35 POINTSS!!! PLSSSS HELLPPP!!!
Work is the transfer of power from one object to another.
Please select the best answer from the choices provided
T
F
Answer:
T
beacuse:
Energy can be transferred from one object to another by doing work. ... When work is done, energy is transferred from the agent to the object, which results in a change in the object's motion (more specifically, a change in the object's kinetic energy).
Determine a formula for the maximum height h that a rocket will reach if launched vertically from the Earth's surface with speed v0(v < vesc). Express in terms of v0, rE, ME, and G.
Initially, the energies are:
[tex]U_{i}=-\frac{G M_{\varepsilon} m}{r_{e}} \\ =K_{i}=\frac{1}{2} m v_{0}^{2}[/tex]
At final point, the energies are:
[tex]U_{f}=-\frac{G M_{\varepsilon} m}{r_{e}+h} \\ K_{f}=\frac{1}{2} m(0)^{2}=0[/tex]
Using conservation law of energy,
[tex]-\frac{G M_{e} m}{r_{e}}+\frac{1}{2} m v_{0}^{2} &=-\frac{G M_{e} m}{r_{\varepsilon}+h} \\ -\frac{G M_{e}}{r_{e}}+\frac{v_{0}^{2}}{2} &=-\frac{G M_{e}}{r_{e}+h} \\ \frac{-2 G M_{e}+r_{e} v_{0}^{2}}{2 r_{e}} &=-\frac{G M_{e}}{r_{e}+h} \\ \frac{r_{e}+h}{G M_{e}} &=\frac{2 r_{e}}{2 G M_{e}-r_{e} v_{0}^{2}}[/tex]
The equation is further simplified as:
[tex]r_{e}+h &=\left(\frac{2 r_{e}}{2 G M_{e}-r_{e} v_{0}^{2}}\right) G M_{e} \\ h &=\frac{2 r_{e} G M_{e}}{2 G M_{e}-r_{e} v_{0}^{2}}-r_{e} \\ &=\frac{2 r_{e} G M_{e}-2 r_{e} G M_{e}+r_{e}^{2} v_{0}^{2}}{2 G M_{e}-r_{e} v_{0}^{2}} \\ & h=\frac{r_{e}^{2} v_{0}^{2}}{2 G M_{e}-r_{e} v_{0}^{2}}[/tex]
Sometimes a person cannot clearly see objects close up or far away. To correct this type of vision, bifocals are often used. The top half of the lens is used to view distant objects and the bottom half of the lens is used to view objects close to the eye. Bifocal lenses are used to correct his vision. A diverging lens is used in the top part of the lens to allow the person to clearly see distant objects.
1. What power lens (in diopters) should be used in the top half of the lens to allow her to clearly see distant objects?
2. What power lens (in diopters) should be used in the bottom half of the lens to allow him to clearly see objects 25 cm away?
Answer:
1) P₁ = -2 D, 2) P₂ = 6 D
Explanation:
for this exercise in geometric optics let's use the equation of the constructor
[tex]\frac{1}{f} = \frac{1}{p} + \frac{1}{q}[/tex]
where f is the focal length, p and q are the distance to the object and the image, respectively
1) to see a distant object it must be at infinity (p = ∞)
[tex]\frac{1}{f_1} = \frac{1}{q}[/tex]
q = f₁
2) for an object located at p = 25 cm
[tex]\frac{1}{f_2} = \frac{1}{25} + \frac{1}{q}[/tex]
We can that in the two expressions we have the distance to the image, this is the distance where it can be seen clearly in general for a normal person is q = 50 cm
we substitute in the equations
1) f₁ = -50 cm
2)
[tex]\frac{1}{f_2} = \frac{1}{25} + \frac{1}{50}[/tex]
[tex]\frac{1}{f_2}[/tex] = 0.06
f₂ = 16.67 cm
the expression for the power of the lenses is
P = [tex]\frac{1}{f}[/tex]
where the focal length is in meters
1) P₁ = 1/0.50
P₁ = -2 D
2) P₂ = 1 /0.16667
P₂ = 6 D
Explain in your
own words how
you would find
the density of a
regular-shaped
object.
Answer:
Use a ruler to measure the length (l), width (w) and height (h) of the object.Place the object on the top pan balance and measure its mass.Calculate the volume of the cube using (l*w*h).Use the measurements to calculate the density of the object.We say that the mass comes to rest if, after a certain time, the position of the mass remains within an arbitrary small distance from the equilibrium position. Will the mass ever come to rest
Answer:
No, the mass will never come to rest
Explanation:
It is so because even at arbitrarily small distance it will experience some amount of force (irrespective of how small the value of force is).
