.com/question/13726115

A 1250 kg car is stopped at a traffic light. A 3550 kg truck moving at 8.33 m/s strikes the car from behind, causing the bumpers to lock together.

A) What is the momentum of the car-truck system before the collision?

B) What is the momentum of the car-truck system after the collision?

C) How fast do the car and truck move after the collision?

(Do NOT put any links or reproductions, I just need help with this.)​

Answers

A) Before the collision, the total momentum is

(1250 kg) (0 m/s) + (3550 kg) (8.33 m/s) ≈ 29,600 kg•m/s

B) Momentum is conserved, so after the collision it is still approximately 29,600 kg•m/s.

C) If v is the speed of the locked car-truck system, then

(1250 kg) (0 m/s) + (3550 kg) (8.33 m/s) = (1250 kg + 3550 kg) v

Solve for v :

29,571.5 kg•m/s = (4800 kg) v

v ≈ 6.16 m/s

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