Give three examples of the importance of gravity to humans?
A cart moving at 4.0 m/s has 44 J of kinetic energy. What is the cart's mass?
[tex]ke = \frac{1}{2} m {v}^{2} [/tex]
[tex]44 = \frac{m {4}^{2} }{2} \\ \frac{88}{16} = m \\ 5.5 = m[/tex]
If the temperature (at constant volume) of an ideal gas with 20 K is increased to 60 K, the pressure will be:
increased to 3P
increased to 40P
decreased by 3P
decreased by 40P
Answer:
it will obviously be decreased by 40p
A ray of light passes from air into cubic zirconia at an angle of 56.0° to the normal. The angle of
refraction is 22.00°.
What is the index of refraction of cubic zirconia?
Answer:
η = 2.2
Explanation:
The index of refraction is given by the following formula:
[tex]\eta = \frac{Sin\ \theta_i}{Sin\ \theta r}[/tex]
where,
η = index of refraction of cubic zirconia = ?
[tex]\theta_i[/tex] = angle of incidence = 56°
[tex]\theta_r[/tex] = angle of refraction = 22°
Therefore,
[tex]\eta = \frac{Sin\ 56^o}{Sin\ 22^o}\\\\\eta = \frac{0.829}{0.375}[/tex]
η = 2.2
Which two parts do the capillaries surround?
A. small intestines and heart
B. heart and lungs
C. alveoli and small intestines
Answer:
do we have to choose 2 answers here?
Answer:
most probably it's C
Explanation:
alveoli is surrounded by capillaries and whit that option small intestines is also there
When an object absorbs light energy, it reflects
A. all of the colors
B. none of the colors
C. only the colors you see
When an object absorbs light energy, it reflects none of the colors. The correct option is B.
What is reflection?The change in direction of a wavefront at an interface between two different media so that the wavefront returns to the medium from which it originated is referred to as reflection. Reflection of light, sound, and water waves are common examples.
Objects appear different colors because they absorb certain colors (wavelengths) while reflecting or transmitting others. The wavelengths that are reflected or transmitted are what we see as colors.
If photon energy is absorbed, the energy from the photon is typically manifested as heating the matter.
Light absorption causes an object to become dark or opaque to the wavelengths or colors of the incoming wave: Wood is impervious to visible light.
Thus, the correct option is B.
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What are successfulness of the Competition policy in South Africa?
Answer:
The product choices along with its competitive prices were provided to the consumers. Practices such as horizontal collusion and resale price maintenance was declared unlawful in 1984. Prevention of monopoly growth was the aim of the competition policy act.
Explanation:
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A student is building a model of a lens that will spread light over the biggest space. Which best describes the type of model the student should make?
O A The student should make a convex lens model because it directs light away from the center of the lens.
OB. The student should make a concave lens model because it breaks light down into bands of color
c. The student should make a concave lens model because it directs light away from the center of the lens
D. The student should make a convex lens model because it breaks light down into bands of color.
Answer:
C. The student should make a concave lens model because it directs light away from the center of the lens
Explanation:
The student should make a concave lens model because it directs light away from the center of the lens.
What is Concave lens?A lens that has at least one inward-curving surface is said to be concave. Since it is a divergent lens, light rays that have been bent by it are dispersed. Short-sightedness is treated by concave lenses, which are thinner in the center than the borders (myopia).
The earliest known usage of a corrective lens is mentioned in Pliny the Elder's writings (23–79). Pliny claims that Emperor Nero used an emerald, perhaps concave formed to adjust for myopia, to watch gladiatorial matches.
After passing through the lens, light beams appear to originate from a spot known as the primary focus.
Therefore, The student should make a concave lens model because it directs light away from the center of the lens.
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A projectile is launched from the ground with an initial velocity of 12m/s at an angle of 30° above the horizontal. The projectile lands on a hill 7.5m away. The height at which the projectile lands is most nearly
Answer:
[tex]1.78\:\mathrm{m}[/tex]
Explanation:
Kinematics equations used:
[tex]v_f=v_i+at,\\\\\Delta y = v_it+\frac{1}{2}at^2,\\\\v_f^2=v_i^2+2a\Delta x[/tex]
Other equations used:
[tex]\Delta x =v_i\cdot t,\\\text{-basic trigonometry for right triangles},\\\text{-application of physics concepts}[/tex]
By finding the horizontal component of the projectile's initial launch, we can find how long it will take for the projectile to reach the hill.