This does not allow the mass to become stationary or in a equilibrium state as it is still subject to some amount of force.
Hence, the the mass will never come to rest
can someone help
pls !
A 1.1-kg object is suspended from a vertical spring whose spring constant is 120 N/m. (a) Find the amount by which the spring is stretched from its unstrained length. (b) The object is pulled straight down by an additional distance of 0.20 m and released from rest. Find the speed with which the object passes through its original position on the way up.
Answer:
e = 0.0898m
v = 2.07m/s
Explanation:
a) According to Hooke's law
F = ke
e is the extension
k is the spring constant
Since F = mg
mg = ke
e = mg/k
Substitute the given value
e = 1.1(9.8)/120
e = 10.78/120
e = 0.0898m
Hence it is stretched by 0.0898m from its unstrained length
2) Total Energy = PE+KE+Elastic potential
Total Energy = mgh +1/2mv²+1/2ke²
Substitute the given value
5.0= 1.1(9.8)(0.2)+1/2(1.1)v²+1/2(120)(0.0898)²
Solve for v
5.0 = 2.156+0.55v²+0.48338
5.0-2.156-0.48338= 0.55v²
2.36 =0.55v²
v² = 2.36/0.55
v² = 4.29
v ,= √4.29
v = 2.07m/s
Hence the required velocity is 9.28m/s
scholastic science world
CHECK FOR UNDERSTANDING: VIDEO GAME TYCOONS
What is the Lorentz force law used for? A. To find the voltage of a battery B. To find the magnitude of a magnetic force C. To find the velocity of an electromagnetic wave. D. To find the direction of a magnetic field
Answer:
B
Explanation:
The Lorentz force is the sum of the electric force and magnetic force.
F = qE + qvB
qE represents electric force and qvB represents magnetic force
HELP 30 POINTS
The picture above shows a cross section of the Earth’s interior including both oceanic crust and continental crust. Along the seafloor, there are mid–ocean ridges where magma rises to the surface and creates new crust. There are also areas where crust is recycled as oceanic crust goes below continental crust. What type of boundary would occur at a mid-ocean ridge?
Mid-ocean ridges happen along divergent plate boundaries, where new ocean floor is created as the Earth’s tectonic plates spread apart. As the plates separate, molten rock rises to the seafloor, producing large volcanic eruptions of basalt.
Instead of changing the focal length of the lens, the eyes of amphibians work in a different manner: a set of muscles changes the shape of the eye which increases the distance between the front of the eye and the retina. The world's largest frog, the Goliath frog of west Africa, has an eye with a maximum size similar to a human's: 2.5cm. However, unlike a human, where the focal length is also 2.5cm, the focal length of the Goliath frog's eye is 2.146 cm. What is the maximum distance this frog can see
Answer:
The answer is "15.56 cm".
Explanation:
[tex]v= 2.5 \ cm\\\\f= 2.154 \ cm[/tex]
Calculating object of length is x so:
[tex]u= -x[/tex]
Using formula:
[tex]\to \frac{1}{v}-\frac{1}{u}=\frac{1}{f}\\\\\to \frac{1}{2.5}-\frac{1}{-x}=\frac{1}{2.154}\\\\\to \frac{1}{x}=\frac{1}{2.154}-\frac{1}{2.5}\\\\\to \frac{1}{2.5}-\frac{1}{-x}=\frac{1}{2.154}\\\\\to x= 15.56 \ cm[/tex]
Which of the following is true of the deep
water layer of the ocean?
A. warmest and least dense of the ocean layers
B. experiences a rapid decrease in temperature
C. is warm in the summer and cold in the winter
D. cold all year round
A wave has a frequency of 2 Hz. Find its period
Protons, neutrons, electrons, and a nucleus are
Heat transfer in liquids or gases that happens due to currents of hot and cold is called
Entropy
Conduction
Convection
Radiation
Answer:
convection it's your answer plz make me brainy least
There is a bell at the top of a tower that is 45 m high. The bell weighs 190 kg. The bell has
energy. Calculate it
Answer: The bell has 8550 J energy.
