Answer:
A = (27.95 N, 21 N)
Explanation:
The polar co-ordinates are given as:
(r,θ) = (35 N, 37°)
Now, to convert this into polar co-ordinates (x, y), we will use following relations:
r² = x² + y²
(35)² = x² + y²
1225 = x² + y² ----------- equation (1)
and
tan θ = y/x
tan 37° = y/x
y = 0.753 x ------------------- equation (2)
Substituting this value in equation (1):
1225 = x² + (0.753 x)²
1225 = 1.567 x²
x² = 1225/1.567
x = √781.32
x = 27.95 N
using this value in equation (2)
y = (0.753)(27.95 N)
y = 21 N
Therefore, the vector can be represented in polar co-ordinates as:
A = (27.95 N, 21 N)
The displacement-time graph below represents the motion of a chart initially moving forward along a straight line.During which interval is the cart moving forward at a constant speed
AB
BC
CD
DE
The uniform motion ratios allow finding which intervals have constant velocity, the correct answers are
BC Positive velocity
CD Zero speed
DE Negative velocity
Kinematics studies the movement of bodies, establishing relationships between position, velocity and acceleration. In the special case that the acceleration is zero the motion is called uniform movement
v = [tex]\frac{\Delta_x}{\Delta t}[/tex]
Δx = v Δt
Where v is average velocity, Δx is the position variation and Δt is the time variation in the analyzed interval.
This equation we see that the relationship between displacement and time is linear, let's analyze each interval given in the graph
AB interval
In this interval the graph shows a curve whereby the movement is accelerated
BC interval
In this interval the graph is a line with a positive slope, therefore the movement is uniform with positive velocity
CD interval
In this part we have a line of zero slope
In motion it is uniform with zero speed, that is, the car is stopped
DE interval
The graph of this section is a line with a negative slope, consequently the velocity is negative.
With this analysis we see that the only interval that the movement is accelerated is the AB interval
In conclusion, using the uniform motion relationships we can find that intervals have constant velocity, the correct answers are
BC Positive velocity
CD Zero speed
DE Negative velocity
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a librarian pushes a 35kg box of books across the library floor. if the carpet resists with a friction force of 91N, what force must be applied by the librarian to accelerate the box at a rate of 0.50m/s
Answer:
F = 108.5 [N]
Explanation:
To solve this type of problem we must use Newton's second law, which tells us that the sum of forces must be equal to the product of mass by acceleration.
ΣF = m*a
where:
ΣF = sum of forces [N]
m = mass = 35 [kg]
a = acceleration = 0.5 [m/s²]
f = friction force [N]
F - f = m*a
F - 91 = (35*.5)
F = 91 + 17.5
F = 108.5 [N]
What is the net force on a bathroom scale when a 110 pound person stands on it? How do you know?
True or false. Atoms of a given element will have the same mass.
Answer:
True
Explanation:
Atoms of the same element will always have the same atomic mass or the mass listed in the periodic table.
PLEASE HELP!!!
When your muscle gets tired, it builds up the _______ and makes it more powerful.
momentum
blood
cells
--------------------------------------------------------------------------------------------------------------------------------
.
When it comes to fitness, at the end of the day the most important thing is ____________.
motivation
acceptance
sleep
--------------------------------------------------------------------------------------------------------------------------------
You can best measure your own resting heart rate when you first wake up in the morning.
True
False
____________________________________________________________________
Your normal heartbeat before exercise is called your ____________________.
heart rate
muscle
tissue
Answer:
asd
Explanation:
Please help with this!
On the way down the ball's velocity is Positive 9.8.
Option A) is the correct answer.
What is velocity:?
This refers to the speed at which an object moves in a given direction. It unit is meters per secocond, m/s.
What is acceleration?
This is the rate of change of velocity with respect to time. The speed and direction of the accelerating object are also very important. It unit is meters per second square, m/s².
What is Gravity?
This is the force that pulls a body toward the center of the earth. This force causes objects to fall freely. This free-falling object has an acceleration of 9.8m/s downward the earth. This is called acceleration gravity.
