Answer:
retina.
Explanation:
A boy whirls a ball on a string in a horizontal circle of radius 1 m. How many revolutions per minute must the ball make if its acceleration towards the center of the circle is to have the same magnitude as the acceleration due to gravity
Answer:
Nearest, the revolutions per minute will be 29.
Explanation:
Given that,
Radius of circle = 1 m
Acceleration a =g
We know that,
Angular frequency is defined as,
[tex]\omega=2\pi n[/tex]
Where, n = number of revolutions in one second
We need to calculate the revolutions in one second
Using formula of centripetal acceleration
[tex]a=\omega^2r[/tex]
Put the value of a and ω
[tex]g=(2\pi n)^2r[/tex]
[tex]n=\sqrt{\dfrac{g}{r}}\times\dfrac{1}{2\pi}[/tex]
Put the value into the formula
[tex]n=\sqrt{\dfrac{9.8}{1}}\times\dfrac{1}{2\pi}[/tex]
[tex]n=0.49[/tex]
We need to calculate the revolutions per minute
Using value for the revolutions per minute
[tex]n=0.49\times60[/tex]
[tex]n=29.4[/tex]
Hence, Nearest, the revolutions per minute will be 29.
A pile of bricks of mass M is being raised to the tenth floor of a building of height H = 4y above the ground by a crane that is on top of the building. During the first part of the lift, the crane lifts the bricks a vertical distance h1=3y in a time t1=4T. During the second part of the lift, the crane lifts the bricks a vertical distance h2=y in t2=T. Which of the following correctly relates the power P1 generated by the crane during the first part of the lift to the power P2 generated by the crane during the second part of the lift?
A. P2=4P1
B. P2=43P1
C. P2=P1
D. P2=34P1
E. P2=13P1
Answer:
The correct option is B
Explanation:
From the question we are told that
The mass of the pile is M
The height is H = 4 y
The vertical distance achieve during the first lift is [tex]h_1 = 3 y[/tex]
The time taken is [tex]t_1 = 4T [/tex]
The vertical distance achieve during the second lift is [tex]h_2 = y[/tex]
The time taken is [tex] t_2 = T [/tex]
Generally the velocity of the crane during the first lift is
[tex]v _1 = \frac{h_1}{t_1 }[/tex]
=> [tex]v _1 = \frac{3 y}{4T }[/tex]
Generally the velocity of the crane during the second lift is
[tex]v _2 = \frac{h_2}{t_2 }[/tex]
=> [tex]v _2 = \frac{ y}{T}[/tex]
Generally the power generated by the crane during the first lift is
[tex]P_1 = F_1 * v_1[/tex]
Here [tex]F_1[/tex] is the weight of the brick which is mathematically represented as
[tex]F_1 = M * g [/tex] , g is the acceleration due to gravity
So
[tex]P_1 = Mg * \frac{3y}{4T}[/tex]
Generally the power generated by the crane during the first lift is
[tex]P_1 = F_2 * v_2[/tex]
Here [tex]F_2[/tex] is the weight of the brick which is mathematically represented as
[tex]F_2 = M * g [/tex] , g is the acceleration due to gravity
So
[tex]P_1 = Mg * \frac{y}{T}[/tex]
The ratio of the first power generated to the second power is
[tex]\frac{P_1}{P_2} = \frac{Mg * \frac{3y}{4T} }{ Mg * \frac{y}{T} }[/tex]
=> [tex]\frac{P_1}{P_2} = \frac{3}{4}[/tex]
=> [tex]P_2 = \frac{4}{3} P_1[/tex]
A car stops in 130 m. If it has an acceleration of -5 m/s2 what was the cars starting velocity?
after
Variables:
Equation and Solve:
Answer:
We are given:
displacement (s) = 130 m
acceleration (a) = -5 m/s²
final velocity (v) = 0 m/s [the cars 'stops' in 130 m]
initial velocity (u) = u m/s
Solving for initial velocity:
From the third equation of motion:
v² - u² = 2as
replacing the variables
(0)² - (u)² = 2(-5)(130)
-u² = -1300
u² = 1300
u = √1300
u = 36 m/s
when hydrogen shares electrons with oxygen the outermost shell of the hydrogen atoms are full with how many electrons? and oxygens valence shell is full with how many electrons? because the valence shells of these atoms are full,the atoms are stable.