given, There is a bell at the top of a tower that is 45 m high. The bell weighs 190 N
i.e., bell is located at the top of tower, h = 45m
weight of the bell, F = 190 N
workdone by the gravitational force = F.hcos180°
[ gravitational force (i.e., weight ) acting downward while body is located 45m above the ground. so, angle between force and h = 180° ]
workdone by the gravitational force = 190 × 45 × (-1)
= -8550 J
we know, potential energy = negative of workdone
= -(-8550 J) = 8550 J
Answer:
200,000J
Explanation:
KE= 0.5 x m x v^2
KE= 0.5x1000x20^2
KE= 0.5 x 1000 x 400
KE= 500 x 400
KE= 200,000
In many places on Earth, humans are responsible for the removal of grasses, shrubs, trees, and other plants with roots that hold soil in place. This activity is best described by which of the following? *
A) deforestation
B) urbanization
C) air pollution
D) rise in sea level
A phase change is when a substance changes from one state of mind to nother because of the adding or removal of thermal energy
True
False
Answer:
true it all changes
Explanation:
________________________
It takes 20 seconds to fill a two-liter bottle with water from your kitchen faucet. What is the mass flow rate from the faucet if water has a density of 1000 fraction numerator k g over denominator m cubed end fraction?
a. 0.1kg/sec.
b. 0.01kg/sec.
c. 1g/sec.
d. 1kg/sec.
Answer:
0.1 kg/s.
Explanation:
The density of water, d = 1000 kg/m³
Volume, V = 2 L
Time, t = 20 s
We need to find the mass flow rate from the faucet. We know that the density of an object is given by :
[tex]d=\dfrac{m}{V}\\\\m=d\times V\\\\\dfrac{m}{t}=\dfrac{dV}{t}\\\\\dfrac{m}{t}=\dfrac{1000\times 0.002}{20}\\\\=0.1\ kg/s[/tex]
So, the mass flow rate is equal to 0.1 kg/s.
In a movie production, a stunt person must leap from a balcony of one building to a balcony 3.0 m lower on another building. If the buildings are 2.0 m apart, what is the minimum horizontal velocity the stunt person must have to accomplish the jump? Assume no air resistance and that ay = −g = −9.81 m/s2 . (Ans. 2.6m/s) PLS SHOW WORK
This question involves the concept of semi-projectile motion. It can be solved using the equations of motion in the horizontal and the vertical motion.
The minimum horizontal velocity required is "2.6 m/s".
First, we will analyze the vertical motion of the stunt person. We will use the second equation of motion in the vertical direction to find the time interval for the motion.
[tex]h=v_it+\frac{1}{2}gt^2[/tex]
where,
h = height = 3 m
vi = initial vertical speed = 0 m/s
t = time interval = ?
g = acceleration due to gravity = 9.81 m/s²
therefore,
[tex]3\ m = (0\ m/s)(t) + \frac{1}{2}(9.81\ m/s^2)t^2\\\\t^2 = \frac{(3\ m)(2)}{9.81\ m/s^2}\\\\t = \sqrt{0.611\ s^2}[/tex]
t = 0.78 s
Now, we will analyze the horizontal motion. We assume no air resistance, so the horizontal motion will be uniform. Hence, using the equation of uniform motion here:
[tex]s = vt\\\\v = \frac{s}{t}[/tex]
where,
s = horizontal distance = 2 m
t =0.78 s
v = minimum horizontal velocity = ?
Therefore,
[tex]v = \frac{2\ m}{0.78\ s}[/tex]
v = 2.6 m/s
Learn more about equations of motion here:
brainly.com/question/20594939?referrer=searchResults
The attached picture shows the equations of motion in the horizontal and vertical directions.
Which of the following is NOT an example of Potential Energy? *
Chemical bonds
Gravitational energy
Electricity
Answer:
chemical bonds
Explanation:
because no energy is required
A 101 kg basketball player crouches down 0.380 m while waiting to jump. After exerting a force on the floor through this 0.380 m, his feet leave the floor and his center of gravity rises 0.920 m above its normal standing erect position. (a) Using energy considerations, calculate his velocity (in m/s) when he leaves the floor. m/s (b) What average force (in N) did he exert on the floor
Answer:
[tex]4.25\ \text{m/s}[/tex]
[tex]3391.22\ \text{N}[/tex]
Explanation:
y = Height of compression = 0.38 m
m = Mass of basketball player = 101 kg
h = Height of center of gravity after jump = 0.92 m
g = Acceleration due to gravity = [tex]9.81\ \text{m/s}^2[/tex]
Energy balance of the system is given by
[tex]mgh=\dfrac{1}{2}mv^2\\\Rightarrow v=\sqrt{2gh}\\\Rightarrow v=\sqrt{2\times 9.81\times 0.92}\\\Rightarrow v=4.25\ \text{m/s}[/tex]
The velocity of the player when he leaves the floor is [tex]4.25\ \text{m/s}[/tex]
[tex]Fy=mgy+\dfrac{1}{2}mv^2\\\Rightarrow F=\dfrac{mgy+\dfrac{1}{2}mv^2}{y}\\\Rightarrow F=\dfrac{101\times 9.81\times 0.38+\dfrac{1}{2}\times 101\times 4.25^2}{0.38}\\\Rightarrow F=3391.22\ \text{N}[/tex]
The force exerted on the floor is [tex]3391.22\ \text{N}[/tex].
