Answer:
(a) The projectile takes approximately 4.420 seconds to reach the water, (b) The horizontal scope of the projectile is 1591.2 meters, (c) The remaining height to descend after 2 seconds of being launched is 63.624 meters.
Explanation:
The projectile experiments a parabolic motion, where horizontal speed remains constant and accelerates vertically due to the gravity effect. Let consider that drag can be neglected, so that kinematic equation are described below:
[tex]x = x_{o}+v_{o,x} \cdot t[/tex]
[tex]y = y_{o} + v_{o,y}\cdot t +\frac{1}{2}\cdot g \cdot t^{2}[/tex]
Where:
[tex]x_{o}[/tex], [tex]y_{o}[/tex] - Initial horizontal and vertical position of the projectile, measured in meters.
[tex]v_{o,x}[/tex], [tex]v_{o,y}[/tex] - Initial horizontal and vertical speed of the projectile, measured in meters per second.
[tex]t[/tex] - Time, measured in seconds.
[tex]g[/tex] - Gravitational acceleration, measured in meters per square second.
[tex]x[/tex], [tex]y[/tex] - Current horizontal and vertical position of the projectile, measured in meters.
Given that [tex]x_{o} = 0\,m[/tex], [tex]y_{o} = 80\,m[/tex], [tex]v_{o,x} = 360\,\frac{m}{s}[/tex], [tex]v_{o,y} = 0\,\frac{m}{s}[/tex] and [tex]g = -9.807\,\frac{m}{s^{2}}[/tex], the kinematic equations are, respectively:
[tex]x = 360\cdot t[/tex]
[tex]y = 80-4.094\cdot t^{2}[/tex]
(a) If [tex]y = 0\,m[/tex], the time taken for the projectile to reach the water is:
[tex]80 - 4.094\cdot t^{2} = 0[/tex]
[tex]t = \sqrt{\frac{80}{4.094} }\,s[/tex]
[tex]t \approx 4.420\,s[/tex]
The projectile takes approximately 4.420 seconds to reach the water.
(b) The horizontal scope is the horizontal distance done by the projectile before reaching the water. If [tex]t \approx 4.420\,s[/tex], the horizontal scope of the projectile is:
[tex]x = 360\cdot (4.420)[/tex]
[tex]x = 1591.2\,m[/tex]
The horizontal scope of the projectile is 1591.2 meters.
(c) If [tex]t = 2\,s[/tex], the height that remains to descend is:
[tex]y = 80-4.094\cdot (2)^{2}[/tex]
[tex]y = 63.624\,m[/tex]
The remaining height to descend after 2 seconds of being launched is 63.624 meters.
Determine whether or not each of the following statements is true. If a statement is true, prove it. If a statement is false, provide a counterexample and explain how it constitutes a counter-example.
A capacitor consists of two flat, metal plates with unequal areas. Each of the plates starts neutral, and then each plate is connected to a dierent terminal of a battery. After some time, the plates will have excess charge on them, and the magnitude of the excess charge on one plate will equal the magnitude of the excess charge on the other plate.
A. True
B. False
If a wire carries current, then it has a net non-zero charge in it.
A. True
B. False
Answer:
a) True b) True
Explanation:
a) a capacitor is made up of two flat plates and each one has a charge of the same sign, therefore the statement is true
b) the current is the flow of electrons per unit of time, therefore the charge is not zero, therefore the statement is True
Suppose the maximum safe intensity of microwaves for human exposure is taken to be 1.00 W/m2. (a) If a radar unit leaks 50.0 W of microwaves (other than those sent by its antenna) uniformly in all directions, how far away (in cm) must you be to be exposed to an intensity considered to be safe
Answer:
The safe distance is 199 cm approximately 200 cm
Explanation:
Safe intensity = 1.00 W/m^2
wattage of radar leaked radar = 50.0 W
safe distance from the microwave will be = ?
We know that the intensity of a wave radiated uniformly in all direction is given as
[tex]I[/tex] = [tex]\frac{W}{A}[/tex]
where
W is the wattage of the leaked radar
A is the radial area, which is the area of a sphere that encapsulates the region through which this wave spreads uniformly.
From the equation above,
[tex]A[/tex] = [tex]\frac{W}{I}[/tex] = 50/1 = 50 m^2
But the area of this sphere [tex]A[/tex] = [tex]4\pi r^{2}[/tex]
where
r is the safe distance from the radar source
substituting for the area, we have
50 = 4 x 3.142 x [tex]r^{2}[/tex]
50 = 12.568 [tex]r^{2}[/tex]
[tex]r^{2}[/tex] = 50/12.568 = 3.978
r = [tex]\sqrt{3.978}[/tex] = 1.99 m = 199 cm ≅ 200 cm
3. An electron with a mass of 9.11 X 10^-31 kg is moving at a speed of 2.19 X 10 m/s. What is the kinetic energy of the electron?
