Answer:
v = 340 m/s
Explanation:
Given that,
A herdsman yelling out to a fellow herdsman heard his voice reflected by a cliff 4s later.
The cliff is 680 m away
We need to find the velocity of sound in air.
Velocity = distance/time
Distance = 2 × 680 = 1360 m
[tex]v=\dfrac{1360\ m}{4\ s}\\\\=340\ m/s[/tex]
So, the velocity of sound in air is 340 m/s.
The agonist in a movement is the muscle that provides the major force to complete the movement
(A)True
(B)False
A squirrel jumps into the air with a velocity of 4 m/s at an angle of 50%. What is the maximum height reached by the squirrel?
The maximum height reached by the squirrel : 0.479 m
Further explanationGiven
vo= 4 m/s
θ = 50 °
Required
The maximum height
Solution
Parabolic motion :
[tex]\tt h_{max}=\dfrac{v_o^2sin^2\theta}{2.g}[/tex]
Input the value
[tex]\tt h_{max}=\dfrac{4^2\times (sin~50)^2}{2\times 9.8}\\\\h_{max}=0.479~m[/tex]
or you can use
Find t from vt= vo sin θ - gt(negative sign=against gravity)⇒vt=0 at peak(the maximum height)
and input t to vertical component : y=voy.t-1/2gt²
Evidence supporting the theory of continental drift includes:
a.
b.
c.
d .
Answer:
The apparent fit of the eastern coastline of South America and western coastline of Africa
Similarities of plants and animal fossils in South America and some parts of African continent which were separated by a vast ocean
Similarities in the sequence of rock layers of opposite sides of the Atlantic Ocean
why is it difficult to lift out the bucket form well
because of gravitional pull
a machine
of efficiency of 70% is used to raise
a body of
mass 80 kg through
a vertical distance of 3m in
40 seconds. Calculate the power input. (Take g = 10 m/s²)
Answer:
Power_input = 85.71 [W]
Explanation:
To be able to solve this problem we must first find the work done. Work is defined as the product of force by distance.
[tex]W = F*d[/tex]
where:
W = work [J] (units of Joules)
F = force [N] (units of Newton)
d = distance [m]
We need to bear in mind that the force can be calculated by multiplying the mass by the gravity acceleration.
Now replacing:
[tex]W = (80*10)*3\\W = 2400 [J][/tex]
Power is defined as the work done over a certain time. In this way by means of the following formula, we can calculate the required power.
[tex]P=\frac{W}{t}[/tex]
where:
P = power [W] (units of watts)
W = work [J]
t = time = 40 [s]
[tex]P = 2400/40\\P = 60 [W][/tex]
The calculated power is the required power. Now as we have the efficiency of the machine, we can calculate the power that is introduced, to be able to do that work.
[tex]Effic=0.7\\Effic=P_{required}/P_{introduced}\\P_{introduced}=60/0.7\\P_{introduced}=85.71[W][/tex]
Helppppp meeee plssss ASAP
Suppose the atoms of two different nonmetal elements bonded. What type of
substance would most likely form?
A. A metalloid
B. An ionic compound
C. A covalent compound
D. A third element
Answer:
C
Explanation:
covalent. Hope that helps!
What is the mechanical advantage of the inclined plane below?
a) 2.6
b) 0.8
c) 2.4
d) 0.6
Answer;
2.6
Explanation;
Formular for mechanical advantage is length of the slope divided by the height of the inclined plane.[tex]1.85 \div 0.72 = 2.56[/tex]Approximately 2.6What is the force (in Newtons, 1 Newton = 1Kgm/s2) required to accelerate a 1500 Kg car to 3 m/s2?
