Answer:
That is true.
Explanation:
When the input force is applied to the wheel, as it is with a doorknob, the axle turns over a shorter distance but with greater force, so the mechanical advantage is greater than 1.
Which of the following is a renewable source of energy?
Tick one box.
A bio-fuel
B coal
C natural gas
D oil
Answer:
A. boi-gas
Explanation:
This may help u
The block falls for a time t0, but the string does not completely unwind. What is the change in angular momentum of the pulley-block system from the instant that the block is released from rest until time t0?
The change in angular momentum of the pulley-block system is given as [tex]\omega = Rm_ogt_o[/tex]
Data;
time = t0mass = MoTorqueThis is the force that makes object rotate about an axis. The formula is given as the product between the radius about the axis and the force acting upon it.
The torque about point o is given as
[tex]\tau = R * m_og[/tex]
The change in angular momentum about point 'o' is the product between the torque and time.
[tex]\omega = \tau * t_o\\\omega = Rm_ogt_o[/tex]
The change in angular momentum of the pulley-block system is given as
[tex]\omega = Rm_ogt_o[/tex]
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Plant and animal cells are both eukaryotic cells that share many organelles and cell structures in common. However, each have unique organelles that perform specific functions in each cell type. Examine each of the lists of cell structures. Which of these are found in plant cells? Select ALL that apply.
A) nucleus, ribosomes, and chloroplasts
B) mitochondria, cell wall, chloroplasts
C) nucleus, mitochondria, and centrioles
D) cell membrane, ribosomes, small vacuoles
E) cell wall, central vacuole, and cell membrane
Answer:
A) nucleus, ribosomes, and chloroplasts
B) mitochondria, cell wall, chloroplasts
D) cell membrane, ribosomes, small vacuoles
E) cell wall, central vacuole, and cell membrane
Explanation:
It cannot be C as the list features centrioles, which is an animal-cell only structure.
Which of the following can only be a situation of increasing temperature?
1. The phase change of the material is going from water to solid
2. The height of the object is increasing
3. The objects speed in increasing at a constant rate
4. The average kinetic energy of the particles of a material is increasing
Increasing the temperature causes an increase in the average kinetic energy of the particles of a material.
What is average kinetic energy of particles?The average kinetic energy of particles is the energy possessed by particles due to their constant motion.
The constant motion of particles occurs due to the energy acquired by the particles, when the temperature of the particles increases, the average kinetic energy increases which in turn increases the speed of the particles.
Thus, we can conclude that, increasing the temperature causes an increase in the average kinetic energy of the particles of a material.
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Need help with this question. Thirty points.
[tex]1)\\\\\text{Kinetic energy,}\\\\E_k = \dfrac 12 mv^2 \\\\\implies m = \dfrac{2E_k}{v^2} = \dfrac{2\times 4500}{30^2}=10~ kg\\ \\2)\\\\\text{Kinetic energy,}\\\\E_k = \dfrac 12mv^2 \\\\\implies v^2 = \dfrac{2E_k}m\\\\\implies v = \sqrt{\dfrac{2E_k}{m}}=\sqrt{\dfrac{2 \times 320}{\dfrac{20}{9.8}}}= 17.709 ~ ms^{-1}\\\\3)\\\\\text{Kinetic energy,}\\\\E_k=\dfrac 12 mv^2=\dfrac 12 \times 50 \times 10^2=2500 ~J\\\\\\[/tex]
[tex]4)\\\\\text{Potential energy,}\\\\E_p =mgh = 5\times 9.8\times 1.5 = 73.5 ~J[/tex]
An object absorbs red, orange, yellow, blue, indigo, and violet light. What color is it?
A. blue
B. green
C. indigo
D. red
Answer: B. Green
Explanation:
Since the object absorbs all the other options listed here, it will reflect green light. This makes the object appear green to our eyes.
Blue (A), indigo (C), and red (D) are listed in red, orange, yellow, blue, indigo, and violet. Green is not, so this is our answer.
