Answer:
a) θ = 58.3º
b) vfh = 13.7 m/s
c) g = -9.8 m/s2
d) h = 22.2 m
e) vfb = 15.5 m/s
Explanation:
a)
Assuming that gravity is the only influence that causes an acceleration to the water, due to it is always downward, since both directions are independent each other, in the horizontal direction, the water moves at a constant speed.Since the velocity vector has a magnitude of 26.0 m/s, we can find its horizontal component as follows:vₓ₀ = v * cos θ (1)where θ is the angle between the water and the horizontal axis (which we define as the x-axis, being positive to the right).Applying the definition of average velocity, taking the end of the hose like the origin, and making t₀ = 0, we can write the following expression:[tex]x_{f} = v_{ox} * t = v_{o} * cos \theta * t (2)[/tex]
Replacing by the givens of xf = 41.0m, t = 3.00 s, and v=26.0 m/s, we can solve for the angle of elevation θ, as follows:[tex]cos \theta = \frac{x_{f} }{v*t} = \frac{41.0m}{26.0m/s*3.00s} = 0.526 (3)[/tex]
⇒θ = cos⁻¹ (0.526) = 58.3º (4)b)
At the highest point in its trajectory, just before starting to fall, the vertical component of the velocity is just zero.Since the horizontal component keeps constant during all the journey, we can conclude that the speed at this point is just v₀ₓ, that we can find easily from (1) replacing by the values of v and cos θ, as follows:vₓ₀ = v * cos θ = 26.0 m/s * 0.526 = 13.7 m/s. (5)c)
At any point in the trajectory, the only acceleration present is due to the action of gravity, which accepted value is -9.8 m/s2 (taking the upward direction on the vertical y-axis as positive)d)
Since we know the time when the water strikes the building, it will be the same for the vertical movement, so, we can use the kinematic equation for vertical displacement, as follows:[tex]\Delta y = v_{oy} * t - \frac{1}{2} *g*t^{2} (6)[/tex]
Our only unknown remains v₀y, which can be obtained in the same way than the horizontal component:v₀y = v * sin θ = 26.0 m/s * 0.85 = 22.1 m/s (7)Replacing (7) in (6), we get:[tex]\Delta y = 22.1 m/s* 3.0s - \frac{1}{2} *9.8m/s2*(3.00s)^{2} = 22.2 m (8)[/tex]
e)
When the water hits the building the velocity vector, has two components, the horizontal vₓ and the vertical vy.The horizontal component, since it keeps constant, is just v₀x:v₀ₓ = 13.7 m/sThe vertical component can be found applying the definition of acceleration (g in this case), solving for the final velocity, as follows:[tex]v_{fy} = v_{oy} - g*t (9)[/tex]
Replacing by the time t (a given), g, and v₀y from (7), we can solve (9) as follows:[tex]v_{fy} = 22.1 m/s - 9.8m/s2*3.00s = -7.3 m/s (10)[/tex]
Since we know the values of both components (perpendicular each other), we can find the magnitude of the velocity vector (the speed, i.e. how fast is it moving), applying the Pythagorean Theorem to v₀ₓ and v₀y, as follows:[tex]v_{f} = \sqrt{(13.7m/s)^{2} +(-7.3m/s)^{2}} = 15.5 m/s (11)[/tex]
What is a path through which electric current can flow through a wire
A teacher places a warm bottles in a cooler filled with ice. Which statement best explains what happened over time?
A) Thermal energy will move from ice to water bottles
B) Coldness will move from the water bottles to the ice.
C) Coldness will move from the ice to the water bottlers
D) Thermal energy will move from the water bottle to the ice.
Answer:
D) Thermal energy will move from the water bottle to the ice.
Explanation:
Overtime, what happens is that thermal energy will move from the water bottle to the ice.
The water bottle is at a higher temperature compared to the ice. So, thermal energy will move from a place at higher temperature to one with lower temperature.
Thermal energy will stop moving until thermal equilibrium is attained. The water bottle will lose heat to the ice and by so doing it becomes colder. The ice will gain heat and begins to warm upA student places an object with a mass of m on a disk at a position r from the center of the disk. The student starts rotating the disk. When the disk reaches a speed of 0.8 m/s, the object starts to slide off the disk. What is the coefficient of static friction between the object and the disk?
mass=100 g, r= 0.75 m
Answer:
The coefficient of static friction between the object and the disk is 0.087.