Answer:
F=4500N
Explanation:
F=m×g
F=1500kg×3m/s²
F=4500N
Answer:
F=4500N
Explanation:
F=m×g
F=1500kg×3m/s²
F=4500N
how is red shift evidence of the big bang
it implies our universe is expanding
it implies our universe is collapsing
it implies our universe is standing still
Answer:
it implies our universe is expanding
Can cause a stationary object to start moving or moving object to change its speed or direction or both
Answer:
Force
Explanation:
Only a force can cause a stationary object to move or a moving object to change its speed or direction.
Number 1a and b and number 2(everything)
Answer:
Explanation:
The density of a substance is the ratio of its mass to its volume. Its unit of measurement is kg[tex]m^{-3}[/tex].
i.e density, ρ = [tex]\frac{mass}{volume}[/tex]
1a. To determine the density of the acetic acid, Rachael needs to know the mass and volume of the acid.
i. Measure the mass of the given beaker using the mass balance.
ii. Transfer the acetic acid into the beaker, and measure the new mass using the mass balance.
iii. Subtract the mass of the beaker from the new mass to determine the mass of the acetic acid.
iv. Measure the volume of the acid on the scale of the beaker.
v. Divide the value of the mass by its volume to determine its density of the acetic acid.
b. Given that the density is 1.05 g/[tex]cm^{3}[/tex], and volume is 200 [tex]cm^{3}[/tex].
Then,
density = [tex]\frac{mass}{volume}[/tex]
1.05 = [tex]\frac{mass}{200}[/tex]
mass = 1.05 x 200
= 210 g
mass = 210 g
2. Length of titanium = 0.40 m
Area of titanium = 0.05 [tex]m^{2}[/tex]
mass = 90.0 kg
density = [tex]\frac{mass}{volume}[/tex]
But,
volume = area x length
= 0.05 x 0.4
= 0.02 [tex]m^{3}[/tex]
density of titanium = [tex]\frac{90}{0.02}[/tex]
= 4500 kg[tex]m^{-3}[/tex]
identical spheres are dropped from a height of 100 m above the surfaces of Planet X and Planet Y. The speed of the spheres as a function of time is recorded for each planet in the graph
above. Which planet exerts the greater force of gravity on the sphere, and what evidence supports this conclusion?
A Planet X because its line has the greater area under it.
Planet X, because its line has the greater slope
Planet Y. because it falls for the smaller amount of time
Planet Y because the object's final speed is greater
Answer:
B. Planet X, because its line has the greater slope.
Explanation:
In a speed graph, acceleration is slope. A greater slope means a greater acceleration. According to Newton's 2nd law (F=mg), a greater acceleration means a greater force.
Planet X exerts the greater force of gravity on the sphere, because its line has the greater slope. Hence option B is correct.
What is Gravitational Force ?Gravitational force is force of attraction between two masses. Gravitational force(F) between two bodies is directly proportion to the product of masses(m₁,m₂) of two bodies and inversely proportional to square of distance(r) between them. mathematically it is written as,
F ∝ m₁.m₂
F ∝ 1/r²
F = G m₁,m₂÷r²
where G is gravitational constant, whose value is 6.6743 × 10⁻¹¹ m³ kg-1s⁻².
Force is expressed in Newton N in SI unit. its dimensions are [M¹L¹T⁻²].
This is analogous with coulomb's law which gives force between two charges.
if a planet has greater gravitational force(force of gravity), then body falls with greater speed as compare to other planet which is having less force of gravity. we can see in case of planet X there is greater speed as compare to plane Y in short time. Hence option B is correct.
To know more about Gravity :
https://brainly.com/question/31321801
#SPJ2.
help plz i need it in the next 30 mins
Answer:
i think it's d
Explanation:
Answer:
D
Explanation:
i feel like this one is it
A box of weighing 60N is placed on the ground. The bottom of the box measures 2m by 1m. What is the pressure on the ground? *
Answer:
pressure=force/area
p=60N/(2m×1m)
=35N/M
B. How does potential energy change when
mass is increased?
