To determine the height of a bridge above the water, a person drops a stone and measures the time it takes for it to hit the water. If the time is 2.3 s, what is the height of the bridge? Neglect air resistance.
a. 32 m
b. 52 m
c. 26 m
d. 14 m
e. 10 m
A stone dropped from a 26 m bridge, takes 2.3 s to reach the water.
A stone is dropped from a bridge and it experiences a uniformly accelerated rectilinear motion. It takes 2.3 s for the stone to reach the water.
We can calculate the height of the bridge, which is equal to the displacement of the stone, using the following kinematic equation.
[tex]s = ut + \frac{1}{2} a t^{2} = (0m/s)(2.3 s) + \frac{1}{2} (9.8m/s^{2} ) (2.3s)^{2} = 26 m[/tex]
where,
s: displacementu: initial speed (0 m/s)t: timea: acceleration due to gravity (9.8 m/s²)A stone dropped from a 26 m bridge, takes 2.3 s to reach the water.
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A 40kg box sits on a shelf 0.5m above the floor. An employee moves the box to a height of 1.8m above the floor. How much work did the employee do in moving the box? A)20J B)72J C)200J D)520J E)720J
Answer:
b)72
Explanation
work done= force* distance
work done=40*1.8
72J
what of the average speed from 4s from 8s
A.0.5m/s
B.1m/s
C.2m/s
D.3m/s
E.9m
=====================================================
Explanation:
At 4 seconds, the distance is 8 meters. Note the point (4,8)
At 8 seconds, the distance is 10 meters. The point here is (8,10)
Find the slope of the line through (4,8) and (8,10)
m = (y2-y1)/(x2-x1)
m = (10-8)/(8-4)
m = 2/4
m = 1/2
m = 0.5
The average speed on this interval is 0.5 m/s
-----------------
Another way to look at it:
We've gone from 8 meters to 10 meters, so that's a change of y = 2 meters.
During this, the time has changed from 4 seconds to 8 seconds, which is a difference of x = 4 seconds.
The velocity is the rate of change of distance over time
velocity = (change in distance)/(change in time) = y/x = 2/4 = 0.5 m/s
On an icy day, you worry about parking your car in your driveway, which has an incline of 12º. Your neighbor's driveway has an incline of 9.0º, and the driveway across the street is at 6.0º. The coefficient of static friction between tire rubber and ice is 0.15. Which driveway(s) will be safe to park in?
Answer:
Driveway across the street ([tex]\theta = 6^{\circ}[/tex]) is the only choice for a safe parking.
Explanation:
Let suppose that car is represented by a particle, then we proceed to construct its free body diagram and corresponding equations of equilibrium:
[tex]\Sigma F_{x'} = f - W\cdot \sin \theta = 0[/tex] (Eq. 1)
[tex]\Sigma F_{y'} = N-W\cdot \cos \theta = 0[/tex] (Eq. 2)
Where:
[tex]f[/tex] - Static friction force, measured in newtons.
[tex]N[/tex] - Normal force on the car from the ground, measured in newtons.
[tex]W[/tex] - Weight of the car, measured in newtons.
[tex]\theta[/tex] - Driveway inclination, measured in sexagesimal degrees.
By applying definitions of maximum static friction force and weight, we expand the system of equations presented above:
[tex]\mu_{s}\cdot N -m\cdot g\cdot \sin \theta = 0[/tex] (Eq. 1b)
[tex]N - m\cdot g \cdot \cos \theta = 0[/tex] (Eq. 2b)
Where:
[tex]\mu_{s}[/tex] - Static coefficient of friction, dimensionless.
[tex]m[/tex] - Mass of the car, measured in kilograms.
[tex]g[/tex] - Gravitational acceleration, measured in meters per square second.