Answer:
[tex] 2.18\times 10^{-30} \:J[/tex]
Explanation:
[tex] K.E._{Electron}= \frac{1}{2} mv^2 \\\\
= \frac{1}{2} \times 9.11\times 10^{-31}\times (2.19\times 10)^2 \\\\
=4.555\times 10^{-31}\times 4.7961\times 10^2 \\\\
=4.555\times 10^{-31+2}\times 4.7961 \\\\
=21.8462355\times 10^{-29}\\
=2.18462355\times 10^{-30}\\
=2.18\times 10^{-30} \:J\\[/tex]
Thurst exerted by an object of area20m² experiencing pressure 150 Nm‐² is ________
Answer:
3000 N
Explanation:
as we know that
pressure=force/area
so force=thurst
pressure=thurst/area
thyrst=pressure*area
pressure=150 Nm^-2
area=20m^2
so thurst=150*20=3000 N or 3*10^3 N
Which force is there between an ice skate and the ice
2. A solid sphere and a solid cylinder, both uniform and of the same mass and radius, roll without slipping at the same forward speed. It is correct to say that the total kinetic energy of the solid sphere is A) more than the total kinetic energy of the cylinder. B) less than the total kinetic energy of the cylinder. C) equal to the total kinetic energy of the cylinder.
A polonium isotope with an atomic mass of 211.988868 u undergoes alpha decay, resulting in a daughter isotope with an atomic mass of 207.976652 u. Ignoring any recoil of the daughter, find the kinetic energy of the emitted alpha particle in megaelectronvolts (MeV).
Answer:
K = 9.53 MeV
Explanation:
The kinetic energy that the alpha particle has emitted, is the energy in excess after removing the resting energy of the atoms and the helium nucleus that forms the alpha particle
Since energy and masses are related and cannot be
m₀ c² = [tex]m_{f}[/tex] c² + m_He c²+ K
K = c² (m₀ - m_{f} - m_He)
the mass of the Helium atom is 4 u
K = (3 10⁸)² (211,988868 -207.976652 - 4,002) 1,661 10⁻²⁷
K = 14,949 10⁻¹¹ (0.0102)
K = 1,527 10⁻¹² J
let's reduce 1 J = 6,242 10¹² MeV
K = 9.53 MeV
(a) Two microwave frequencies are authorized for use in microwave ovens: 900 and 2560 MHz. Calculate the wavelength of each. (b) Which frequency would produce smaller hot spots in foods due to interference effects
Answer:
a) wavelength for the two frequencies are 0.33 m and 0.12 m
(b) 2560 MHz
Explanation:
Given:
microwave frequencies are
900 and 2560 MHz
f1= 900MHz we need to convert it to Go so the unit will be able to be consistent
f1= 900MHz= 900× 10^6Hz
f2= 2560 MHz= 2560×10^6Hz
a)Calculate the wavelength of each
But we can calculate our wavelength λ using the below formula
λ=c/f
c which is the speed of light has a constant value of =3*10^8m/s
Then for the first frequency
λ=c/f =(3×10^8)/900×10^6
=0.33 m
=33 cm.
For the second frequency
λ=c/f = (3×10^8)/2560×10^6
=0.12 m
=12 cm
(b) Which frequency would produce smaller hot spots in foods due to interference effects
(b) 2560 MHz( has the smallest wavelength)
This is because a small wavelength microwave gives a pattern with which is interference with waves and have a closer hotspot
Select the type of energy involved in each step. You turn on the burner of a gas stove. The gas ignites. The gas warms the water in the pan.
Answer:
You turn on the burner of a gas or stove - mechanical energy.
The gas ignites - Chemical energy.
The gas warms the water in the pan - Thermal energy.
Do you think, are we need to learn Measurement in Physics. Explain how the measurement is necessary and inevitable in real life situations?
Answer:
Measurement is inevitable because in every single thing we do we measure.for instance, if you are a family of four,the food prepared will be less than the food prepared for a family of about 15 people.this is measurement.if not so,the food prepared will go waste.again, the drugs prescribed by the doctor is measured to avoid over dose or under dose of medication.this can be harmful to ones health
Earthquakes at fault lines in Earth's crust create seismic waves, which are longitudinal (P-waves) or transverse (S-waves). The P-waves have a speed of about 9 km/s. Estimate the average bulk modulus of Earth's crust given that the density of rock is about 2500 kg/m3
Answer:
[tex]B=2.025\times 10^{11}\ Pa[/tex]
Explanation:
It is given that,
Speed of P- waves, v = 9 km/s = 9000 m/s
The density of rock is about [tex]2500\ kg/m^3[/tex]
We need to find the average bulk modulus of Earth's crust. Let it is given by B. So,
[tex]v=\sqrt{\dfrac{B}{d}} \\\\B=v^2d\\\\B=(9000)^2\times 2500\\\\B=2.025\times 10^{11}\ Pa[/tex]
So, the bulk modulus of the Earth's crust is [tex]2.025\times 10^{11}\ Pa[/tex].
A truck is moving with a certain uniform velocity. It is accelerated uniformly by 0.75 m/s^2. After 20 seconds , the velocity becomes 72km/h.Find the initial velocity
Answer:
Vi = 5 m/s
Explanation:
let (a) acceleration = 0.75 m/s²
(t) time = 20 seconds
Vf = final velocity = 72 km/hr (convert to m/s to units consistency = 20 m/s)
find Initial velocity (Vi)
Vf - Vi
a = -----------
t
Vi = Vf - (a * t) = 20 - (0.75 * 20)
Vi = 5 m/s
PLEASE HELP!!!! i will give brainliest to the first person...