Fun fact:
An example of this is grass!
Answer:
green
Explanation:
the distibution on the condutor
The flow of electrons causes charge dispersion. Due to the ability of conductors to transmit electrons from one particle to another, a charged item will always spread its charge until the overall repulsive interactions between surplus electrons are minimized.
A thin 1.5 mm coating of glycerine has been placed between two microscope slides of width 0.8 cm and length 3.9 cm . Find the force required to pull one of the microscope slides at a constant speed of 0.28 m/s relative to the other.
The force required to pull one of the microscope sliding at a constant speed of 0.28 m/s relative to the other is zero.
Force required to pull one end at a constant speedThe force required to pull one of the microscope sliding at a constant speed of 0.28 m/s relative to the other is determined by applying Newton's second law of motion as shown below;
F = ma
where;
m is massa is accelerationAt a constant speed, the acceleration of the object will be zero.
F = m x 0
F = 0
Thus, the force required to pull one of the microscope sliding at a constant speed of 0.28 m/s relative to the other is zero.
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a right angled triangle has 5cm opposite side, 9cm adjacent side. find length of hypotunise
Hypotenuse be H
Apply Pythagorean theorem
[tex]\\ \sf\Rrightarrow H^2=P^2+B^2[/tex]
[tex]\\ \sf\Rrightarrow H^2=5^2+9^2[/tex]
[tex]\\ \sf\Rrightarrow H^2=25+81[/tex]
[tex]\\ \sf\Rrightarrow H^2=106[/tex]
[tex]\\ \sf\Rrightarrow H=\sqrt{106}cm[/tex]
A boy stands 190m from a high wall and claps his hands,if he hears an echo 1.3 seconds later. calculate the speed of sound in air.
Answer:
292.31 m/s
Explanation:
If Distance (d) = 190m
Time (t) = 1.3s
Speed of sound in air (v) =?
then
2d=vt
v=2d/t
v= 2×190/1.3
v=292.31 m/s
waves disturb a medium by causing the particles to_____.
Answer:
Oscillate
Explanation:
wave oscillates the particles of the medium around their equilibrium point.
If interstellar gas has a density of 1 atom/cm3, how big a volume of material must be used to make a star with the mass of the Sun
The volume of the material that must be used to make a star with the mass of the sun is 1.2×10⁵¹ m³.
What is volume?Volume is the amount of space occupied by an object or a plane figure.
To calculate the volume of the material that must be used to make a star with the mass of the sun, we use the formula below.
Formula:
D = m/V............ Equation 1Where:
D = Density of the interstellar gasm = mass of the sunV = Volume of the materialMake V the subject of the equation
V = m/D........... Equation 2From the question,
Given:
m = mass of the sun = 1.9891×10³⁰ kgD = 1 atom/cm³ = 1.66×10⁻²¹ kg/m³Substitute these values into equation 2
V = ( 1.9891×10³⁰)/(1.66×10⁻²¹)V = 1.2×10⁵¹ m³Hence, The volume of the material that must be used to make a star with the mass of the sun is 1.2×10⁵¹ m³.
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Why do you think we need evidence to be able to continually test theories about the composition and origin of our solar system and galaxies?
We need evidence to be able to continually test theories about the composition and origin of our solar system and galaxies in order to verify the theories and to make laws.
What is theory?A theory is an explanation for observations of the natural world that has been carried by using the scientific method, and which brings together many facts.
So we can conclude that we need evidence to test theories about the composition and origin of our solar system in order to verify the theories and to make laws.
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The SI unit for weight is ________.
A. mass
B. kilogram
C. newton
D. acceleration of gravity
E. weight
Answer:
Newton
Explanation:
The SI unit for weight is newton.
.
A
saloon car starting from rest will accelerates
to velocity of 48 km/h in 10 seconds. calculate
the
aceleration-
What’s the answer ?