Then, we substitute normal force and simplify the resulting expression:
[tex]\mu_{s}\cdot m\cdot g \cdot \cos \theta -m\cdot g \cdot \sin \theta = 0[/tex]
[tex]\mu_{s} = \tan \theta[/tex]
[tex]\theta = \tan^{-1}\mu_{s}[/tex] (Eq. 3)
Based on such result, we can conclude that if driveway inclination is greater than value reported, then car shall not be safe in case of parking. Our reference angle is: ([tex]\mu_{s} = 0.15[/tex])
[tex]\theta = \tan^{-1} 0.15[/tex]
[tex]\theta \approx 8.531^{\circ}[/tex]
By direct comparison, we find that driveway across the street ([tex]\theta = 6^{\circ}[/tex]) is the only choice for a safe parking.
Which of the following statements is accurate when considering the role of cognition in shaping behavior? A. Cognition helps determine if a consequence is influential enough to control behavior. B. Cognition will most likely decrease the chance for classical conditioning to work. C. One’s cognitive processes are irrelevant when it comes to shaping behavior. D. One’s cognitive processes only work in shaping behavior when a particular consequence is desired. Please select the best answer from the choices provided A B C D
Answer: the answer is A.
Explanation:
brainliest please?
Answer:
A.
Cognition helps determine if a consequence is influential enough to control behavior.
Explanation:
This is right on edg. 2020
[04.05] An atom has an atomic number of 12 and a mass number of 25. How many neutrons does the atom have?
Answer: is 13
Explanation:
Remi travels 160 meters in 4 seconds. What was Remi's initial speed if her final velocity was 6.9 m/s?
Answer:
73.1 m/s
Explanation:
Given:
Δx = 160 m
v = 6.9 m/s
t = 4 s
Find: v₀
Δx = ½ (v + v₀) t
160 m = ½ (6.9 m/s + v₀) (4 s)
v₀ = 73.1 m/s
what would you want the after life to be like. examples are heaven and hell ,reincarnation ,eternal darkness , reliving your live but different choices or become a ghost,
Answer:
i would want to be a dog or a cat
Explanation:
there just funny
what is science and examples with it
Answer:
science is the intellectual and practical activity encompassing the systematic study of the structure and behaviour of the physical and natural world through observation and experiment.
Explanation:
Explain the quantization of energy.
Answer:
The quantization of energy refers to the fact that at subatomic levels, energy is best thought of as occurring in discreet "packets" called photons. Like paper money, photons come in different denominations. ... Each photon contains a unique amount of discreet energy
Water is formed when two hydrogen atoms bond to an oxygen atom. The hydrogen and the oxygen in this example are different
They both are two different elements.SO the answer is Element
A vector has an x-component
of 6.15 m and a y-component
of -3.88 m.
Find the direction of the vector.
List the 4 things technology can be.
Technology can be the four things listed below...
PhonesComputersTVsPlaystation or XboxAnswer:
mechanical
electronic
medical
industrail and manufacturing
At a drag race, a jet car travels 1/4 mile in 5.2 seconds. What is the final speed of the
car and its acceleration?
Answer:
1609.3
Explanation:
Which describes elements in the first group of the periodic table?
Answer:
Alkali metals are the chemical elements found in Group 1 of the periodic table. The alkali metals include: lithium, sodium, potassium, rubidium, cesium, and francium.
Explanation:
Answer:
alkali metals
Explanation:
3. Let the pen return to its vertical position and suddenly pull the thread.
Q4. What happened to the thread tied on the pen?
Answer:
The thread will experience a force on it .
Explanation:
When thread is tied to pen it will experience force. Because the pen is Abit heavy , there is a force that is applied to it which will cause it to elongate , after a while the thread will stretch, elongate and can later experience deformation. When it experience that, the thread can break after deformation and it has losses it elasticity.
What is the difference between a fact witness and an expert witness?
Answer:
Unlike a fact witness, an expert is entitled to compensation for participation in the case. A key distinction between a fact witness and an expert witness is that an expert witness may provide an opinion. Fact witnesses must limit their testimony to facts in regard to evidence they may have observed or been involved.
