Answer:
d
Explanation:
A student drops a 0.4kg ball from a height a of 49m above the ground. Neglect drag. Answer each of the following questions about the ball during the flight.
What is the magnitude of the net force on the ball?
What is the magnitude of the ball's acceleration?
How long does the ball take to hit the ground?
What is the ball's speed just before striking the ground?
• The only force acting on the ball, and thus the net force, is due to its own weight, with magnitude
w = m g = (0.4 kg) (9.8 m/s²) ≈ 3.9 N
pointing downward.
• The ball is in free fall, so its acceleration is g = 9.8 m/s² (also pointing downward).
• The ball is dropped from a height of 49 m, so its height y at time t is
y = 49 m - 1/2 g t ²
Set y = 0 and solve for t :
0 = 49 m - 1/2 g t ²
t ² = (98 m) / g
t = √((98 m) / g) = √(10) s ≈ 3.2 s
• The ball's velocity v at time t is
v = - g t
so that at the time found previously, the ball will have attained a velocity of
v = - g (3.2 s) ≈ -31 m/s
and thus a speed of about 31 m/s.
Calculate the speed for a car that went a distance of 254 km in 4 hours
time. *
s=d/t
63.5 km/h
36.5 km/hr
84.6 km/hr
Answer:
speed = 63.5 km/hr
Explanation:
let me know if that works
1. Horses with the greatest linear speed on a merry-go-round are located
A) near the center.
B) near the outside.
C) anywhere, because they all move at the same speed.
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What is the area of calm winds near the equator called?
doldrums
polar easterlies
trade winds
horse latitudes
Answer:
doldrums
Explanation:
Just need to type something more to be able to post
A computational model predicts the speed of a roller coaster car at different heights given its speed at the lowest height of its journey, which is at ground level. The speed at the lowest point is 30 m/s. What is the prediction for its speed when it is at a height of 20 m?(1 point)
18.8 m/s
15.9 m/s
37.5 m/s
22.5 m/
The answers to this test are:
1. What is the maximum speed when the conditions are mass = 450 kg, initial height = 30 m, and the roller coaster car is initially at rest?
24.2 m/s
2. A computational model predicts the maximum height that a roller coaster car can reach when the lowest height of its journey is at ground level, where it has a speed of 20 m/s. Given these conditions, what is the maximum height?
20.4 m
3. A computational model predicts the speed of a roller coaster car at different heights given its speed at the lowest height of its journey, which is at ground level. The speed at the lowest point is 30 m/s. What is the prediction for its speed when it is at a height of 20 m?
22.5 m/s
4. A computational model predicts the maximum potential energy a roller coaster car can have given its mass and its speed at the lowest point of its journey. Its mass is 350 kg, and it speed at a height of 0 m is 25 m/s. What is the prediction for its maximum potential energy?
109,375 J
5. What is the benefit of using simple computational models in a spreadsheet application, like the one used in this course, to predict mechanical energy and related values?
It is easy to calculate new scenarios.
The predicted speed of roller coaster at the given height is 22.5 m/s. Hence, option (d) is correct.
Given data:
The speed of roller coaster at the lowest point is, v = 30 m/s.
The height of coaster is, h = 20 m.
We need to predict the speed at the given height. So for that purpose, we can use the law of conservation of energy. As per the conservation of energy :
Total energy at height of 20 m = Total energy at bottom
PE + KE = PE' + KE'
Here,
PE and KE are the potential and kinetic energies at respective points.
So,
[tex]mgh + \dfrac{1}{2}mv'^{2}=0 + \dfrac{1}{2}mv'^{2}[/tex]
At bottom, the potential energy is zero.
Solving as,
[tex]gh + \dfrac{1}{2}v'^{2}=\dfrac{1}{2}v^{2}\\\\(9.8 \times 20) + \dfrac{1}{2} \times v'^{2}=\dfrac{1}{2} \times 30^{2}\\\\v' = 22.5 \;\rm m/s[/tex]
Thus, we can conclude that the predicted speed of roller coaster at the given height is 22.5 m/s. Hence, option (d) is correct.