Answer:
2 and 8
Explanation:
please mark me brainiest I would really appreciate it.
A 10-ohm resistor has a constant current. If 1200 C of charge flow through it in 4 minutes what
is the value of the current?
A. 3.0 A
B 5.0 A
C. 11 A
D. 15 A
E. 20A
Answer:
B 5.0 A .
Explanation:
Hello.
In this case, since we know the charge (1200 C), time (4 min =240 s) and resistance (10Ω) which is actually not needed here, we compute the current as follows:
[tex]I=\frac{Q}{t}[/tex]
Then, for the given data, we obtain:
[tex]I=\frac{1200C}{4min}*\frac{1min}{60s}\\\\I=5A[/tex]
Therefore, answer is B 5.0 A .
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Which of the filling is a fossil fuel?
On a hot day, you sit on the edge of a pool and dip your feet into the water, causing changes to occur that are related to the physical and thermal properties of your feet and of the water. Select the statements that accurately describe what is happening, in terms of the heat and temperature of the objects and substances. There may be more than one accurate statement.
The true statements are;
Heat from your feet raises the temperature of the water.
Your feet transfer heat into the surrounding water, reducing the temperature of your feet. B and C
What are thermal changes?The term thermal changes has t do with the changes in the heat properties of the substance. We know that when you put your leg in water there is a thermal exchange between the water and your leg.
Owing to the fact that heat is transferred from your leg to the water, your leg will feel cool while the temperature of the water will increase slightly.
Having said all these, the true statements are;
Heat from your feet raises the temperature of the water.
Your feet transfer heat into the surrounding water, reducing the temperature of your feet.
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Missing parts;
On a hot day, you sit on the edge of a pool and dip your feet into the water, causing changes to occur that are
related to the physical and thermal properties of your feet and of the water. Select the statements that
accurately describe what is happening, in terms of the heat and temperature of the objects and substances.
There may be more than one accurate statement.
A. Cold from the water reduces the temperature of your feet.
B. Heat from your feet raises the temperature of the water.
C. Your feet transfer heat into the surrounding water, reducing the temperature of your feet.
D. Cold from the water moves into your warm feet.
i need help, for physics
A kangaroo is traveling at a velocity of 14.5 m/s for 7.5 seconds. The kangaroo’s force generated by its legs is 100 N. What is the mass of the kangaroo
A. 59kg
B. 63.28 N
C. 51.81 N
D. 51.81 kg
In which region does the ocean get the most sunlight throughout the year?
A. Near the equator
B. Near the poles
C. Northern mid-latitudes
D. Southern mid-latitudes
Answer: a
Explanation:
The ocean near the equator gets the most sunlight throughout the year, therefore the correct option is A.
What is the equator?The Equator is an imaginary line passing through the middle of a globe. It is equidistant from the North Pole and the South Pole, Its is a horizontal line residing at 0 degrees latitude.
Because of the revolving position of the earth in the solar system, The ocean near the equator gets the most sunlight throughout the year, therefore the correct option is A.
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how did the author describe the claws of uwang and salagubang?
Answer:
Describes them as sharp and dangerous.
Explanation:
The author describes the claws of uwang and salagubang as large, sharp, dangerous and scary. This creates a certain suspense in the story, as it leaves the reader apprehensive about the imminent danger that these claws pose to those who know them. However, despite their appearance, the claws are not as deadly as they seem because they can only hurt people who are pinched by them.
Six seconds after starting from rest, a car is moving at 15 m/s. What is the car's
average acceleration?
6 m/s2
0-5 m/s?
5 m/s2
2.5 m/s?
-2.5 m/s?
Answer:
2.5 m/s²
Explanation:
a = ∆v/∆t = (15 m/s)/(6 s) = (15/6) m/s² = 2.5 m/s²
Who was the first who traveled to the moon?
NEIL ARMSTRONG WAS THE FIRST MAN WHO TRAVELLED TO THE MOON.