Explanation:
there
Answer:
Unlike a fact witness, an expert is entitled to compensation for participation in the case. A key distinction between a fact witness and an expert witness is that an expert witness may provide an opinion. Fact witnesses must limit their testimony to facts in regard to evidence they may have observed or been involved.
Explanation:
E2020
What forces cause acceleration?
Answer:
friction, should be correct i think!
S1-CA-PHY41
The graph below represents the motion of a car during a 3.0 s time interval. What is the total displacement
of the object at the end of 3.0s
Answer:
The total displacement of the object is 20 m
Explanation:
Velocity vs Time Graph
It shows the behavior of the velocity as time increases. If the velocity increases, then the acceleration is positive, if the velocity decreases, the acceleration is negative, and if the velocity is constant, then the acceleration is zero.
The distance covered by the car can be calculated as the area behind the graph.
The total area can be calculated in two parts: One triangle from t=0 sec to t=2 sec, and one rectangle from t=2 sec to t=3 sec.
The area of a triangle is
A1= B*H/2, where B is the length of the base, and H is the length of the Height. The base is B=2 seconds, and the height is H = 10 m/s, thus:
A1= (2 sec)*(10 m/sec)/2=10 m
The area of a rectangle is
A2=W*L, where W is the width, L is the length. W=1 sec, L=10 m/s, thus:
A2=(1 sec)*(10 m/sec) = 10 m
Total displacement= 10 m + 10 m = 20 m
The total displacement of the object is 20 m
An observer recorded the following data for the motion of a car undergoing constant acceleration.
Time (s)
3.0
5.0
6.0
Speed (m/s)
4.0
7.0
8.5
What was the magnitude of the acceleration of the car?
4.5 m/s2
O 2.0 m/s2
3.0 m/s2
1.5 m/s2
Option D) 1.5 m/s² is the correct answer.
The magnitude of the acceleration of the car is 1.5 m/s².
given the data in the question;
record of the observation;
Time(s) Speed(m/s)
3.0 4.0
5.0 7.0
6.0 8.5
Since its undergoing constant acceleration, we can make use any two from the three data recorded.
So, lets consider motion between t₁ = 3.0s and t₂ = 5.0s
Initial velocity at t₁ ; u = 4.0 m/s
final velocity at t₂; v = 7.0 m/s
Now, Time Elapsed; [tex]t = t_2 - t_1 = 7.0s - 5.0s = 2.0s[/tex]
To determine the magnitude of acceleration "a", we use the first equation of motion which says;
[tex]v = u + at[/tex]
we make "a" the subject of the formula
[tex]a =\frac{v - u}{t}[/tex]
so we substitute in our values;
[tex]a = \frac{(7.0m/s) - (4.0m/s)}{2.0s}[/tex]
[tex]a = \frac{3.0m/s}{2.0s}[/tex]
[tex]a = 1.5 m/s^2[/tex]
Therefore, the magnitude of the acceleration of the car is 1.5 m/s².
Option D) 1.5 m/s² is the correct answer.
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What are 3 parts of daltons atomic theory ?
If the number of wavelengths that pass a point in a given time increases, what has increased?
A.frequency
B.amplitude
C.intensity
D.wavelength
At what point of thermometric scale does Kelvin scale reading coincide with Fahrenheit scale
Answer:
At 574.59 Kelvin, the Fahrenheit temperature will be 574.59 °F.
Explanation:
We first need to find a relation between the Kelvin scale and the Fahranheit scale. We'll use the Celsius scale to relate them.
The Kelvin and Celsius scales are related by the formula:
K = °C + 273.15
Solving for °C:
°C = K - 273.15
Besides, the Kelvin and Celsius scales are related by:
°C = 5 ⁄ 9(°F - 32)
Now we find a temperature, say X, where both scales coincide. Equating both formulas:
X - 273.15=5 ⁄ 9(X - 32)
Multiply by 9:
9X - 2,458.35 = 5X - 160
Simplifying:
4X = 2,458.35 - 160=2,298.35
Solving:
X =2,298.35 / 4 = 574.59
At 574.59 Kelvin, the Fahrenheit temperature will be 574.59 °F.