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Answer: Dependent: temperature
Independent: time
Units: degrees per minute
Explanation: The dependent variable is temperature because it relies on the time to change. Time is the independent variable because it can't be altered by the other variable. The units are basically the variables and how they change.
The charge of an atom is......?
Humans are multicellular organisms with organs that specialize in specific functions. Even though the organs and their cells have specific functions, all cells must perform certain processes. Which process would be completed by all human cells?
Answer:
Cellular Respiration
Explanation:
A train is traveling north. it goes 200 km /hr for 2.5 hours how far did the train go.
Explanation:
The formula for finding distance is: speed × time
We must multiply:
200Km/h × 2.5 hours
This gives you 500 Km.
Remember: the formula to work out the distance - speed x time.
If the train speed is 200 km/h, it travels 200 km/h.
Now, we must multiply 200 by 2.5:
200 x 2.5 = 500
Our answer is 500 Kilometers.
Answer:
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Explanation:
You know where this comes from, right thoughtqueztionz?
A certain body is thrown at an angle of 30° to the horizontal with a speed of 20m/s. What is the time the body takes to reach the maximum height?
Answer: here is my answer
Explanation: Note also that the maximum height depends only on the vertical component of the initial velocity, so that any projectile with a 67.6 m/s initial vertical component of velocity will reach a maximum height of 233 m (neglecting air resistance)
what's the difference mass and weight
Answer:
Mass doesn't change.
Weight is measured based on gravitational pull.
Explanation:
. Since the man is walking at a constant velocity, he has what acceleration
The slope on a velocity vs time graph is the _______ of the object.Required to answer. Single choice.
Answer:
the slope of the line on a velocity versus time graph is equal to the acceleration of the object ctto google
The element selenium (Se) bonds with chlorine (Cl) to make the formula SeCl2 Chlorine is more electronegative than selenium. What is the name of this molecular compound?
Answer:
Selenium dichloride
Explanation:
Selenium (Se) and Chlorine (Cl) are both elements capable of combining together to form a compound with the chemical formula; SeCl2. Since the chlorine atom is more electronegative than selenium atom, the chlorine pulls more electrons towards itself to form an IONIC bond.
The SeCl2 compound formed is called Selenium dichloride as two atoms of Chlorine are needed to combine with one atom of Selenium to form the compound.
The name of the molecular compound is selenium dichloride (SeCl2).
• Due to sharing of electrons between selenium and chlorine, Selenium dichloride is considered as covalent compound.
• Both the elements are non-metals, and thus, would give rise to covalent bond.
• Selenium is the least electronegative element of the two, so it is written first.
• After that the more electronegative element is written, and then addition of suffix is done, that is, -ide.
• If atoms of an element is more than one, then prefixes are supplemented that is mono for 1 atom, di for two atoms, and tri for three atoms.
Thus, the name of the molecular compound is selenium dichloride.
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an object is dropped from a 145 m ledge. How fast it is moving just before it hits the ground
A top sprinter reached his maximum instantaneous velocity of 12.28 meters per second 7.17 seconds after leaving the blocks. Calculate his acceleration. All key steps must be shown.
I am very confused will you please help me!!
Answer:
Here we will assume two things.
His acceleration is constant until he reaches his maximum velocity and then he stops accelerating.
When he leaves the blocks, his velocity is "zero", meaning that the initial velocity is zero.
Then:
For the acceleration of the sprinter we will have a constant, A:
a(t) = A.
for the velocity we need to integrate over time, we will get
v(t) = A*t + v0
Where v0 is a constant of integration, and this is the initial velocity, as we already said, this will be zero, so the velocity equation is:
v(t) = A*t
We know that at t = 7.17 seconds, his velocity is 12.28m/s
then:
v(7.17s) = 12.28m/s = A*7.17s
12.28m/s/7.17s = 1.71 m/s^2 = A.
The acceleration is: 1.71 m/s^2 for 0 < t < 7.17s
0 m/s^2 for 7.17s < t.