Tameika makes a table about sensory organs
Eye
skin
brain
tongue
Which organ should be removed from the table?
A. eye
B. skin
C. brain
D. tongue
Answer:
I think its d
Explanation:
I'm not sure I'm sorry if I'm wrong
Which is true?
a) A changing magnetic field produces a constant perpendicular magnetic field.
b) A changing magnetic field produces a changing perpendicular magnetic field.
c) A changing magnetic field produces a constant parallel magnetic field.
d) A changing magnetic field produces a changing parallel magnetic field.
e) A changing magnetic field produces an electric field.
Answer:
e) A changing magnetic field produces an electric field.
Explanation:
Ok, we start with a magnetic field and let's study how it affects the motion of a single electron. As the magnetic field changes, it will cause an electromotive force, that moves the electron, and because now we have a moving electron, now we will have an electric field. (Such that the direction of the electromotive force opposes the direction in which the magnetic field changes). This also can be deduced if we look at the third Maxwell's equation:
dE/dx = -dB/dt
This says that the spatial change in an electric field depends on how the magnetic field changes as time pass.
Then the correct option is e) A changing magnetic field produces an electric field.
PLEASE HELP! I'LL GIVE BRAINLEST
Answer:
In this conversation the Neil astronaut is right
How far could you walk backwards in one hour? Use your speed from the 10m test to calculate the answer. Show your work or you will not receive credit.
Answer: Sweetheart i'm not walking backward for an hour for your little assignment
Explanation: Do it yourself lazy! Have a great day!
g A velocity selector consists of crossed electric and magnetic fields. The electric field has a magnitude of 480 N/C and is in the negative z direction. What should the magnetic field (magnitude and direction) be to select a proton moving in the negative x direction with a velocity of 3.50 cross times 10 to the power of 5 m/s to go un-deflected
Answer:
B = 1.37 mT
Explanation:
Given that,
The magnitude of the electric field, E = 480 N/C
The speed of the proton, [tex]v=3.50 \times 10^5\ m/s[/tex]
We need to find the magnitude of the magnetic field. In a velocity selector, the electric field is balanced by the magnetic field. So,
[tex]qE=qvB[/tex]
Where
B is the magnetic field
[tex]B=\dfrac{E}{v}\\\\B=\dfrac{480}{3.5\times 10^5}\\\\B=1.37\times 10^{-3}\ T\\\\or\\\\B =1.37\ mT[/tex]
So, the magnetic field is equal to 1.37 mT.
CORRECT ANSWER GETS BRAINLIEST
Answer:
Wax melts as it absorb heat from flame
Explanation:
To know which option is correct, it is important that we know what chemical changes and physical changes are all about.
Chemical change is a change in which the process is not easily reversed and it produces new substance.
Physical change is more like the opposite of chemical change. In this change, the process is easily reversed and no new substance is produced.
Considering the options given above,
1. Iron combines with oxygen to produce rust is a chemical change since a new substance (rust) is formed and we can not reverse the process to get back iron and oxygen.
2. Wax melts as it absorb heat from flame is a physical change since no new substance is formed and we obtained the wax by allowing it to solidified.
3. Pure sodium explodes when dropped in water is a chemical change because we can not reverse the process to get back the sodium.
4. Glucose molecules are produced in plant leaf is also a chemical change.
From the illustrations above, it is evident that: 'Wax melts as it absorb heat from flame' is not a chemical
If a virtual image is formed 10.0 cm along the principle axis from a convex mirror of focal length-15.0 cm, how far is the object from the mirror
Answer:
U=30cm
Explanation:
All you have to do is to put
Mirror formula , 1/f=1/u + 1/v
You should be careful in sign convention .
Virtual image is negative
we take focal length of convex lens negative even if its not given and so on...
A rod that is 96.0 cm long is made of glass that has an index of refraction equal to 1.60. The rod has its ends ground to convex spherical surfaces that have radii equal to 8.00 cm and 19.1 cm. An object is in air on the long axis of the rod 19.9 cm from the end that has the 19.1-cm radius.
(a) Find the image distance due to refraction at the 19.1-cm radius surface.
(b) Find the position of the final image due to refraction at both surfaces.
(c) Is the final image real or virtual?