Answer:
with the increase in mass of the object , the force of gravitation increases that eventually increases the potential energy if the object is still fixed in its relative position with surrounding objects.
Explanation:
hopes this will help you
A runner starts from rest and accelerates at a rate of 1.5 m/s2 and covers 375 m. How long did it take the runner to cover this distance?
Answer:
it takes him 22.36 seconds to cover that distance
Explanation:
We can solve this problem using the kinematic equation for uniformly accelerated motion:
[tex]x_f-x_i=v_0*t\,+\,\frac{1}{2} a\,*\,t^2[/tex]
which replacing the values given for our case becomes:
[tex]375=0*t\,+\,\frac{1}{2} (1.5)\,t^2\\375=\frac{1}{2} (1.5)\,t^2[/tex]
and which solving for t gives:
[tex]375=\frac{1}{2} (1.5)\,t^2\\t^2=2*375/1.5\\t^2=500\\t=\sqrt{500} \\t \approx 22.36\,\,sec[/tex]
A ball weighing 60 N is swinging like a pendulum at the end of a 6.0 m rope. As the ball swings through its lowest point, its speed is measured at 5.0 m/s. What is the tension in the rope at this point?
A. 58.6 N
B. 85.4 N
C. 90.2 N
D. 97.3 N
Answer:
85.4 N
Explanation:
Weight of the ball, W = 60 N
W = mg, m is mass
m = W/g
m = 60/9.8 = 6.12 kg
Length of a rope, r = 6 m
Speed, v = 5 m/s
We need to find the tension in the rope at this point. Tension is equal to the centripetal force It is given by :
[tex]F=\dfrac{mv^2}{r}+mg\\\\F=\dfrac{6.12\times (5)^2}{6}+60\\\\=85.5\ N[/tex]
So, the correct option is (b) " 85.4 N".
A little girl is walking, swinging her arms through a 20° angle every 0.25 s. The length of each arm is 30 cm. Assuming that the arms move with constant speed during each swing, find the force that the blood vessel in her arm would exert on a 1-gram drop of blood from the end of the arm if her arm were not swinging.
Answer:
The force will be "[tex]9.8\times 10^{-3} \ N[/tex]".
Explanation:
The given values are:
Mass,
m = 1 gram
Angle,
Ф = 20°
As we know,
⇒ [tex]F=mg[/tex]
On substituting the given values in the above expression, we get
⇒ [tex]=(1.0\times 10^{-3})(9.8)[/tex]
⇒ [tex]=9.8\times 10^{-3} \ N[/tex]
mester Exam 1 11 of 35
A car has an oil drip. As the car moves, it drips oil at a regular rate, leaving a trail of spots on the road. Which diagram shows the spots
of car that is continuously slowing down?
a 9.0-kg dog runs at 4.0 m/s and jumps onto a stationary skateboard the mas of the skateboard is 1.0 m/s what speed is the speed of the skating dog?
Answer:
1.3
Explanation:
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g During the contraction of the heart, 65 cm3 blood is ejected from the left ventricle into the aorta with a velocity of approximately 98 cm/s. The blood volume traverses the aortic arch, exiting with the same speed but opposite direction. Assume the mass density of the blood is 1060 kg/m3 blood, the aortic arch remains stationary, and that the heart rate is 61 bpm. What is the average force exerted by the blood on the wall of the aorta.
Answer:
The force is [tex]F = 0.1441 \ N[/tex]
Explanation:
From the question we are told that
The volume of blood ejected is [tex]V_b = 65cm^3 = 65*10^{-6} \ m^3[/tex]
The velocity of the ejected blood is [tex]v = 98 cm/ s = 0.98 \ m/s[/tex]
The mass density of blood is [tex]\rho = 1060 \ kg/m^3[/tex]
The heart rate is [tex]R = 61 bpm(beats \ per \ miunite) = \frac{61}{60} = 1.0667\ bps[/tex]
Generally the average force exerted is mathematically represented as
[tex]F = 2 * \rho * V_b * R * v[/tex]
=> [tex]F = 2 * 1060 * (65*10^{-6}) *1.0667 * 0.98[/tex]
=> [tex]F = 0.1441 \ N[/tex]
The wave produced by a piano's middle C has a frequency of 440 Hz
and a wavespeed of 344 m/s. What is its wavelength?