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A car’s velocity changes from 35 m/s to stopped in 13 seconds. Calculate
acceleration.
1) An object is dropped from the top of tower of hight 156.8m and at the same time another object is thrown vertically upward with the velocity of 77.1 m/s from the feetof tower,when and where the object meet
Answer:
The objects meet after 2.033722438s, at a height 136.5334679m from the ground.
Explanation:
Call the object being dropped A and the object being thrown B.
When the objects meet, the time ('t') for both objects will be equal, and the sum of their distances will be equal to 156.8m.
Figure out the distance for A in terms of time, t:
s = ut + (1/2)at²
= 0t +(1/2)(9.8)t²
=4.9t²
Figure out the distance for B in terms of time, t:
s = ut + (1/2)at²
=(77.1)t + (1/2)(-9.8)t²
=77.1t - 4.9t²
We now adding the distances gives us 156.8, so can write:
(4.9t²) + (77.1t - 4.9t²) = 156.8
77.1t = 156.8
∴ t = 2.033722438s
To find the distances, plug in this value for t:
For A: 4.9t² → 20.26653209m
For B: 77.1t - 4.9t² → 136.5334679m
The objects will meet 155.2 meters below the top of the tower after 15.7 seconds.
What is the height?The formula to calculate the time it takes for the object thrown upwards to return to the ground:
Time = 2 * Initial velocity / gravitational acceleration
Plugging in the values given in the question, you can calculate the time as follows:
Time = 2 * 77.1 m/s / 9.8 m/s^2 = 15.7 seconds
To determine when and where the objects meet, you can use the following formula to calculate the height of the object thrown upwards at any given time:
[tex]Height = Initial velocity * time - (1/2) * gravitational acceleration * time^2[/tex]
Plugging in the time calculated above and the initial velocity and gravitational acceleration given in the question, you can calculate the height of the object at the time it returns to the ground as follows:
Height = 77.1 m/s * 15.7 s - (1/2) * 9.8 m/s^2 * (15.7 s)^2 = -1.6 meters
This means that the object thrown upwards returns to the ground 1.6 meters below the point where it was launched. The object dropped from the top of the tower will also have fallen a distance of 156.8 meters in the same amount of time, so the two objects will meet at a point 156.8 meters - 1.6 meters = 155.2 meters below the top of the tower
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How do the independent and dependent variables in an experiment compare?
А.
The independent and dependent variables have no effect on each other.
В.
The dependent variable controls the independent variables.
C
The independent and dependent variables are the exact same as each other.
D
The independent variable controls the dependent variables.
Gregory's apartment catches fire, and he has to replace his sofa. Which policy will most likely cover the cost of replacing the sofa?
Answer:
Gregory's apartment catches fire, and he has to replace his sofa. Which policy will most likely cover the cost of replacing the sofa
i really need help with this
Answer:
The Moon
Explanation:
F=MA
160=98a
a=1.632563061m/s²
This value is closest to the Moon's value
I need help on this question
Answer:
at rest because time is passing and speed is still at 0
Explanation:
Someone in a car going past you at the speed of 32 m/s drops a small rock from a height of 2 m. How far from the point of the drop will the rock hit the ground? the acceleration due to gravity is 9.8m/s^2. answer in units of m.
Answer:
The rock will hit the ground at 20.44 m from the point of the drop
Explanation:
Horizontal Motion
It occurs when an object is thrown horizontally from a height h at an initial speed v.
The range or maximum horizontal distance traveled by the object can be calculated as follows:
[tex]\displaystyle d=v\cdot\sqrt{\frac {2h}{g}}[/tex]
When the small rock is dropped from a car at speed v=32 m/s, it starts a curved path that ends up when the rock hits the ground. The height is h=2 m, thus the range is:
[tex]\displaystyle d=32\cdot\sqrt{\frac {2\cdot 2}{9.8}}[/tex]
[tex]\displaystyle d=32\cdot\sqrt{0.4082}[/tex]
[tex]d=20.44\ m[/tex]
The rock will hit the ground at 20.44 m from the point of the drop
carbon has six protons. which model shows a neutral atom of carbon?