Answer:
47
Explanation:
48km:1hr (10sec×60min=600hr)
¥ :600hr
1hr÷¥=1. 48×600÷1=2800
2800÷60=47
47 will be the acceleration
[tex]\text{Initial velocity,}~ u = 0 ~ ms^{-1}\\\\\text{Final velocity,}~ v = 48~kmh^{-1} = \dfrac{48\times 1000}{3600} ms^{-1} = 13.33 ms^{-1}\\ \\\text{Time,}~ t = 10~ sec\\\\\text{Acceleration,}~ a = \dfrac{v-u}{t} = \dfrac{13.33-0}{10} = \dfrac{13.33}{10} = 1.33 ~ ms^{-2}\\\\\text{Hence the acceleration of the car is}~ 1.33 ~ms^{-2}.[/tex]
A popcorn-maker transfers 250J of energy into other energy stores every second. What is its power?
Now
[tex]\\ \sf\rightarrowtail Power=\dfrac{Work\:done}{Time\:taken}[/tex]
[tex]\\ \sf\rightarrowtail Power=\dfrac{250}{1}[/tex]
[tex]\\ \sf\rightarrowtail Power=250W[/tex]
a hunter shoots a stone from his catapult with an initial velocity of 40 m per seconds add elevation of 60 degree with the aim of hitting a bird 145n away.
1. calculate the time of flight
Answer:
approximately 7 seconds
Explanation:
The given scenario is just an example of Projectile Motion.
In this question, we are given:
- Initial Velocity (u) = 40 m/s
- Angle of Elevation (θ) = 60 degrees
- Distance of Bird (s) = 145 meters [Not used for the time of flight]
Time of Flight:
[tex]T = \frac{2uSin(\theta)}{g}[/tex]
we will use g = 9.8 m/s/s since we are not told otherwise.
[tex]T = \frac{2(40)Sin(60 degrees)}{9.8}[/tex]
[tex]T = \frac{40\sqrt{3}}{9.8}[/tex]
T = 4.081(√3) seconds
rounded to 7 seconds
A person with a mass of 80 kg is at rest. What is their momentum? Write the
number only. *
Your answer
Answer:
0
Explanation:
because no distance covered by body
An unbalanced force acting on an object will cause it to? A. Increase in mass. B. Decrease in mass. C. Accelerate. D. Remain at rest.
Answer:
I think the object would accelerate.
Explanation:
When the unbalanced force hits the object, it transfers some of its force to the object, making it accelerate
Physics Momentum topic question. I will mark brainliest please help.
Answer:
10 m/s
Explanation:
Given
mass of ball 1, m1 = 1 kgmass of ball 2, m2 = 0.25 kginitial velocity of ball 1, u1 = 10 m/sinitial velocity of ball 2, u2 = 0 m/s [stationary]final velocity of ball 1, v1 = 7.5 m/smomentum of ball 2 after collision = 2.5 kg m/sSolving :
We do not require all of this informationOnly require points 2 and 6Momentum = mass x velocity⇒ velocity = 2.5 / 0.25⇒ velocity = 10 m/sIf a rock is thrown upward on the planet Mars with a velocity of 15 m/s, its height above the ground (in meters) after t seconds is given by H = 15t − 1.86t2. (a) Find the velocity (in m/s) of the rock after 1 second. 11.5404 Incorrect: Your answer is incorrect. seenKey 11.28 m/s (b) Find the velocity (in m/s) of the rock when t = a. m/s (c) When (in seconds) will the rock hit the surface? (Round your answer to one decimal place.) t = s (d) With what velocity (in m/s) will the rock hit the surface?
(a) The velocity (in m/s) of the rock after 1 second is 11.28 m/s.
(b) The velocity of the rock after 2 seconds is 7.56 m/s.
(c) The time for the block to hit the surface is 4.03.
(d) The velocity of the block at the maximum height is 0.