This is because that was his maximum velocity, then after that time he can not accelerate more.
Which of the following best describes the type of bond formed when sodium reacts with chlorine?
Answer: ionic bond
Explanation: This type of chemical bond is called an ionic bond because the bond formed between two ions of opposite charge.
Supón que mañana por la mañana, cuando te despiertas y piensas en el día que tienes por delante, te preparas para ser tu mejor versión. ¿Qué harías o en qué pensarías a medida que te preparas para ese día?
Answer:
Si pienso en el día de mañana y cuando despierto pienso en el día que tengo por delante y preparo en mi mejor versión trataría de hacer las cosas que me gustan y dejar de lado las que me hacen mal y me estresan para poder disfrutar con total libertad.
Explanation:
Para poder ser la mejor versión de uno mismo una persona tiene que poder expresarse libremente, estar cómoda en el lugar que está para poder sentir y hacer lo que tiene ganas y lo que realmente le hace feliz.
Para algunos esa "mejor versión" puede tener que ver con exigencias físicas, como por ejemplo, entrenar para una carrera o prepararse para un evento deportivo. Para otras personas puede tener que ver con su potencial de estudio o académico por si tiene que rendir un examen, dar una exposición oral, una charla o una prueba laboral. Para otros puede tener que ver con perder miedos y soltar exigencias para poder ser libre de imposiciones externas.
Para que estas situaciones suceda la persona tiene que estar relajada, tranquila, en paz y pudiendo disfrutar en la mayor medida posible de todas sus cualidades y potencias.
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A circuit consists of a wire, a lightbulb, a switch, and a battery. What would
happen if the switch were replaced with a section of wire?
O A. The voltage and resistance would both decrease.
OB. The voltage would decrease, and the resistance would increase.
O C. The voltage would increase, and the resistance would decrease.
O D. The voltage and resistance would be the same.
Answer:
d
Explanation:
Why are some of the rocks on the moon older than the oldest known rocks on Earth?
Joseph remembers reading that for a particular pressure, P1, there is a maximum height to which a fluid can rise. He reasons that in this case the pressure (P2) must drop to zero so that the water can no longer flow to increased heights. He decides to check if the simulation can be made to demonstrate such conditions. He decides to make A2 as small as possible in the simulation (2.2 cm2) so that he increases the speed of the fluid in tube 2 as high as is possible (he decides to do this after examining the continuity equation). He then calculates the height of the fluid under these conditions where the pressure would fall to zero so that the fluid could no longer be made to flow under the conditions set up in the simulation. He then runs the simulation under the largest Δy allowed to check his calculation. What does Joseph calculate for the maximum height?
Answer:
h = P₁ / 9800
Explanation:
This is a fluid mechanics problem, let's write the Bernoulli equation at two points, the subscript 1 for the lowest point and the subscript of 2 for the point with the highest height.
P₁ + ½ ρ v₁² + ρ g y₁ = P₂ + ½ ρ v₂² + ρ g y₂
at the highest point P₂ = 0 and v₂ = 0,
P1 + ½ ρ v12 = ρ g (y₂ -y₁)
we use the continuity equation for the velocity at the lowest point
A₁ v₁ = A₂ v₂
Since the velocity at the highest point is zero, this implies from the equation that the velocity at the lowest point is also zero. In the no-flow condition
P₁ = ρ g (y₂ -y₁)
h = y₂-y₁
h = P₁ /ρ g
the density of water is ρ = 1000 kg / m³ and g = 9.8 m/s², we substitute
h = P₁ / 9800
Let's do a calculation, suppose that P₁ = 1 10⁵ Pa
h = 1 10⁵ / 9800
h = 10.2 m
What notecard word is defined: a substance or particles that a wave travel through.
outer space
electromagnetic
medium
mechanical
Answer:
medium
Explanation:
A substance or particle that wave travel through is called medium. There are two main types of such medium, some contains particles and some are vacuums.
