An object is free falling near the surface of the earth. At a certain instant in time, it is falling downward at a rate 25.0 m/s. After 2.5 seconds, what are its acceleration and velocity?
Answers:
acceleration = 9.81 m/s^2velocity = 49.5 m/sThe values are approximate.
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Explanation:
When near the surface of the earth, the acceleration of gravity is roughly 9.81 m/s^2. This means that after each second passes, the velocity increases by roughly 9.81 m/s.
After 2.5 seconds, the velocity increases by 2.5*9.81 = 24.525 m/s = 24.5 m/s
If it was already going 25.0 m/s, then it bumps up to 25.0+24.5 = 49.5 m/s which is also approximate.
The acceleration of gravity stays the same when the object is close to the surface of the earth, so it stays at roughly 9.81 m/s^2
Side note: I'm ignoring air resistance (aka air friction or drag) since that greatly complicates things, and we would need to know the shape and surface area of the object. The material type would also be relevant info as well.
The dependent variable measured was the (a. initial momentums b. final momentums c. final velocity)
Answer:
B) Initial Momentums
Explanation:
A 20-N force acts on a 5-kg object at rest. How fast will
the object accelerate on a frictionless surface?
A. 15 m/s^2
B. 25 m/s^2
C. 4 m/s^2
D. 100 m/s^2
Answer:
C.
Explanation:
Force = Mass * Acceleration
So 20 = 5* Acceleration
4 = Acceleration
The acceleration of the object is 4 m/s².
To find the acceleration, the given values are:
Force = 20 N
Mass = 5 kg
Define acceleration.Definition:
As it was given as the values of Force and mass, here acceleration definition depends on the Newton's second law of motion.
Using the second law of motion, the force will be equal to the product of the mass and the acceleration.
As formula,
F = ma Newton
Here, to find acceleration,
a =f/ m
Substituting the values,
= 20 / 5
a = 4m/s².
So, the acceleration was 4 m/s². The Option C is the correct answer.
Learn more about acceleration,
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The force of gravitation between two cricket balls is extremly small but that between a cricket ball and earth is extremly is large?
Explanation:
Gravitational force depends upon the product of masses of the object. Earth has siginificantly greater mass than cricket ball. The product of masses for two ball is very low as compared to the product of earth and ball mass. That is why the gravitational force between earth and ball is relatively larger than two balls.
Answer:
The force of gravitation between the earth and the ball is large than the two balls.
Explanation:
The force of gravitation between the two bodies is directly proportional to the product of masses of two bodies and inversely proportional to the square of the distance between them.
So, when we take cricket balls , the masses of balls is very small and the distance is also small so the force between the two balls is small.
When we take earth and the ball, the mass of earth is very large eve distance is very large so the force between the earth and the ball is large as compared to the two balls.
The bohr Effect states that the lower the ph,?
Answer:
Explanation:
The Bohr effect describes how low pH (acidity) lowers the affinity of hemoglobin for oxygen, making hemoglobin more likely to offload oxygen in areas of low pH, which for reasons I'll get into, tissues in need of oxygen tend to have.
When solving projectiles you will often get two possible times for solutions. Sometimes a time will be negative and can be rejected. Other times both times will be positive and therefore possible. Explain why both times above make sense in the context of the given information used. Which time will you ultimately choose and why?
Context is attached below.