Velocity of the rockThe velocity of the rock is determined as shown below;
Height of the rock after 1 second; H(t) = 15(1) - 1.86(1)² = 13.14 m
v² = u² - 2gh
where;
g is acceleration due to gravity in mars = 3.72 m/s²v² = (15)² - 2(3.72)(13.14)
v² = 127.23
v = √127.23
v = 11.28 m/s
Velocity of the rock when t = 2 secondv = dh/dt
v = 15 - 3.72t
v(2) = 15 - 3.72(2)
v(2) = 7.56 m/s
Time for the rock to reach maximum heightdh/dt = 0
15 - 3.72t = 0
t = 4.03 s
Velocity of the rock when it hits the surfacev = u - gt
v = 15 - 3.72(4.03)
v = 0
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A plant is sitting on a table.
What, if any, forces are acting on the plant? (If there are forces acting on the
plant, include what direction they are acting.)
1 - Gravity (down)
11- Static Friction
111 - Normal (support) Force (up)
IV - Air Resistance to the left)
V - Applied Force (to the right)
#1
Yes gravity is acting downwards
#2
No static friction as its at rest#3
Normal reaction is applied upwards#4
No air resistance$5
No Applied force
what property of light is suggested by the formation of shadows
Answer:
The reflection and rectilinear propagation of light helps in the formation of shadows and also tells light doesn't penetrate opaque materials.
What do all waves transfer?
Question 1 options:
matter
energy
particles
water
Answer:
Matter
Explanation:
A wave is a disturbance that transfers energy from one place to another without transferring matter. Waves transfer energy away from the source, or starting place, of the energy.
Answer:
energy
Explanation:
I took the test think of hydropower dams
A satellite with a mass of 45 kg fires its rocket thrusters, which give an impulse of 1035 kg•m/s. What was the total change in the velocity of the satellite - that is, what was the total ΔV?
O 58 m/s
O 23 m/s
O 39 m/s
O 47 m/s
The total change in velocity of the satellite is 23 m/s
What is Impulse?In Physics, Impulse is the product of mass and change in velocity
Given:
mass = 46 kg
Impulse = 1035 kg•m/s
change in velocity = ?
impulse = mass * velocity
change in velocity = Impulse / mass
change in velocity = 1035 / 45
change in velocity = 23 m/s
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The frictional force between two surfaces at rest depends on which of the following?
Answer:
the two types of materials interacting (described by the coefficient μk) and how hard these two surfaces are pushed together (the normal force)
hope this helps and is it needs more let me know
If something weighs 2891N on earth, what’s it’s mass?
Answer:
289.1kg
Explanation:
because W=M*G, and M=W/G, so 2891N/10m/s²=289.1kg
If the force generated by the car to push it forward is 8,000 N, what can be said about the force opposing the car’s motion?
According to Newton's third law
Ever action has a equal and opposite reaction.So
[tex]\\ \rm\dashrightarrow F_{A}=-F_A[/tex]
Hence if applied force is 8000N opposing force is also 8000NAs car is pushed forward so the opposing force is less than 8000N
Answer:It is less than 8,000 N and greater than zero.
Explanation:
A circular ferris wheel that revolves at a constant rate once every 30 seconds. The
radius of the ferris wheel is 10 m. What is the normal force of the ferris wheel on a 10
kg toddler at the very bottom of the ferris wheel?
The normal force of the ferris wheel on a 10kg toddler at the very bottom of the ferris wheel is 102.41 N.
Centripetal force of the Ferris wheelThe normal force of the ferris wheel on a 10kg toddler at the very bottom of the ferris wheel is calculated as follows;
Fn = Fc + mg
Fn = mω²r + mg
where;
ω is the angular speed = 1 rev/30 s = 2π/30 s = 0.21 rad/sFn = 10(0.21²) 10 + 10(9.8)
Fn = 102.41 N
Thus, the normal force of the ferris wheel on a 10kg toddler at the very bottom of the ferris wheel is 102.41 N.
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When must scientific theories be changed
Answer:
when new information disproving the current theory becomes available.
Explanation:
hope this helps..
Answer:
when new evidence is discovered