Answer:
On July 20, 1969, Neil Armstrong became the first human to step on the moon.
Weight of a person's muscles, bones, tendons, and ligaments.
A. flexibility
B. lean mass
C. aerobic
A car moving at a speed of 8.0 m/s merges onto the highway and accelerates at a rate of
3.0 m/s2. How fast is it moving after travelling for 54 meters?
[tex]\large\underline{\underline{\red{\sf \blue{\longmapsto} Step\:-\:by\:-\:step\: Explanation:-}}}[/tex]
As per the data in Question,
Initial velocity of car = 8m/s (u)Final velocity of car = ? (v) .Acceleration of the car = 3.0m/s².Distance travelled by the car = 54m .Using the third equation of motion :-
[tex]\boxed{\red{\bf\purple{\dag}\:\:2as\:=\:v^2\:-\:u^2}}[/tex]
Substituting the respective values ,
⇒ 2as = v² - u² .
⇒ 2 × 3 × 54 = v² - 8²
⇒ 324 + 64 = v² .
⇒ v² = 388.
⇒ v = √388 .
⇒ v = 19.69 m/s ≈ 20m/s .
Hence the required answer is 19.69 m/s.
Two identical items, object 1 and object 2, are dropped from the top of a 50.0m50.0m building. Object 1 is dropped with an initial velocity of 0m/s0m/s, while object 2 is thrown straight downward with an initial velocity of 13.0m/s13.0m/s. What is the difference in time, in seconds rounded to the nearest tenth, between when the two objects hit the ground
Answer:
Δt = 1.1 s
Explanation:
Given information:
H= 50.0 m
g= 9.8 m/s²
Object 1v₀ = 0[tex]H = \frac{1}{2} * g* t^{2}[/tex]
Solving for t, we get:
t₁= 3.2 s
Object 2v₀ = 13 m/sWe can find the final velocity for the object when it hits the ground, using the following expression:
[tex]v_{f}^{2} - v_{o}^{2} = 2*g*H[/tex]
Solving for vf, we get:
vf = 33.9 m/s
Applying the definition of acceleration, being this acceleration the one due to gravity (g), we can write the following equation:
[tex]v_{f} = v_{o} + g*t[/tex]
(Assuming the downward direction to be positive).
Solving for t, we get:
t₂ = 2.1 s
So the difference in time when both objects hit the ground, it's simply
Δt = t₂ - t₁ = 3.2 s - 2.1 s = 1.1 s
1. A hot air balloon weighing 30 N is tied to the ground by a string to prevent
from floating off the ground. The volume of the balloon is 20 m and the
density of air is 1.3 kgm ?. Find:
a. upthrust acting on the balloon. Take g = 10 ms 2.
b. force exerted by the rope on the balloon?
Answer:
a) FB = 260 [N]
b) FT = 230 [N]
Explanation:
In order to solve this problem we must use a static analysis, since Globe does not move. For a better understanding in solving this problem, a free body diagram with the forces acting on the globe is attached.
The buoyant force acts upward as it causes the balloon to tend to float, the weight of the balloon tends to lower the balloon and the downward tension force does not allow the balloon to float
The buoyant force is defined by the following equation:
FB = Ro*V*g
where:
FB = Buoyant force [N]
Ro = density of the air = 1.3 [kg/m^3]
V = volume of the balloon = 20 [m^3]
g = gravity acceleration = 10 [m/s^2]
FB = 1.3*20*10 = 260 [N]
Now we do a sum of forces equal to zero in the y-axis
FB - 30 - FT = 0
260 - 30 = FT
FT = 230 [N]
Why is our (a person's) gravitational pull NOT as strong as the Earth's gravitational pull
on us?
Gravity doesn't act on us
The Earth is closer to us than the Moon
Our mass doesn't change so the pull is really the same
We are much smaller than the Earth.
Answer:With gravity, two things with mass will want to move toward each other. However, we humans don't feel our gravity pulling on another person because it's not very big, but we do all feel the pull of Earth's gravity all the time - we're not all floating in the air, because that would be happening without Earth's gravity!