Answer:
The reason why times, 0.23 s, and 1.80 s makes sense is that a projectile passes through a given height level, which is lesser than the maximum height reached by the projectile, twice in its trajectory
Explanation:
The formula for the time of motion of a projectile is given as follows;
[tex]t = \dfrac{-V_{oy} \pm \sqrt{V_{oy} ^2 - 2 \cdot g \cdot \Delta y} }{-g}[/tex]
Therefore, when [tex]V_{oy} ^2 = 2 \cdot g \cdot \Delta y}[/tex], we have only one time value
When [tex]V_{oy} ^2 > 2 \cdot g \cdot \Delta y}[/tex], two time values can be obtained and both will be positive when we have;
[tex]V_{oy} > \sqrt{V_{oy} ^2 - 2 \cdot g \cdot \Delta y} }[/tex]
When [tex]V_{oy} < \sqrt{V_{oy} ^2 - 2 \cdot g \cdot \Delta y} }[/tex], one of the time values will be negative and can be rejected
Therefore, given that the times obtained above are 1.80 s, and 0.23 s, and both make sense due to the following reason;
In the path of the projectile motion of the basketball, there are two points in time at which the height of the basketball above the starting point is exactly 2 meters, given that the maximum height reached is more than 2 meters
The first time the basketball is 2 meters above the point it is shot is lesser of the two calculated time values, which is during the upward motion of the basketball before it reaches the maximum height, while the second time is, which is the larger calculated time, is the time that the basketball reaches the hoop, after flying past the highest point
Kevin used a pulley to lift a piano to the third floor of his apartment. His input work was 12,000 J and the output work was 10,000 J. What was the mechanical efficiency of the pulley?
A . 50%
B. 83.3%
C . 120%
D. 16.7%
Answer:
B
Explanation:
Eff = output work/input work ×100
Hence, Eff = 10000/12000 × 100
Eff = 83.3%
write multiples and sub-multiples of second
20 kg rodsis on the edge of a 80 m high de What is the rodes gracional potencial energy?
Answer:
Gpe = 15680 Joules
Explanation:
Gravitational potential energy (GPE) is an energy possessed by an object or body due to its position above the earth.
Mathematically, gravitational potential energy is given by the formula;
G.P.E = mgh
Where;
G.P.E represents potential energy measured in Joules.
m represents the mass of an object.
g represents acceleration due to gravity measured in meters per seconds square.
h represents the height measured in meters.
Given the following data;
Mass = 20 kg
Height = 80 m
We know that acceleration due to gravity is equal to 9.8 m/s²
To find the gravitational potential energy;
Gpe = mgh
Gpe = 20 * 80 * 9.8
Gpe = 15680 Joules
A 17Kg sitting on a shelf has a potential energy of 350J. How high is the shelf? Round your number to the nearest whole number
Answer:
[tex]{ \bf{potential \: energy = mass \times gravitation \times height}} \\ 350 = 17 \times 10 \times h \\ 350 = 170h \\ height = 2.06 \: metres[/tex]
Earth changes all the time making it a __ planet.
5. According to the law of reflection, the
is equal to the angle of incidence and a line drawn perpendicular to the reflecting surface.
O reflected ray
angle of reflection
O angle of refraction
Answer:
the answer is ....angle of reflection
Chiếu tia sáng lên một gương phẳng biết góc tới bằng 15⁰ hãy tính góc phản xạ bằng bao nhiêu
Answer:
góc phản xạ 15°
Explanatin
The particles of a substance stay close together but slide past one another as they move. When thermal energy is removed from the substance, the particles are forced into fixed positions by their attraction to one another. What change in state has occurred?
O A. Gas to solid
O B. Liquid to solid
O C. Solid to liquid
O D. Gas to liquid
Explanation:
The Answer is B.I think so may be it's wrong so kindly get any confirmation from your teacher about this
25)Two forces are acting on a block in opposite directions as shown in the figure above
(a) Calculate the net force acting on the block.
(b) In which direction will the net force tend to move the object?
(c) Will any other force try to oppose the motion of the block?
[tex]\boxed{ \sf{Answer}} [/tex]
____________________
(a) A = 5 kgwt
B = 10 N
First convert 5 kgwt to N,
[tex]5 \times 9.8 \\ = 49 \: N[/tex]
Net force [the forces are acting in 2 opposite directions]
[tex]A - B \: \\ = 49 - 10 \\ = 39 \: N[/tex]
____________________
(b) Since, the force is greater by A ↦the block will move towards B, i.e, to the right.
____________________
(c) Frictional force will try to oppose the motion of the block but since A has greater force than B, the frictional force will be resisted.
____________________
ʰᵒᵖᵉ ⁱᵗ ʰᵉˡᵖˢ ツ
꧁❣ ʀᴀɪɴʙᴏᴡˢᵃˡᵗ2²2² ࿐
Which object has potential energy but not kinetic energy?

A.