Answer:
It should have 6 electrons to be a neutral carbon atom
Calculate the average induced voltage between the tips of the wings of an airplane flying above East Lansing at a speed of 885 km/h. The wingspan of the airplane is 50.4 m, the vertical component of the Earth's magnetic field is 6.90×10-5 T.
Answer:
=0.855V
Explanation:
The induced voltage can be calculated using below expression
E =B x dA/dt
Where dA/dt = area
B= magnetic field = 6.90×10-5 T.
We were given speed of 885 km/h but we will need to convert to m/s for consistency of unit
speed = 885 km/h
speed = 885 x 10^3 m/hr
speed = 885 x 10^3/60 x60 m/s
speed = 245.8 m/s
If The aircraft wing sweep out" an area
at t= 50.4seconds then we have;
dA/dt = 50.4 x 245.8
= 123388.32m^2/s
Then from the expression above
E =B x dA/dt substitute the values of each parameters, we have
E = 6.90 x 10^-5 x 12388.32 V
E =0.855V
Hence, the average induced voltage between the tips of the wings is =0.855V
From Smallest to Largest
Moon
asteroid
meteorite
meteoroid
If the weight of an object on the moon is 1/6 of the weight of an object on earth. What
would be the weight of an object on the moon who has the weight of 4800 N on earth?
Answer:
1200 N
Explanation:
Answer:
1200N
Explanation:
Suppose a body of mass "m" and its weight on the moon is Wm (where W is the weight and "m" is the moon ;which means weight on the moon).Mass of the moon is "M"
and its radius is "R"
Weight of an object on the moon = "F"(Force)with which the moon pulls.
Wm = GM*m/r2
Weight of the same object on the earth is We(where W is the weight and "e" is the earth; which means weight on the earth).
Mass of the earth is 100 times of that of the moon.
Radius of the moon = R
Radius of the Earth = 4R
Weight of the object on the moon =
We = G100M*m/(4R)2(Pronounced 4 R square)
We = G100M*m/(16R)2(Pronounced 16 R square)
Wm/We = G * M * m * 16R2/R2 * g * 100M * m
=16/100
Therefore, 4800N on earth= 1200N on moon
HEY GUYS IS THIS TRUE OR FALSE????????
You run
completely around a 400m track in
100s. What was your average velocity?
Answer:
About 410
Explanation:
Answer:
4 m/s
Explanation:
Divide 400 m by 100 s to get 4 m/s. It also equals about 8.95 mph, 8.94775 mph to be exact.
Which option is the smallest particle that represents the compound carbon
dioxide?
A. A carbon dioxide molecule B. A carbon dioxide atom
C. A carbon atom and an oxygen atom
D. A carbon ion and an oxygen ion
HELPPPPP
PLEASE I NEED THIS ANSWER FASTTTT
Answer:The answer is A
Explanation: You can instantly eliminate b and d because an ion isn't mentioned, and it is impossible to have a carbon dioxide atom. C is incorrect because there has to be two oxygen's to create a carbon dioxide molecule.
Answer:
D. A carbon dioxide molecule
Explanation:
The south pole of one bar magnet is near the south pole of another bar magnet. What happens between the magnets?
A. They attract each other.
B. They twist toward each other.
C. They neither attract nor repel each other.
D. They repel each other.
PLEASE HELP!!!!!!!!!!
The south pole of one bar magnet brings near the south pole of another bar magnet, they repel each other. Therefore, option (D) is correct.
What are the magnets?A magnet can be defined as an object which is capable of producing a magnetic field and attracting unlike poles and repelling like poles. When a magnet dropped in iron filings, the iron filings cling to the end of the magnet as the attraction is maximum at the ends of the magnet.
Magnetic poles always exist in pairs whenever a magnet is suspended freely in the air, and always points in the north-south direction. The pole pointing towards the geographic north is called the North Pole and the pole pointing towards the geographic south is called the South Pole.
Similar poles of a magnet repel while unlike poles attract each other. The magnetic force between the two magnets is higher when the distance between these magnets is lesser. There are three types of magnets which are Permanent magnets, Temporary magnets, and electromagnets.