Answer:
0.78 m
Explanation:
I just did a hw question for this its just 344 divided by 440
Consider a star that is a sphere with a radius of 6.32 108 m and an average surface temperature of 5350 K. Determine the amount by which the star's thermal radiation increases the entropy of the entire universe each second. Assume that the star is a perfect blackbody, and that the average temperature of the rest of the universe is 2.73 K. Do not consider the thermal radiation absorbed by the star from the rest of the universe. J/K
Answer:
The value is [tex]\Delta s = 8.537 *10^{25 } \ J/K[/tex]
Explanation:
From the we are told that
The radius of the sphere is [tex]r = 6.32 *10^{8} \ m[/tex]
The temperature is [tex]T_x = 5350 \ K[/tex]
The average temperature of the rest of the universe is [tex]T_r = 2.73 \ K[/tex]
Generally the change in entropy of the entire universe per second is mathematically represented as
[tex]\Delta s = s_r - s_x[/tex]
Here [tex]s_r[/tex] is the entropy of the rest of the universe which is mathematically represented as
[tex]s_r = \frac{Q}{T_r}[/tex]
Here Q is the quantity of heat radiated by the star which is mathematically represented as
[tex]Q = 4 \pi * r^2 * \sigma * T^4_x[/tex]
Here [tex]\sigma[/tex] is the Stefan-Boltzmann constant with value
[tex]\sigma = 5.67 * 10^{-8 }W\cdot m^{-2} \cdot K^{-4}.[/tex]
=> [tex]Q = 4 \pi * (6.32*10^{8})^2 * 5.67 * 10^{-8 } * 5350 ^4[/tex]
=> [tex]Q = 2.332 *10^{26} \ J[/tex]
So
[tex]s_r = \frac{2.332 *10^{26}}{2.73}[/tex]
=> [tex]s_r = 8.5415 *10^{25}\ J/K[/tex]
Here [tex]s_x[/tex] is the entropy of the rest of the universe which is mathematically represented as
[tex]s_x = \frac{Q}{T_x}[/tex]
=> [tex]s_x = \frac{2.332 *10^{26} }{5350}[/tex]
=> [tex]s_x = 4.359 *10^{22} \ J/K[/tex]
So
[tex]\Delta s = 8.5415 *10^{25} - 4.359 *10^{22}[/tex]
=> [tex]\Delta s = 8.537 *10^{25 } \ J/K[/tex]
This question involves the concepts of entropy and the thermal radiation
The entropy of the entire universe is increased by "8.41 x 10²⁵ J/k
".
The increase in entropy is given as follows:
[tex]\Delta s = s-s_T[/tex]
where,
Δs = increase in entropy = ?
σ = Stefan-Boltzman's constant = 5.67 x 10⁻⁸ W/m².k⁴
A = surface area = 4πr² = 4π(6.32 x 10⁸ m)² = 5.01 x 10¹⁸ m²
Tr = Absolute temperature of the star = 5350 K
T = absolute temperature of the rest of the universe = 2.73 k
Q = thermal radiation energy
Q = [tex]\sigma A T_r^4=(5.67\ x\ ^{-8}\ W/m^2.k^4)(5.01\ x\ ^{18}\ m^2)(5350\ k)^4=2.3\ x\ 10^{26}\ J[/tex]
s = entropy of the universe = [tex]\frac{Q}{T}=\frac{2.3\ x\ 10^{26}\ J}{2.73 k}=8.42\ x\ 10^{25}\ J/k[/tex]
[tex]s_T[/tex] = entropy of the star = [tex]\frac{Q}{T_r}=\frac{2.3\ x\ 10^{26}\ J}{5350\ k}=4.3\ x\ 10^{22}\ J/k[/tex]
Therefore,
Δs = 8.42 x 10²⁵ J/k - 4.3 x 10²² J/k
Δs = 8.41 x 10²⁵ J/k
Learn more about entropy here:
https://brainly.com/question/13146879?referrer=searchResults
A fruit bat falls from the roof of a cave. We know that her potential energy was
600 J, and that the roof of the cave was 12.8 meters high. What is her velocity
when she hits the ground?