Explanation:
A 1870 kg car traveling at 13.5 m/s collides with a 2970 kg car that is initally at rest at a stoplight. The cars stick together and move 1.93 m before friction causes them to stop. Determine the coefficient of kinetic friction between the cars and the road, assuming that the negative acceleration is constant and all wheels on both cars lock at the time of impact.
Answer:
The value is [tex] \mu = 0.72 [/tex]
Explanation:
From the question we are told that
The mass of the first car is [tex]m_1 = 1870\ kg[/tex]
the initial speed of the car is [tex]u = 13.5 \ m/s[/tex]
The mass of the second car is [tex]m_2 = 2970\ kg[/tex]
The distance move by both cars is s = 1.93 m
Generally from the law of momentum conservation
[tex]m_1 * u_1 + m_2 * u_2 = (m_1 + m_2 ) * v_f[/tex]
Here [tex]u_2 = 0[/tex] because the second car is at rest
and [tex]v_f[/tex] is the final velocity of the the two car
So
[tex]1870* 13.5+ 0= ( 1870 + 2970 ) * v_f[/tex]
=> [tex]v_f = 5.22\ m/s[/tex]
Generally from kinematic equation
[tex]v_f^2 = u_2^2 + 2as[/tex]
here a is the deceleration
So
[tex]5.22^2 = 0 + 2 *a * 1.93[/tex]
=> [tex]a = 7.06 \ m/s^2 [/tex]
Generally the frictional force is equal to the force propelling the car , this can be mathematically represented as
[tex]F_f = F[/tex]
Here F is mathematically represented as
[tex]F = (m_1 + m_2) * a[/tex]
[tex]F = (1870 + 2970) * 7.06 [/tex]
[tex]F =34170.4 \ N[/tex]
and
[tex]F_f = \mu * (m_1 + m_2 ) * g[/tex]
[tex]F_f = 47432 * \mu [/tex]
So
[tex] 47432 * \mu = 34170.4 [/tex]
=> [tex] 47432 * \mu = 34170.4 [/tex]
=> [tex] \mu = 0.72 [/tex]
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In which of the following locations would most likely find parenchyma cells? Leaves roots flowers bark
Answer:
I would guess its leaves
Answer:
Leaves
Explanation:
Big Bird decided to visit three of his friends. He got in his car and drove to Elmo’s house. It took Big Bird 10 minutes to drive the 5 miles. After visiting with Elmo for 30 minutes, he headed to Bert and Ernie’s house. This drive covered 15 miles and took 20 minutes. After a 25 minute stay, Big Bird headed to Cookie Monster’s house. The Cookie Monster’s house was 10 miles away and it took Big Bird another 15 minutes to get there. Because Cookie Monster wasn’t home, he was only there for 5 minutes. Big Bird then headed home, a trip that was 20 miles away and took him 25 minutes. What was the average speed for Big Bird’s whole trip (include his visiting time)?
Average speed =
(total distance)
divided by
(total time).
That's 28.57 miles per hour.
The average speed of Big Bird is 0.384 miles/minute.
What is average speed?The average speed of a body is the ratio of the total distance travelled and the time taken to travel that distance.
Average speed = total distance travelled/time takenThe total distance travelled = 50 miles
total time taken = 130 minutes
Average speed = 50 miles/130 minutes = 0.384 miles/minute.
Therefore, the average speed of Big Bird is 0.384 miles/minute.
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According to Newton's first law, which characteristic of a moving object would remain constant if there were no other
forces acting on it?
O size
c
mass
O shape
O speed
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Different kinds of substances have different properties. Compare and contrast the electrical properties of salts, acid , metals
Answer:
salts do not conduct electricity. unless u try to dissociate its ions,it cannot.
metals are good conductors of electricity.
acids also conduct electricity if you dissociate them into ions.
. A driver in a car travelling at a speed of 26.82m/s sees a deer in the middle of the road 100m
away. What is the minimum constant acceleration that is necessary for the car to stop?
5:04 PM
10/28/2020
Answer:
-3.60 m/s^2
Explanation:
The steam from a boiling pot of water is
A: conduction
B: Convection
C: radiation
D: Radiant energy
QUESTION 2
At the end of an investigation, what should be done if the results do NOT support the hypothesis?