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FOR 45 POINTS PLS ANSWER FAST
1. coefficient of friction
force that opposes a sliding object
2. drag
a force that resists motion
3. friction
friction between a solid and a liquid or gas
4. rolling friction
a force that develops when a mass is accelerated by gravity; stated as Fw = mg
5. sliding or kinetic friction
force that opposes a rolling object
6. starting or static friction
force that opposes the start of motion
7. weight
the ratio of the force necessary to move an object (or keep it moving) and the normal force
Answer:
Other than gravity, the most commonly encountered force is what or the force that resists motion.
friction
the ratio of the force necessary to move an object (or keep it moving) and the normal force
coefficient of friction
friction between a solid and a liquid or gas
drag
a force that resists motion
friction
the force that presses two surfaces together and is directed perpendicular to the contact surface; on a level surface, its magnitude is equal to the force of the object's weight but in the opposite direction
normal force
force that opposes a rolling object
rolling friction
force that opposes a sliding object
sliding or kinetic friction
force that opposes the start of motion
starting or static friction
a force that develops when a mass is accelerated by gravity; stated as Fw = mg
weight
Friction is a force that resists what
motion
It occurs when a surface in motion rubs against another what
surface
What acts parallel to the surfaces that are moving against one another and in the direction opposite to the direction of the motion (represented by F).
Friction
riction is caused by the interaction of the what or what of each object sliding over each other.
atom or molecules
he more contact the atoms are able to make, the greater the what
frictional effect
A what surface will produce more friction (resistance) than a smooth surface
rough surface
The high points on one surface interact with the high points on the other surface allowing atoms and molecules to form temporary what
intermolecular bonds
The more bonds that are allowed to form, the greater the what
friction
he force that opposes the start of motion is referred to as what
starting or static friction
This force is caused by the what that form between two surfaces
tiny bonds
The pull required to keep the block moving at a constant speed in the example above is due to what
sliding or kinetic friction
What occurs as tiny intermolecular bonds are constantly being formed and broken.
Sliding friction
Sliding friction is also affected by the weight of the object and another force called the what
normal force
What is the force of the contact surface pressing opposite the weight of the object, as seen in the diagram below.
normal force
The normal force is always perpendicular to the what
contact surface
The ratio between the sliding friction and the perpendicular normal force is called the what of sliding friction
coefficient
What is represented by the Greek letter mu, μ,
coefficient
he third type of friction that can exist between solid surfaces is what or the force that opposes a rolling object
rolling friction
Friction can also exist between what
solids liquids and gases
Gases and liquids, such as air and water, offer what
resistance to motion
the opposing force between a solid and a liquid or gas
drag
45 POINTS!! IF ANYONE IS WILLING TO DO THIS YOU'RE A HERO
Pretend you are in a world with no friction or air resistance. You are on your bicycle at the top of a small hill. You kick off and without pedaling, you roll down the hill. How far will you go without pedaling in this pretend world? How does it compare with how far you might go in the real world? If there is a difference between the two worlds, why is this so? Explain as precisely as you can, using the law of conservation of energy in your explanation.
A 2-4 paragraph expository essay. This will include a full explanation of the normal conditions scenario and the frictionless world scenario in paragraph form.
No matter the format, the work must include:
A description of the bike’s behavior in our normal world with friction and air resistance, including distance traveled.
A description of the bike’s behavior in a frictionless, air resistance free world including distance traveled.
An explanation of forces at play in both scenarios and the kinetic and potential energy levels of the bike at various points in its travel down the hill. This will include application of the Law of Conservation of Energy using appropriate vocabulary words.
Spelling, grammar conventions, sentence structure and visual choices that allow your reader to access the information you are providing.
Answer:
you will go no where as far as you wish because there is no air resistance or friction, causing you to not stop. In the real world, you would stop a little bit after you got done with the hill because you have friction and air Resistance to bring you to a stop. There is a huge difference because in real life, there is a lot of friction and air resistance in the real world, which will eventually bring someone to a stop no matter how fast they are going.