A battery in a pair of headphones

B.
A person riding an elevator upward

C.
A person climbing a ladder

D.
A car that is slowing down
Answer:
A.
A battery in a pair of headphones
Explanation:
Potenial energy - the energy possessed by a body by virtue of its position relative to others, stresses within itself, electric charge, and other factors.
11 e) Can a conductor be given limitless charge? Obtain the equivalent resistance of several resistors if (a) they are in series, (b) they are in parallel
Answer:
(e) no
(a) Rs = R' + R'' + R'''
(b) 1/Rp = 1/R' + 1/R'' + 1/R'''
Explanation:
11 e)
Practically it is not possible to give limitless charge to a conductor. It depends to the number of valence electrons.
(a) When the three resistances R'. R'' and R''' is in series combination.
Let they are connected to the voltage V and the current in each resistance is I.
According to Ohm's law
Voltage across R', V' = I R'
Voltage across R'', V'' = I R''
Voltage across R''', V''' = I R'''
So, let the equivalent resistance is Rs.
I Rs = I R' + I R'' + I R'''
Rs = R' + R'' + R'''
(b)
When the three resistances R'. R'' and R''' is in parallel combination.
Let they are connected to the voltage V and the current in each resistance is I', I''. I'''.
Current in R', I' = V/R'
Current in R'', I'' = V/R''
Current in R''', I''' = V/R'''
The equivalent resistance is Rp.
V/Rp = V/R' + V/ R'' + V/R'''
1/Rp = 1/R' + 1/R'' + 1/R'''
What is the change in velocity of a 22-kg object that experiences a force of 15 N for
1.2 seconds?
Answer:
Force = mass × acceleration
Acceleration:
[tex]{ \tt{15 = (22 \times a)}} \\ { \tt{a = \frac{15}{22} \: {ms}^{ - 2} }}[/tex]
From first Newton's equation of motion:
[tex]{ \bf{v = u + at}} [/tex]
Change = v - u:
[tex]{ \tt{v - u = (a \times t)}} \\ { \tt{v - u = ( \frac{15}{22} \times 1.2) }} \\ { \tt{v - u = 0.82 \: {ms}^{ - 2} }}[/tex]
Which of the following are true statements about the graph below? (choose 2)
The wavelength of the wave is decreasing as time goes on.
The frequency is decreasing as time goes on.
Something is damping the wave.
The amplitude of the wave is decreasing as time goes on.
Answer:
The amplitude of the wave is decreasing with time.
Something is damping the wave (the amplitude is decreasing with time)
Explanation:
The amplitde is measdured in the +/- y direction. Certainly you can observe that it is changing.
A damped wave is one whose vertical disdtance keeps going down until it is almost a straight line. Smething is causing that. The phenomenon is called damping.
So the answer is the last two. (c and d)
The frequency is measured on the x axis. If the distance between waves changes, then the frequency changes. Wavelength is also measured on the x axis. If the distance occupied by 2 consecutive waves changes , then the wave length changes.
Light of wavelength 530.00 nm is incident normally on a diffraction grating, and the first‑order maximum is observed to be 33.0∘ from the normal. How many slits per millimeter are marked on the grating?
Answer:
1028 slits/mm
Explanation:
We are given that
Wavelength of light, [tex]\lambda=530nm=530\times 10^{-9} m[/tex]
1nm=[tex]10^{-9} m[/tex]
[tex]\theta=33^{\circ}[/tex]
n=1
We have to find the number of slits per mm are marked on the grating.
We know that
[tex]dsin\theta=n\lambda[/tex]
Using the formula
[tex]dsin33^{\circ}=1\times 530\times 10^{-9}[/tex]
[tex]d=\frac{530\times 10^{-9}}{sin33^{\circ}}[/tex]
[tex]d=9.731\times 10^{-7} m[/tex]
1m=[tex]10^{3}mm[/tex]
[tex]d=9.731\times 10^{-7}\times 10^3[/tex]mm
[tex]d=0.0009731mm[/tex]
Number of slits=[tex]\frac{1}{d}[/tex]
Number of slits=[tex]\frac{1}{0.0009731}[/tex]/mm
Number of slits=1028/mm
Hence, 1028 slits/mm are marked on the grating.