Explanation:
According to the statement, the object on the disk experiments a centrifugal force due to static friction. From 2nd Newton's Law, we can represent the object by the following formula:
[tex]\Sigma F_{r} = \mu_{s}\cdot N = m\cdot \frac{v^{2}}{R}[/tex] (1)
[tex]\Sigma F_{y} = N - m\cdot g = 0[/tex] (2)
Where:
[tex]N[/tex] - Normal force from the ground on the object, measured in newtons.
[tex]m[/tex] - Mass of the object, measured in newtons.
[tex]g[/tex] - Gravitational acceleration, measured in meters per square second.
[tex]v[/tex] - Linear speed of rotation of the disk, measured in meters per second.
[tex]R[/tex] - Distance of the object from the center of the disk, measured in meters.
By applying (2) on (1), we obtain the following formula:
[tex]\mu_{s}\cdot m\cdot g = m\cdot \frac{v^{2}}{R}[/tex]
[tex]\mu_{s} = \frac{v^{2}}{g\cdot R}[/tex]
If we know that [tex]v = 0.8\,\frac{m}{s}[/tex], [tex]g = 9.807\,\frac{m}{s^{2}}[/tex] and [tex]R = 0.75\,m[/tex], then the coefficient of static friction between the object and the disk is:
[tex]\mu_{s} = \frac{\left(0.8\,\frac{m}{s} \right)^{2}}{\left(9.807\,\frac{m}{s^{2}} \right)\cdot (0.75\,m)}[/tex]
[tex]\mu_{s} = 0.087[/tex]
The coefficient of static friction between the object and the disk is 0.087.
A protein molecule in an electrophoresis gel has a negative charge. The exact charge depends on the pHpH of the solution, but 30 excess electrons is typical. What is the magnitude of the electric forceon a protein with this charge in a 1500 N/C electric field?
Answer:
The magnitude of the force = 7.2 × 10⁻¹⁵ C
Explanation:
The total quantization of charge q on an electron = n × e
where;
n = 30
e = 1.6 × 10⁻¹⁸ C
q = 30 × 1.6 × 10⁻¹⁸ C
q = 4.8 × 10⁻¹⁸ C
Now, the magnitude of the force is determined by using the formula:
F = qE
F = ( 4.8 × 10⁻¹⁸ C) ( 1500 N/C)
F = 7.2 × 10⁻¹⁵ C
How is the Moon thought to have formed
The levels of organization are Cell, Tissue, Organs, ____________, and Organism. what goes in the blank?
Answer:
Organ system because multiple organs make up an organ system and multiple organ systems make up an organism
A basketball is picked up off the ground and carried to the top of a platform that is 160 feet up. It is then dropped to the ground. The ball rebounds one-half the height each time it hits the ground. What is the total vertical distance the ball will travel from the moment it is picked up to the moment it reaches its maximum height after the fourth bounce
Answer:
Explanation:
The total distance travelled by ball before first bounce
= 160 + 160 = 320 ft
Distance travelled between first bounce and second bounce
= 80 + 80 = 160 ft
Distance travelled between second bounce and third bounce
= 40 + 40 = 80 ft
Distance travelled between third bounce and fourth bounce
= 20 + 20 = 40 ft .
Distance travelled in fourth bounce = 10 ft
Total distance travelled = 320 + 160 + 80 + 40 + 10
= 610 ft .
Two spherical objects have masses of 100 kg and 200 kg. Their centers are
separated by a distance of 40 cm. Find the gravitational attraction between
them.
Answer:
8.34 x 10⁻⁶N
Explanation:
Given parameters:
Mass 1 = 100kg
Mass 2 = 200kg
Distance of separation = 40cm = 0.4m
Unknown:
Gravitational force of attraction between them = ?