O A Repeat your investigation to ensure your results are accurate and then modify your hypothesis if necessary.
OB. Repeat your investigation over and over again until you get the results that will support your original hypothes
O C. Check your measurement tools to ensure they are working.
OD. Change the topic of your investigation to one that will yield results that support a hypothesis.
Answer:
A. Repeat your investigation to ensure your results are accurate and then modify your hypothesis if necessary.
Explanation:
Having results that do not support the hypothesis is a common occurrence.
Hypotheses always depend on the data and experiment. If at the end of an investigation the results do not support the hypothesis, the investigation should be be repeated to further confirm this discovery.
And if there is still no correlation, then the hypothesis is not a reasonable explanation for the investigation and should be modified or rejected if necessary.
What is the function of a landfill
Answer:
A landfill is a carefully designed structure built into or on top of the ground, in which trash is separated from the area around it. Why are landfills important? Landfills contain garbage and serve to prevent contamination between the waste and the surrounding environment, especially groundwater.
Explanation:
Answer: A landfill is a carefully designed structure built into or on top of the ground, in which trash is separated from the area around it. Why are landfills important? Landfills contain garbage and serve to prevent contamination between the waste and the surrounding environment, especially groundwater.
Explanation: Google lol
Experiment 1: A study is done to determine which of two fuel mixtures allows a rocket to travel farther over a period of time. Rocket A, which requires additional equipment to keep it stable, is used to test one fuel mixture, and rocket B is used to test the other. Both rockets are identical aside from their mass. The results indicate that rocket B traveled farther than rocket A over the same period of time. Experiment 2: A double-blind experiment is performed to test whether a new drug is effective in lowering blood pressure. A random sample of subjects with high blood pressure is assigned to two groups. One group receives the new drug and the other group does not. Neither group is permitted to take any other medications during the experiment or to change their lifestyles in any way. The results of the experiment show that the drug is effective in lowering blood pressure.
Identify the experiment in which confounding occurs and the reason for its occurrence.
a. Neither experiment has a confounding variable.
b. Experiment 1 has a confounding variable related to the fuel mixtures. Varying the fuel mixture could skew the results of the study and should be kept constant.
c. Experiment 2 has a confounding variable related to the type of experiment. A double-blind experiment may increase the risk of the placebo effect and possibly skew the results.
d. Experiment 1 has a confounding variable related to the mass of the rockets. Any variation in mass may cause a discrepancy in the distance traveled.
e. Experiment 2 has a confounding variable related to the subjects used. Choosing a sample of subjects with high blood pressure instead of individuals with different blood pressure levels may confuse the results.
Answer: D
Experiment 1 has a confounding variable related to the mass of the rockets. Any variation in mass may cause a discrepancy in the distance traveled.
This is the answer to the question because:
Both experiments do have a confounding variable.Experiment 1 doesn't have to stay constant.A double-blind experiment will not do anything to the placebo.High blood pressure people will not make the results confusing.The answer has to be the option D. Hope this helps you!
I need help with this please
What kind of variation is there in the mechanical energy as the cart rolls down the ramp? Does this agree with your prediction? Explain.
Answer:
Em₀ = U = m g h , Em_{f} = K = ½ m v²
Explanation:
When a car is on a ramp it has a certain amount of mechanical energy. At the highest point of the ramp the mechanical energy is fully potential given by
Em₀ = U = m g h
As part of this energy descends down the ramp, part of this energy is transformed into kinetic energy and has one part of each, even though the sum remains the initial energy
Em = K + U = ½ m v² + mg y
y <h
when it reaches the bottom of the ramp it has no height therefore there is no potential energy, all of it has been transformed into kinetic energy
Em_{f} = K = ½ m v²
This energy transformation is in the case that the friction force is zero.
If there is a friction force, it performs work against the low car, it is reflected in an increase in the internal energy (temperature) of the car. In this case the energy in the lower part is less than the initial one by a factor
[tex]W_{nc}[/tex] = - fr L
therefore the numeraire values of the velocity are lower, due to the energy lost by friction.