Answer:
1027.6 lines per mm.
Explanation:
wavelength = 530 nm
order, m= 1
Angle = 33 degree
Let the slits per mm is 1/d.
So,
[tex]m \lambda = d sin A\\\\1\times 530\times 10^{-6} = d sin 33\\\\\frac{1}{d} = 1027.6 lines per mm[/tex]
Which component of the galaxy is shown in this image? Dust
Gas
Orbiting objects
Stars Do number 5 plz
Answer:
stars
those are stars in the galaxy
They are the stars in the galaxy given in above picture.
what is the answer to the question in the picture?
Answer:
yes,
Explanation:
because a compound contains two or more chemical elements chemically bond together.
How much money does a mixer use if the efficiency is 50% and it wastes 20J of energy ?
Answer:
Ei = 40J
Explanation:
Given the following data;
Efficiency = 50%
Energy output, Eo = 20 J
To find the amount of energy used by the mixer:
Efficiency = Eo/Ei * 100
Where;
Eo is the output energy.
Ei is the input energy.
Substituting into the formula, we have;
50 = 20/Ei * 100
Cross-multiplying, we have;
50Ei = 2000
Ei = 2000/50
Ei = 40J
Where are spores located on a fern? 1. On the root systems 2. In the flowers of the ferns 3. On the underside of the fronds 4. In the capsule of the sporophyte
In which condition is relative velocity known by adding the velocity od the first body and that of the second body ?
Answer:
when a two bodies A and B are moving at an angle 180° with each other then the relative velocity is the sum of bodies the velocity .i.e,
when the bodies move the opposite direction
then their relative velocity is the sum of individual velocities.
un litro de un gas es calentado a presión constante desde 20°C hasta 60°C que volumen final ocupará dicho gas?
Answer:
Final volume, V2 = 3 Litres
Explanation:
Given the following data;
Initial volume, V1 = 1 litre
Initial temperature, T1 = 20°C
Final temperature, T2 = 60°C
To find the final volume, we would use Charles' law;
Charles states that when the pressure of an ideal gas is kept constant, the volume of the gas is directly proportional to the absolute temperature of the gas.
Mathematically, Charles is given by;
V1/T1 = V2/T2
Making V2 as the subject formula, we have;
V1T2 = V2T1
V2 = (V1T2)/T1
Substituting into the formula, we have;
V2 = (1 * 60)/20
V2 = 60/20
Final volume, V2 = 3 Litres
the direction of applied force has to be_____ to the distance in order to say work is done
Answer:
Explanation:
The direction of the applied force has to be parallel to the distance an object moved in order to say that work has been done.
What was the role of gravity in the formation of the solar system?
A. Gravity caused the solar system to separate into individual
celestial bodies
B. Gravity caused the solar system to move closer to the Sun.
C. Gravity caused the solar system to compress into one larger
mass
D. Gravity caused the solar system to expand from a central point.
Answer:
Approximately 4.6 billion years ago, the solar system was a cloud of dust and gas known as a solar nebula. Gravity collapsed the material in on itself as it began to spin, forming the sun in the center of the nebula. ... Small particles drew together, bound by the force of gravity, into larger particles.
What's three pieces of evidence that Wegener used to support his theory ( Alfred Wegener’s hypothesis of continental drift states that the continents once formed a single landmass, broke up, and drifted to their present locations )
and why it is important to have several pieces of evidence when proposing a theory to describe phenomena like Alfred Wegener did.
Answer:
In the early part of the 20th century, scientists began to put together evidence that the continents could move around on Earth's surface. The evidence for continental drift included the fit of the continents; the distribution of ancient fossils, rocks, and mountain ranges; and the locations of ancient climatic zones.
What plate boundaries are in the alps
Answer:
The Alps consist of parts of the European Plate, a former Jurassic to Lower Cretaceous ocean floor, and the Adria Plate as part of the African Plate. A complicated pattern of overthrusted nappes characterizes the tectonic style. As a general rule, tectonically higher nappes originate further south.
Hope it helps you