Solution:
To solve this problem, we use the expression below which is derived from the Newton's law of universal gravitation:
Fg = [tex]\frac{G x mass 1 x mass 2}{d^{2} }[/tex]
G is the universal gravitation constant = 6.67 x 10⁻¹¹
d is the separation
Now;
Fg = [tex]\frac{6.67 x 10^{-11} x 100 x 200}{0.4^{2} }[/tex] = 8.34 x 10⁻⁶N
A cell phone weighing 80 grams is flying through the air at 15 m/s what is the kinetic energy
Answer:
[tex]9\:\mathrm{J}[/tex]
Explanation:
Kinetic energy is given by the following equation:
[tex]KE=\frac{1}{2}mv^2[/tex], where [tex]m[/tex] is mass in [tex]\mathrm{kg}[/tex] and [tex]v[/tex] is velocity in [tex]\mathrm{m/s}[/tex].
Since the cell phone's mass is given in grams, we need to convert this into kilograms:
[tex]80\:\mathrm{g}\cdot \frac{1\:\mathrm{kg}}{1000\:\mathrm{g}}=0.08\:\mathrm{kg}[/tex].
Therefore, the kinetic energy of the cell phone is:
[tex]KE=\frac{1}{2}\cdot 0.08\cdot 15^2=\fbox{$9\:\mathrm{J}$}[/tex].
If a woman walks at a speed of 5 miles/hour for 3 hours, she will have walked how many miles?
The distance walked by the woman at the given speed an time, is 15 miles.
What is meant by speed?The speed of an object is defined as the rate of change of the distance travelled by the object.
Here,
Speed with which the woman is walking,
v = 5 miles/hour
Time taken by the woman for walking,
t = 3 hours
We know speed is the rate of change of distance,
v = d/t where d is the distance travelled by the woman
So, d = v x t
d = 5 x 3
d = 15 miles
Hence,
The distance walked by the woman at the given speed an time, is 15 miles.
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a) A bus of mass 760 kg requires 120 m to reach certain velocity value Vf. Ignore friction and drag forces and assume the bus engine exerts a constant forward force F. When the bus is towing a 330-kg small car, how long distance needed to reach same Vf? b) If the Vf of the bus is 28 m/s, what is the tension in the tow cable between bus and small car?
Answer:
Given : A bus of mass 760 kg requires 120 m to reach certain velocity value Vf.
the bus engine exerts a constant forward force F.
To Find : When the bus is towing a 330-kg small car, how long distance needed to reach same Vf?
Solution:
V² - U² = 2aS
V = Vf
U = 0
S = 120 m
=> Vf² - 0 = 2a(120)
=> Vf² = 240a
m = 760 kg
Force = F
F = ma
=> F =760 a
=> a = F/760
Vf² = 240F/760
Case 2 :When the bus is towing a 330-kg small car,
m = 760 + 330 = 1090 kg
a = F/1090
Vf² = 2aS
=> 240F/760 = 2 (F/1090) S
=> S = 120 x 1090 /760
=> S = 172.1 m
172.1 m distance needed to reach same Vf
Explanation:
. What is the atomic number for calcium?
an airplane normally flying at 80 km/h north encounters a wind from the west of 10km/h at right angle to its foward motion a crosswind what will its resultant velocity be ?
Answer:
v = 80.62 km/h
Explanation:
Given that,
An airplane normally flying at 80 km/h north encounters a wind from the west of 10km/h at right angle to its forward motion a crosswind.
We need to find the resultant velocity of the airplane. It can be calculated as follows :
[tex]v=\sqrt{80^2+10^2} \\\\v=80.62\ km/h[/tex]
So, the required velocity is 80.62 km/h.
While camping in a tent on a cold night, which would keep you warmer for a longer period of time. a 10 kg
bag of hot iron pellets or a 10 kg bag of hot water at the same temperature? Explain. PLEASE ANSWER
Answer:
a 10 kg bag of hot water at the same temperature
Explanation:
A 10kg bag of hot water at the same temperature will retain heat much better and keep the tent warmer at night compared to the iron pellet.
Water has a very large specific heat capacity. The specific heat capacity of water allows for it to retain heat better. It takes a larger amount of heat to warm water compared to iron which is a better conductor. In like manner, it takes more time for water to lose that amount of heat it has gained by the heating process. This is why it is a better choice to keep the room warmA potato with a mass of 0.25kg is resting on a table. Calculate the force that the potato exerts on the Earth.