When walking barefoot, Kevin can walk across the grass easily, but when he crosses the paved street, the street is hot and burns his feet. At the beach he walks quickly across the hot sand to the cool water. Why do some substances feel hot to his feet and others do not? Radiation is heat transfer through waves. Specific heat is the amount of energy required to raise the temperature of a substance 1 degree C.
16 William is sliding down a plastic slide on a playground. After he slides down the
ground, he feels a small electric shock when he touches a piece of metal. What has been built up on his body
that causes the shock?
A atoms
B electrons
C. neutrons
D. protons
Answer:Electrones
Explanation:Because its building up static
Answer:
B) Electrons
Explanation:
When William slides down the slide, the rubbing action between William and the slide causes electrons to be transferred to William and stored as a negative charge.
When he touches a piece of metal, the negative charge (i.e the build up of excess electrons), is released (discharged) into the metal causing what we know as a static shock.
What do you put in the bowl first? milk or cereal?
Answer:
i put cereal first
Explanation:
cereal
where is the image located when an objectis placed 30cm from a convex lens with a focal length of 10cm?
Answer:
15 cm
Explanation:
using the thin lens formula for convex lens
[tex]\frac{1}{f} = \frac{1}{p} + \frac{1}{q}\\ \\where f = focal length \\ p = object distance \\ q = image distance\\[/tex]
so,
[tex]\frac{1}{q} = \frac{1}{f} - \frac{1}{p} \\\\\frac{1}{q} = \frac{1}{10} - \frac{1}{30} \\\frac{1}{q} = \frac{2}{30}\\\frac{1}{q} = \frac{1}{15cm}[/tex]
so,
q = 15 cm
Who do you think took Ms. C's lunch?
Answer:
the main character
Explanation:
i think
Using the formula for kinetic energy of a moving particle k=12mv2, find the kinetic energy ka of particle a and the kinetic energy kb of particle
b. remember that both particles rotate about the y axis. express your answers in terms of m, ω, and r separated by a comma.
Complete Question
The complete question is shown on the first uploaded image
Answer:
The kinetic energy for particle a is [tex]K_a = \frac{9}{2} mr^2 w^2[/tex]
The kinetic energy for particle b is [tex]K_b = m w^2r^2 [/tex]
Explanation:
From the question we are told that
The mass of particle a is [tex]m[/tex]
The mass of particle b is [tex]2 m[/tex]
Generally the kinetic energy for particle a is mathematically represented as
[tex]K_a = \frac{1}{2} m v^2[/tex]
Here [tex]v_a[/tex] is the linear velocity of particle a which is mathematically represented as
[tex]v_b = w * 3r[/tex]
So
[tex]K = \frac{1}{2} m {w * 3r}^2[/tex]
=> [tex]K_a = \frac{9}{2} mr^2 w^2[/tex]
Generally the kinetic energy for particle a is mathematically represented as
[tex]K_b = \frac{1}{2} 2m v_b^2[/tex]
Here [tex]v_b[/tex] is the linear velocity of particle a which is mathematically represented as
[tex]v_b = w * r[/tex]
So
[tex]K_b = m (wr)^2[/tex]
=> [tex]K_b = m w^2r^2[/tex]
The kinetic energy of the particle in terms of angular speed (ω), mass of the object (m) and the radius of the path is [tex]\frac{1}{2} m \omega ^2 r^2[/tex].
The given parameters;
kinetic energy of the particle, K.E = ¹/₂mv²The kinetic energy of the of the particle in terms of the angular velocity is calculated as follows;
[tex]K_b = \frac{1}{2} m (\omega r)^2\\\\K_b = \frac{1}{2} m \omega ^2 r^2[/tex]
where;
m is the mass of the objectω is the angular speed of the objectr is the radius of the circular pathThus, the kinetic energy of the particle in terms of angular speed (ω), mass of the object (m) and the radius of the path is [tex]\frac{1}{2} m \omega ^2 r^2[/tex].
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How is Impulse related to Force?