Waves can travel through a vacuum which contains no particles. Some can also contain particles. Waves can interact in different ways with the medium.Convert 15° C to fahrenheit and kelvin
Answer:
59 degrees fahrenheit and 288.15 kelvin
Explanation:
Answer:
59 oF and 288 K
Explanation:
oF= 15 x 1.8 + 32= 59
K= 15+273 = 288
Kristina demonstrates a toy for her younger brother. The steps to operate the toy are listed below. Step 1. Push the toy down. Step 2. A spring compresses. Step 3. Release the toy. Step 4. The toy jumps into the air. Which best describes Step 4? Elastic potential energy changes to gravitational potential energy. Gravitational potential energy changes to elastic potential energy. Kristina does work to increase the gravitational potential energy. Kristina does work to increase the elastic potential energy.
Answer:
It's A
Elastic potential energy changes to gravitational potential energy
Explanation:
Step 4 can be described as "elastic potential energy changes to gravitational potential energy." The correct option is A.
What is the difference between potential energy and gravitational potential energy?Potential energy is the energy stored in an object due to its position, configuration, or state. It is a scalar quantity that describes the amount of energy that an object possesses by virtue of its position or configuration.
Gravitational potential energy, on the other hand, is a specific type of potential energy that is associated with an object's position in a gravitational field. It is defined as the amount of work that must be done to move an object from its current position to a reference position where its gravitational potential energy is zero, typically at an infinite distance away from the gravitational source.
The gravitational potential energy of an object depends on its mass, its height above a reference level, and the strength of the gravitational field in which it is located. The formula for gravitational potential energy is:
PE_grav = mgh
Where PE_grav is the gravitational potential energy, m is the mass of the object, g is the acceleration due to gravity, and h is the height of the object above the reference level.
So, potential energy is a general term for any type of energy stored in an object, while gravitational potential energy is a specific type of potential energy that is associated with an object's position in a gravitational field.
Here in the Question,
When the toy is pushed down in Step 1, energy is stored in the spring as elastic potential energy. As the spring compresses in Step 2, this potential energy is increased.
When the toy is released in Step 3, the compressed spring rapidly expands and releases the stored elastic potential energy. This energy is then converted into kinetic energy as the toy jumps into the air.
As the toy jumps into the air, its height increases and it gains gravitational potential energy. This energy is due to the toy's position in a gravitational field, and it is stored in the toy's interaction with Earth's gravitational pull.
Therefore, the energy transformation that occurs in Step 4 is from elastic potential energy to gravitational potential energy.
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1) Do liquids and gases also exert pressure?
Explanation:
Liquids also exert pressure in all directions on the walls of the container they are stored in. We see water coming out from leaking pipes and taps. ... Gases (Air) also exert pressure in all directions
Momentum:
3
Mass A has a mass of 10 kg while mass B has a mass of 20
kg. Which of these must be true?
Answer:
D
Explanation:
F=ma
a=F/m
according to option D, F is constant
so acceleration is inversely proportional to mass and A has half the mass of B. Hence, acceleration of A will be twice of B if same force is applied.
Which phase changes are endothermic?
Which characteristic does inertia describe
Answer:
Inertia is the resistance of any physical object to any change in its velocity. This includes changes to the object's speed, or direction of motion. An aspect of this property is the tendency of objects to keep moving in a straight line at a constant speed, when no forces act upon them.
Explanation:
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Answer:- how difficult it is to change an object's motion
Explanation:
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7. An airplane travels 4988.966 Km in 57 minutes. Calculate the average speed in
km/sec.
Answer:
wow easy
Explanation:
Select the correct answer. The formula for calculating power is work divided by time (power = work ÷ time). What are two ways of stating the same relationship? work = power ÷ time work = power × time time = work ÷ power time = work × power power = work × time
Answer:
work = power × time
time = work ÷ power
Explanation:
Power is defined as the rate at which work is done.
It is mathematically expressed as;
Power = [tex]\frac{work}{time}[/tex]
From this expression, if we cross multiply, we get;
work = power x time
Also, if we divide both sides by power, we get;
time = work ÷ power