Since the projectile is launched at 12 m/s 30 degrees above the horizontal, we can use basic trig for a right triangle to find the horizontal component of the launch:
[tex]\cos 30^{\circ}=\frac{x}{12},\\x=12\cos 30^{\circ}\approx 10.3923048454\:\text{m/s}[/tex]
Now we can use [tex]\Delta x =v_x\cdot t[/tex] to find the time it will take to reach the hill:
[tex]7.5=10.3923048454\cdot t,\\t=\frac{7.5}{10.3923048454}\approx 0.72168783648\:\text{s}[/tex]
To find the total flight time the projectile would take if it were to land back to the same height it started out with, we can use the following kinematics equation:
[tex]v_f=v_i+at[/tex]
We'll use basic trig for a right triangle again to find the vertical component of the velocity at launch:
[tex]\sin 30^{\circ}=\frac{y}{12},\\y=12\sin 30^{\circ}=6\:\text{m/s}[/tex]. (recall [tex]\sin 30^{\circ}=\frac{1}{2}[/tex])
Now plugging this value in:
*Note: the projectile will hit the ground with a vertical velocity equal in magnitude but opposite in direction than the projectile's initial vertical velocity at launch
[tex]-6=6+(-9.8\cdot t),\\t=\frac{-12}{-9.8},\\t=1.22448979592\:\text{s}[/tex]
^This is the total flight time the projectile would take if it were to land back to the same height it started with. Since acceleration is constant, we can divide this time by two to find the time it would take to reach maximum height.
[tex]1.22448979592\div 2=0.61224489795\:\text{s}[/tex]
Thus, it will take [tex]0.61224489795\:\text{s}[/tex] to reach maximum height, meaning that it will take [tex]0.72168783648 - 0.61224489795=0.10944293853\:\text{s}[/tex] to land on the hill after reaching maximum height. Now that we've found this, we can use the following kinematics equation to find the vertical displacement from the projectile's max height to the hill:
[tex]\Delta y =v_it+\frac{1}{2}at^2[/tex]
At maximum height, the projectile's vertical velocity will be zero. Therefore, [tex]v_i=0[/tex] and we have:
[tex]\Delta y =\frac{1}{2}at^2[/tex]
Plugging in values , we have:
[tex]\Delta y =\frac{1}{2}\cdot 9.8\cdot 0.10944293853^2=0.05869100829\:\text{m}[/tex]
This means that the hill is [tex]0.05869100829\:\text{m}[/tex] lower than the max. height the object will reach.
To find the height of the hill from the ground, we will use the following kinematics equation:
[tex]v_f^2=v_i^2+2a\Delta x,\\-6^2=0+2\cdot-9.8\cdot\Delta x,\\36=-19.6\Delta x,\\\Delta x =\frac{36}{-19.6},\\\Delta x =-1.83673469388\:\text{m}[/tex]
Therefore, the max. height that the object will reach is [tex]1.83673469388\:\text{meters}[/tex].
Thus, the hill's height is [tex]1.83673469388-0.05869100829=1.77804368559\:\text{m}\approx\boxed{1.78\:\mathrm{m}}[/tex].
An astronaut in space cannot use a conventional means, such as a scale or balance, to determine the mass of an object. But she does have devices to measure distance and time accurately. She knows her own mass is 78.4 kg, but she is unsure of the mass of a large gas canister in the airless rocket. When this canister is approaching her at 3.50 m/s, she pushes against it, which slows it down to 1.20 m/s (but does not reverse it) and gives her a speed of 2.40 m/s. What is the mass of this canister
Answer:
81.81 kg
Explanation:
[tex]m_1[/tex] = Mass of person = 78.4 kg
[tex]m_2[/tex] = Mass of canister
[tex]u_1[/tex] = Initial velocity of person = 0
[tex]u_2[/tex] = Initial velocity of canister = 3.5 m/s
[tex]v_1[/tex] = Final velocity of person = 2.4 m/s
[tex]v_2[/tex] = Final velocity of canister = 1.2 m/s
The momentum balance in the system is given by
[tex]m_1u_1+m_2u_2=m_1v_1+m_2v_2\\\Rightarrow 78.4\times 0+m_2\times 3.5=78.4\times 2.4+m_2\times 1.2\\\Rightarrow m_2=\dfrac{78.4\times 2.4}{3.5-1.2}\\\Rightarrow m_2=81.81\ \text{kg}[/tex]
Mass of the canister is 81.81 kg.