Explanation:
An electric heater takes 1.2kwh in 30min at 120V having an efficiency of 99%.The heat energy required boil a certain amount of water is 99KJ.If the current taken by heater is 20 amp at 120V.Find the time required to boil water?
Answer:
Explanation:
Power of the heater = P watt .
P x .5 = 1200
P = 2400 W
If resistance of heater R
V² / R = 2400
120²/ R = 2400
R = 6 ohm .
heat to be produced = 99000 J
Current be I
I²R t x .99 = 99000
20² x 6 x t x .99 = 99000
t = 41.67 s
5 A swimming pool is 50m long. A
swimmer covers it in 50s. Calculate
the average speed of the swimmer.
the answer is 150 000 s2
The average speed of the swimmer is equal to 1 m/s.
What is the average speed?The average speed can be defined as the total distance traveled by the object in a specific time interval. The average speed can be defined as a scalar quantity as it possesses only the magnitude and does not have any direction.
The average speed can be determined from the ratio of the total distance the object covers to the time taken to travel that distance.
The equation for average speed can be written as follows:
Average speed = Total distance/Total time taken
Given, the distance covered by the swimmer = 50 m
The total time taken by the swimmer = 50 sec
The average speed of the train = 50/50 = 1 m/s
Therefore, the average speed of the swimmer is equal to 1 m/s.
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it is harmful to settle near the airport why
how does the electric current of an AC generator differ from that of a DC generator ?
A- it flows through the permanent magnets
B- it is much stronger
C- it is much weaker
D- it constantly reverses direction
The difference between the AC and the DC is that the AC current is always reversing. Option D
What is a generator?We have to know that the term generator has to do with a device that can be used in the production of electricity. The principle upon which the generator works is the principle of the electromagnetic induction.
Now we know that when we have a DC generator, the current that it is able to supply can be found to be constant but in the case of the AC generator, there is a constant change since the direction is reversing.
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The electric current of an AC generator differs from that of a DC generator in that it constantly reverses direction.
The correct option is D.
What are AC and DC generators?A mechanical device known as an AC generator transforms mechanical energy into AC or alternating current electrical power. Periodically, the electrical current in an AC generator changes direction.
A mechanical device known as a DC generator transforms mechanical energy into DC or direct current electrical power. The electrical current in a DC generator flows in one direction.
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A baseball is thrown horizontally at a rate of 40m/s toward a home plate 18.4 m away. How far below the launch height is the ball when it reaches home plate
Answer:
1.03684mExplanation:
Using the formula for calculating range expressed as;
R = U√2H/g where
R is the distance moves in horizontal direction = 18.4m
H is the height
U is the velocity of the baseball = 40m/s
g is the acceleration due to gravity = 9.8m/s²
Substitute the given parameters into the formula and calculate H as shown;
18.4 = 40√2H/9.8
18.4/40 = √2H/9.8
0.46 = √2H/9.8
square both sides;
(0.46)² = (√2H/9.8)²
0.2116 = 2H/9.8
2H = 9.8*0.2116
2H = 2.07368
H = 2.07368/2
H = 1.03684m
Hence the ball is 1.03684m below the launch height when it reached home plate.
Which of these is an example of a longitudinal wave?
Answer:
D. Sound waves
Explanation:
The following options are missing:
A. radio wave
B. X-rays
C. Light waves
D. Sound waves
There are two kinds of waves: longitudinal and transverse.
In longitudinal waves, the vibrations are parallel to the direction of wave travel. Examples of longitudinal waves include: sound waves and ultrasound waves.
In transverse waves, the vibrations are at right angles to the direction of wave travel. All electromagnetic waves (e.g. light waves, microwaves, radio waves and X-rays) are transverse waves.
A helicopter is dropping a package of rescue supplies to a group of stranded hikers. If it drops the supplies while it is hovering 172m above the hikers, how long does it take to hit the ground?
Answer:
This question is incomplete
Explanation:
This question is incomplete because of the absence of the average velocity at which the supplies are travelling in air. The formula to be used here if the completed question is obtained is
Average velocity (in m/s) = distance (m) ÷ time (s)
Since we are looking for the time, then time should be made the subject of the formula
time (in secs) = distance ÷ average velocity