Answer:
F = 2.45 [N]
Explanation:
The force that the potato exerts on the Earth is equal to the product of the potato mass by gravitational acceleration.
[tex]F=m*g[/tex]
where:
m = mass = 0.25 [kg]
g = gravity acceleration = 9.81 [m/s²]
[tex]F=0.25*9.81\\F=2.45[N][/tex]
The most common complaint among patients about their doctors is the time spent waiting in the doctor's office. Patients claim that doctors overbook appointments. Doctors claim that a significant number of patients fail to show or are late for their appointments. Doctors also note that as medical professionals they must tend to anyone who has need of their service. The medical profession is also uncertain because doctors never know when an emergency will occur. Considering the economic concepts of scarcity and economic resources, why must doctors book as many patients as necessary during office hours?
A doctor has the time and resources to choose how many patients to treat
A doctor, by law, must treat every patient who shows up in a medical facility
A doctor must make as much money as possible during normal business hours
A doctor's time is scarce and must be used effectively to see the most patients
Answer: B- a doctor, by law, must treat every patient who shows up in a medical facility
Explanation:
Cecily is inflating her bicycle tyre with the pump below. When she pushes the plunger down, it is doing work against the gas. This means that the plunger is transferring what to the gas particles?
The plunger is transferring energy to the gas particles.
What the plunger is transferring to the gas particles?When Cecily is applying pressure to the plunger, the gas inside is being compressed, and the speed of gas molecules increases.
When these air molecules enter the tire, adiabatically, the temperature of the gas rises.
It happens due to an increase in the average kinetic energy of the gas particles.
Thus, the gas particles receive energy from the plunger.
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A bicycle racer rides from a starting marker to a turnaround marker at 10 m/s. She then rides back along the same route from the turnaround marker to the starting marker at 16 m/s. What is her average speed for the whole race?
Answer:
12.31 m/s
Explanation:
If we recall from the previous knowledge we had about speed,
we will know that:
speed = distance/ time.
As such:
The average speed of the rider bicycle is
average speed = total distance/ total time
Mathematically, it can be computed as:
[tex]v_{avg} = \dfrac{d+d}{\dfrac{d}{v_1}+ \dfrac{d}{v_2}}[/tex]
[tex]v_{avg} = \dfrac{2d}{\dfrac{d}{10 \ m/s}+ \dfrac{d}{16 \ m/s}}[/tex]
[tex]v_{avg} = \dfrac{2}{\dfrac{1}{10 \ m/s}+ \dfrac{1}{16 \ m/s}}[/tex]
[tex]v_{avg} = \dfrac{2}{\dfrac{13}{80 \ m/s}}[/tex]
[tex]\mathbf{v_{avg} =12.31 \ m/s}[/tex]
3.
What is a star? Why does the sun appear so big whereas the other stars do not?
Ans.
Two microwave signals of nearly equal wavelengths can gener- ate a beat frequency if both are directed onto the same microwave detector. In an experiment, the beat frequency is 100 MHz. One microwave generator is set to emit microwaves with a wavelength of 1.250 cm. If the second generator emits the longer wavelength, what is that wavelength
Answer:
the longer wavelength is 1.2552 cm
Explanation:
given that
beat frequency [tex]f_{b}[/tex] = 100 MHz = 100 × 10⁶ Hz
λ₁ = 1.250 cm = 0.0125 m
we know that beat frequency [tex]f_{b}[/tex] of two simultaneous frequencies f₁ and f₂ is expressed as;
[tex]f_{b}[/tex] = | f₁ - f₂ |
we know that microwave travels at a speed of light, so for any electromagnetic wave traveling at speed of light c with wavelength λ; frequency is;
f = c / λ
hence our beat frequency [tex]f_{b}[/tex] becomes
[tex]f_{b}[/tex] = c ( 1/λ₁ - 1/λ₂)
to find the longer wavelength, λ₂
[tex]f_{b}[/tex] = c ( 1/λ₁ - 1/λ₂)
divide both side by c
[tex]f_{b}[/tex] /c = ( 1/λ₁ - 1/λ₂)
1/λ₂ = 1/λ₁ - [tex]f_{b}[/tex] /c
λ₂ = [1/λ₁ - [tex]f_{b}[/tex] /c ]⁻¹
so we substitute in our values
we know that speed of light c = 3 × 10⁸
so
λ₂ = [ (1/0.0125) - (100 × 10⁶ /3 × 10⁸) ]⁻¹
λ₂ = [80 - 0.3333 ]⁻¹
λ₂ = [79.6667 ]⁻¹
λ₂ = 0.01255 m
λ₂ = 0.012552 × 100 cm
λ₂ = 1.2552 cm
Therefore, the longer wavelength is 1.2552 cm
Sultan travels 40 km north then 60 km west to reach the stadium and watch the football match. What
is Sultan's displacement?