Using the diagram above, the coefficient of kinetic friction for copper is ____ (Your answer should be given to the nearest thousandths.)
This coefficient _____ applies to all similar copper surfaces.
Answer:
μ= 0.0375, kinetic
Explanation:
For this exercise we set a reference system with the x axis parallel to the chord
Y axis
N - W = 0
N = W
X axis
T - fr = 0
the expression for the friction force is
fr = μ N
we substitute
T - μ W = 0
μ = T / W
we calculate
μ = 1.5 / 40
μ= 0.0375
coefficient of kinetic friction
Ganymede, the largest of Jupiter’s moons,
is also the largest satellite in the solar system. Find the acceleration of
gravity on Ganymede if a simple pendulum with a length of 1.00 m has a period
of 10.5 s
Answer:hereeee for pointssss only
Explanation:
The acceleration of gravity on Ganymede will be [tex]g=0.35\ \frac{m}{s^2}[/tex]
What will be the acceleration of gravity on Ganymede?It is given that for a simple pendulum on Ganymede
Lenth= 1.00 m
the time period T= 10.5 sec
The formula for a time period of simple pendulum will be
[tex]T=2\pi\sqrt{\dfrac{l}{g} }[/tex]
By rearranging the formula
[tex]g=l\times (\dfrac{2\pi}{T} )^2[/tex]
[tex]g=1\times (\dfrac{2\pi}{10.5} )^2=0.3577\frac{m}{s^2}[/tex]
[tex]g=0.3577\ \frac{m}{s^2}[/tex]
Thus the acceleration of gravity on Ganymede will be [tex]g=0.35\ \frac{m}{s^2}[/tex]
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Why unit of pascal is called derived unit?
Answer:
This is because it is derived from newtons and metres as shown in the expression;
Explanation:
[tex]pressure = \frac{force}{area} \\ P= \frac{F}{A} \\ P= \frac{newtons}{ {m}^{2} } \\ = pascals[/tex]
Answer:
Unit of pascal is called derived unit because it involves three fundamental units i.e.meter,kg,and second.
Explanation:
formula of pascal=kg/m/s^2
The different between capactance wnd capacitor
Answer:
The parallel plate capacitor is the simplest form of capacitor. ... The property of a capacitor to store charge on its plates in the form of an electrostatic field is called the Capacitance of the capacitor. Not only that, but capacitance is also the property of a capacitor which resists the change of voltage across it.
Explanation:
credits :- adultsscience
Explanation:
Capacitance exists wherever conductive material is separated by insulating material.
Capacitive structures have the ability to store energy as an electric field;
when a capacitive structure has been designed as an electrical component that has a specified amount of capacitance, it is called a capacitor.
Capacitance symbol is C
you can get a meter for Capacitance
Capacitance formula is C = ε(A/d) where ε represents the absolute permittivity of the dielectric material being used.
simple piece of wire has very low capacitance
What voltage is required to move 2A through 10 Ω?
Answer:
20V
Explanation:
Given: I=2A
R=10Ω
Solution: V = I × R
=(2A)×(10ohm)
=20V
A car accelerates at a rate of 13m/s^2[S]. If the car's initial velocity is 120km/h[N]. What will be its final velocity in m/s, after 2 seconds.
Answer:
the final velocity of the car is 59.33 m/s [N]
Explanation:
Given;
acceleration of the car, a = 13 m/s²
initial velocity of the car, u = 120 km/h = 33.33 m/s
duration of the car motion, t = 2 s
The final velocity of the car in the same direction is calculated as follows;
v = u + at
where;
v is the final velocity of the car
v = 33.33 + 13 x 2
v = 59.33 m/s [N]
Therefore, the final velocity of the car is 59.33 m/s [N]
A baseball is thrown at a 22.5° angle and an initial velocity of 65 m/s. What will be its horizontal
and vertical velocity?*
Answer:
Horizontal
Explanation:
It is going more sideways than upwards
How does the motion of the atoms in the spoon change when the spoon is placed in the hot coffee?