Answer:
v = 15.65 m/s
Explanation:
We use conservation of mechanical energy between initial (i) and final (f) states:
Pi + KEi = Pf + KEf
At the top of the cave at the instant the bat starts to fall, there is only potential energy since the bat's velocity is zero.
Pi = m g h = 600 J
and the KEi = 0 J (no velocity)
Knowing the height of the cave's roof (12.8 m) , we can find the mass of the bat:
m = 600 J / (g 12.5) = 4.9 kg
Using conservation of mechanical energy, the final state is:
Pf + KEf = 600 J
with Pf = 0 (just touching the ground)
KEf= 1/2 4.9 (v^2)
and we solve for the velocity:
600 J = 0 + 1/2 4.9 (v^2)
v^2 = 600 * 2 / 4.9 = 244.9
v = 15.65 m/s
As a block of mass 42 kilograms drops from the edge of a 40-meter-high cliff it experiences a loss of energy due to air resistance of 81 J. At what speed will the rock hit the ground?
Answer:
The block hits the ground at 27.9 m/s
Explanation:
Gravitational Potential Energy (GPE)
It's the energy stored in an object because of its height in a gravitational field.
It can be calculated with the equation:
U=m.g.h
Where m is the mass of the object, h is the height with respect to a fixed reference, and g is the acceleration of gravity or [tex]9.8 m/s^2[/tex].
When the block is at the edge of the cliff it has potential energy that can be transformed into any other type of energy as it starts falling to the ground.
The GPE of the block of mass m=42 Kg at h=40 m is:
U = 42*9.8*40
U = 16,464 J
The block loses 81 J due to air resistance, thus the energy stored when it hits the ground is 16,464 J - 81 J = 16,383 J.
This energy is stored as kinetic energy, whose formula is:
[tex]\displaystyle K=\frac{1}{2}mv^2[/tex]
Solving for v:
[tex]\displaystyle v=\sqrt{\frac{2K}{m}}[/tex]
[tex]\displaystyle v=\sqrt{\frac{2*16,383 }{42}}[/tex]
[tex]v=\sqrt{780.143}[/tex]
v = 27.9 m/s
The block hits the ground at 27.9 m/s
Katniss everdeen applies 20 n of force back on her bow what happens to the arrow when she lets go?
Define a rotation of the earth answer fast
Answer:
here u go
Explanation:
Earth's rotation is the rotation of planet Earth around its own axis. Earth rotates eastward, in prograde motion. As viewed from the north pole star Polaris, Earth turns counterclockwise.
PLEASE HELP! what kind of electricity does electrical heat burners make
Answer:
Electrical to Thermal
ASAP PLS HELP
What is chemical potential energy?
Answer:
chemical potential of a species is energy that can be absorbed or released due to a change of the particle number of the given species, e.g. in a chemical reaction or phase transition.
Explanation:
When 26400j of energy is supplied to a 2.0kg bloom of aluminum it temperature rise from 20oc to 35oc.The block is well so there is no energy lost to sorround determine the specific heat capacity of aluminum
Answer:
880J/kelvin
Explanation:
Q =MC ×change in t
c =C/m
C=Q/change in t
c= Q/ m× change in t
c = 26400 / 2.0 × 15
c = 880 J/kelvin