Answer:
sultan's displacement is
[tex]20 \sqrt{13} [/tex] km
How many joules does your 1600W electric hair dryer transfer if it takes 1 minutes to dry your hair?
____ joules
Answer:
96,000joules!!!
Explanation:
Hope this helps u
a car moved 60 meters west in 2hours what is its average velocity
Answer:
30 m/h
Explanation:
Have A Wonderful Day !!
what is the pressure on a swimmer 50 m below the surface of a lake
Answer:
P = 490500 [Pa]
Explanation:
The pressure at the bottom of a vessel and even of a lake or sea can be calculated by means of the following hydrostatic equation.
[tex]P=Ro*g*h[/tex]
where:
P = pressure [Pa] (units of pascal)
Ro = water density = 1000 [kg/m³]
g = gravity acceleration = 9.81 [m/s²]
h = elevation = 50 [m]
Now replacing:
[tex]P=1000*9.81*50\\P=490500[Pa][/tex]
how does a battery work?
Answer:
Essentials. A battery is a device that stores chemical energy and converts it to electrical energy. The chemical reactions in a battery involve the flow of electrons from one material (electrode) to another, through an external circuit. The flow of electrons provides an electric current that can be used to do work.
discuss how devastating a 7.7 - magnitude earthquake is.
Answer:
Explanation:
It’s devastating because when a earthquake is 7.7 magnitude the
describe measurement in our daily life
find the volume of an object with a density of 3.2 g/mL and a mass of 12 g.
Plz help this is so confusing
Answer:
5 Km/h
Explanation:
From the question given above, the following data were obtained:
Distance travelled = 10 Km
Time = 2 hours
Speed =?
Speed is simply defined as the distance travelled per unit time. Mathematically, it can be represented as:
Speed = distance travelled /time.
With the above formula, we can obtain the speed at which the duck is travelling as follow:
Distance travelled = 10 Km
Time = 2 hours
Speed =?
Speed = distance travelled /time.
Speed = 10 / 2
Speed = 5 Km/h
Thus, the duck is travelling at a speed of 5 Km/h
A ball rolling on the floor eventually comes to a stop. Which statement best describes this situation?
A) The energy on the macroscopic scale and the energy on the molecular scale both decreased.
B) The energy on the macroscopic scale increased, and the energy on the molecular scale decreased.
C) The energy on the macroscopic scale decreased, and the energy on the molecular scale increased.
D) The energy on the macroscopic scale and the energy on the molecular scale both remained constant.
If you have the rest please put them down :)
Answer:
Explanation:
C. The energy on the macroscopic scale decreased, and the energy on the molecular scale increased.
A. friction converts some energy on the macroscopic scale to energy on the molecular scale.
B. The mechanical energy of the system decreased because of friction.
B. The mechanical energy of the system at the beginning of the experiment is equal to the mechanical energy of the system at the end of the experiment.
B. the mechanical energy of the system decreased due to the transfer of energy on a macroscopic scale to energy on a molecular scale.
The ball rolling on the floor eventually comes to a stop which means that
the energy on the macroscopic scale decreased, and the energy on the
molecular scale increased.
What is Macroscopic scale?This is a scale in which an object can be seen with the eyes. When
an object is in motion, the ball rolls away and becomes less visible hence a
decrease in the macroscopic scale.
During motion, friction converts some macroscopic energy into molecular
scale which is why there was an increase in it.
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