А
The atoms vibrate faster due to the conduction of heat through atoms in the spoon.
B
The atoms vibrate slower due to the conduction of heat through atoms in the spoon
С
The atoms move closer toward each other due to the radiation of heat through atoms in the spoon.
D
The atoms move away from each other due to the convection of heat through atoms in the spoon.
Answer:
A.The atoms vibrate faster due to the conduction of heat through atoms in the spoon.
A bird is standing on an electric transmission line carrying a large amount of current. Find the power dissipated by the bird If the
current it experiences is 1.35^-10 A which results in a potential difference of .0054V.
Side Note:
(I know the answer is 7.3 x 10^-11 W, I just don’t know how to get it)
P = 7.3 × 10^-13 Watt
Explanation:
First of all, are you sure that what you have is the right answer?
Anyway, the definition of power dissipated is given by
P = I^2×R
where I is the current and R is the resistance. But we also know from Ohm's law that
V = IR
so we can rewrite the equation for power P as
P = I^2R = I(IR) = VI
= (0.0054 volt)(1.35 × 10^-10 A)
= 7.3 × 10^-13 Watt
All eukaryotic cells have mitochondria, but only the cells of photosynthetic organisms have chloroplasts. Explain how what takes place in chloroplasts differs from what takes place in mitochondria (singular = mitochondria).
Answer:
Explanation:
In the chloroplast, photosynthesis occur. The chloroplast capture light energy from the sun and use it with carbondioxide and water to produce glucose and oxygen. Chloroplasts is found in plant cells only
But mitochondria is refer as the power House of the cell. It's break down fuel molecules and produce energy in cellular respiration. Mitochondria is found in both plant and animal cell.
PLEASE ANSWER ASAP, WILL MARK BRAINLIEST***
A traveler at Newark airport pulls his 294N suitcase with constant velocity to the check-in counter applying a force of 159N at an angle of 37 degrees with the horizontal. Calculate the Normal force, frictional force and the coefficient of friction between the suitcase and the airport floor.
Answer:
N = 198.3 N, fr = 126.98 N and μ = 0.64
Explanation:
For this exercise we must use the translational equilibrium condition.
Let's set a reference system with the x-axis horizontally and the y-axis vertical. Let's use trigonometry to decompose the applied force
cos θ = Fₓ / F
sin θ = F_y / F
Fₓ = F cos θ
F_y = F sin θ
Fₓ = 159 cos 37 = 126.98 N
F_y = 159 sin 37 = 95.69 N
Y axis
N + F_y - W = 0
N = W - F_y
N = 294 - 95.69
N = 198.3 N
X axis
Fₓ -fr = 0
Fₓ = fr
fr = 126.98 N
the expression for the friction force is
fr = μ N
μ = fr / N
μ = 126.98 / 198.3
μ = 0.64
5 points
The figure below shows two people ice-skating. Person A collides with
person B. After the collision they move together with the same velocity.
Calculate the mass, m, of person B.
Before collision
After collision
Person A
mass = 60 kg
Person B
mass, m
Person A and person B
moving off together
Speed of
Person A -
5.5 m/s
Speed of
Person B -
2.0 m/s
Speed of Person A and
Person B = 4.0 m/s
mB = 45 kg
Explanation:
Using conservation of linear momentum,
mAvA + mbvB = (mA + mB)v
(60 kg)(5.5 m/s) + (2.0 m/s)mB = (60 kg + mB)(4.0 m/s)
(330) + 2mB = 240 + 4mB
2mB = 90
mB = 45 kg
Of all of the structures in a cell, which actually contains the cell's DNA? A. Mitochondria B. Cell membrane C. Nucleus D. Cytoplasm
Answer:
C. Nucleus
Explanation:
The nucleus, formed by a nuclear membrane around a fluid nucleoplasm, is the control center of the cell. Threads of chromatin in the nucleus contain deoxyribonucleic acid (DNA), the genetic material of the cell.
have a good day and here’s a funny comic just for fun! :)
Atoms in Group 18 elements are inert (chemically unreactive) because ___________________________. A they combined to form molecules. B they have no valence electrons. C they have filled inner energy levels. D they have a full valence shell.
When you say full valence shell, are you talking about a valence electron shell?
I am learning about atoms and i know a little bit
Atoms in Group 18 elements are inert (chemically unreactive) because they have no valance electrons. The correct option is B.
What is valency?In chemistry, an element's valence or valency is the measure of its ability to combine with other atoms to form chemical compounds or molecules.
The number of atoms of one element combined with one atom of another element to form a molecule is referred to as its valency.
Valency is also referred to as molecular weight. Valency is a measure of an atom's combining power. The number of electrons in an element's outermost shell determines its valency.
Because of their full valence shells, noble gases are unreactive. They do not easily gain or lose electrons because they are already in the most stable electronic configuration.
Thus, the correct option is B.
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What is the new speed for an 10 kg object after 16500 N was applied to it for 2 seconds?
Answer: 3300 m/s
F = ma; units: N = kg(m/s/s); where F and a are both vectors, while m, t, and v (speed) are scalars
We are given the mass, force, and the time; however, speed is our unknown.
[F = 16500 N] [m = 10 kg] [t = 2 s] [v = unknown]
What we can do is use kinematics in order to relate v and t with F and m:
For example, we can use V = V₀ + at
Since F = ma can equal a = F/m, we can replace the a variable within the kinematics equation with F/m, so that:
V = V₀ + at
V = V₀ + (F/m)t
In this problem, we can assume the initial value V to equal 0, giving us:
V = (F/m)t
Plugging in the quantities we get:
V = [tex]\frac{16500 N}{10kg}[/tex]· 2s
V = 3300 m/s
To further check whether this is the right manipulated equation to use, we can use dimensional anaylsis to determine that:
V = [tex]\frac{kg(m/s/s) }{kg}[/tex]· s
V = m/s
I hope this helped!
A lamp is connected to the power supply.
The lamp requires an input potential difference of 5.0V
The alternator generates a potential difference of 1.5V
The primary coil of the transformer has 150 turns.
Calculate the number of turns needed on the secondary coil
Number of turns on the secondary coil = ?
Answer:
There are 45 turns in the secondary coil.
Explanation:
Given that,
Input potential of the lamp, [tex]V_{in}=5\ V[/tex]
The output potential of the lamp, [tex]V_{out}=1.5\ V[/tex]
Number of turns in primary coil, [tex]N_P=150[/tex]
We need to find the number of turns needed on the secondary coil. We know that the ratio for a transformer is as follows :
[tex]\dfrac{V_{out}}{V_{in}}=\dfrac{N_s}{N_P}\\\\N_s=\dfrac{V_{out}N_P}{V_{in}}\\\\N_s=\dfrac{1.5\times 150}{5}\\\\N_s=45\[/tex]
So, there are 45 turns in the secondary coil.
When a wave passes from a less dense medium to a denser one, most of the
wave energy is
A. reflected.
B. diffracted.
C. absorbed.
D. refracted.
Answer:
D. Refracted
Explanation:
At the point when light passes from a less thick to a more thick substance, (for instance passing from air into water), the light is refracted (or bowed) towards the ordinary. The bowing happens on the grounds that light voyages all the more gradually in a denser medium. The answer is D, refracted.
Question 3.Two forces are acting on a 30-kg object, 200 N up and 300 N
down. What is the magnitude and direction of its acceleration?
A. It is 100 m/s2 upward,
B. It is 100 m/s2 downward.
C. It is 3 m/s2 upward.
D. It is 3 m/s2 downward.
Answer:
It is 3 m/s² downward.
Explanation:
The mass of an object, m = 30 kg
Upward force, F = 200 N
Downward force, F' = -300 N
We need to find the magnitude and direction of its acceleration.
Net force = F+F'
= 200+(-300)
= -100 N
We know that,
Force, F = ma, a is acceleration of the object
[tex]a=\dfrac{F}{m}\\\\a=\dfrac{-100}{30}\\\\a=-3.33\ m/s^2\approx -3\ m/s^2[/tex]
Hence, the acceleration is -3 m/s² and it is acting in the downward direction.
an optician uses a plane mirror to help him. suppse a patient sits in a chair 2.5m away from him. He views the image of a chart which faces the mirror and is located 30m behindd him. how far is the chart as viewed by his eyes
Answer:
I think 75 m
Explanation:
tell if it was correct