Answer: Fossil fuels power the machine that shakes the tree so the apples fall to the ground
Explanation: most machines are powered by fossil fuels
A rocket is launched vertically from the ground with an initial velocity of 64. Write a quadratic function that shows the height, in feet, of the rocket t seconds after it was launched.
Answer:
y = 64t − 16t²
Explanation:
y = y₀ + v₀ t + ½ at²
y = 0 + 64 t + ½ (-32) t²
y = 64t − 16t²
A rocket moves through empty space in a straight line with constant speed. It is very far from any star or planet. Under these conditions, the force that must be applied to the rocket in order to sustain its motion is
Answer:
analysis the force is zero
Explanation:
Let's apply Newton's second law
F = m a
In this equation we see that the force is directly related to the acceleration, as they indicate that the rocket is far from any planet or star has no force applied to it, therefore they also relate it to zero.
Change we can analyze the exercise with Newton's first law, which indicates that an object maintains its constant speed in a straight line has no forces applied to it.
In either analysis the force is zero
5. i) Name two devices based on interaction between magnetic field and current carrying conductor.
Answer:
some common devices that use current carrying conductors and magnetic fields are electric motor electric generator loudspeakers microphones and measuring instruments like galvanometer ammeter and voltmeter
Signal propagation in the nervous system can be modeled as
a) A resistor network.
b) A wave of electricity that travels down conducting tissue.
c) A series of RC circuits.
Answer:
c) A series of RC circuits.
A boat floats in a lake. When the boat moves the force of resistance is proportional to the velocity of the boat. Initially the boat is at rest. A person walks from the stern to the bow of the boat. What will be the position of the boat long time after the person stopped moving?
Answer: Contant.
Explanation:
You are given that When the boat moves the force of resistance is proportional to the velocity of the boat. This means that the total momentum on the boat is equal to zero. Then the boat remains at a certain position.
When a person walks from the stern to the bow of the boat, the boat will tend to move in the opposite direction with equal magnitude of momentum. The magnitude of forces will thereby cancel out.
The person will be seen moving while the boat moves in the opposite direction.
If no external force is acting on the boat, the sum of the momentum of the person and the boat will be equal to zero. And the boat will remain at rest.
The position of the boat long time after the person stopped moving will therefore remain the same.
Una masa de 0,5 kg está sobre una pendiente inclinada 20º sujeta mediante una cuerda paralela a la pendiente que impide que deslice. Si no hay rozamiento, ¿qué fuerza hace la cuerda?
Answer:
4.61 N
Explanation:
masa = 0.5 kg
ángulo de inclinación = 20°
Peso normal de la masa = mg
donde m = masa
g = aceleración debido a la gravedad = 9.81 m/s^2
Peso normal = 0.5 x 9.81 = 4.905 N
Si la masa se mantiene en su lugar mediante una cuerda paralela al plano, y no hay fricción en la masa, entonces
La fuerza sobre la cuerda = peso normal x cos ∅
donde ∅ = 20 °
La fuerza sobre la cuerda = 4.905 x cos 20°
==> 4.61 N
Which of these are scientific questions? Check all that apply. How will climate change affect forests? Which planet is the prettiest? How did life on Earth begin? Why did dinosaurs go extinct? Which volcano is the most amazing?
Answer:
The scientific questions here are:
a) How will climate change affect forests
b) How did life on Earth begin
c) Why did dinosaurs go extinct
Explanation:
Scientific question are logical quantifiable questions, whose answers can be measured. A good scientific question must have answers that can be tested by a carefully designed experiment or measurement. Some qualities like "prettiest" and "amazing" cannot be tested for nor are they measurable, and hence, they do not make a testable component of good scientific question.
Q. A train accelerates from 36 km/h to 54 km/h in 10 sec. (i) Acceleration (ii) The distance travelled by car.
u=10m/s
v=15m/s
acceleration=
v_u/ t
5/10
0.5
You are observing the radiation from a distant active galaxy and you notice that the amplitude of the signal varies in strength regularly over a certain period. The maximum possible size for the source of this radiation can now be calculated from the:____________
Answer:
Period of the signal.
Explanation:
So, this question is all about a concept in physics or astronomy which is called or known as Radiation Astronomy and Galactic Nuclei that are active. This concept talks most about Quasars; a powerful radiating object which derives its power from black holes.
When You take a look at Quasars, we get the to know that the more you think you can see, the more they move away from us.
Thus, when "You are observing the radiation from a distant active galaxy and you notice that the amplitude of the signal varies in strength regularly over a certain period. The maximum possible size for the source of this radiation can now be calculated from the "PERIOD OF THE SIGNAL.
NB: not the amplitude but the period.
Two runners start at a distance of 10 miles from each other. They run towards each other at a constant velocity of 5 mph. A fly takes off from runner one’s nose at time zero. The fly has a constant velocity of 20 mph and flies between the runners. Find the total distance that the fly has traveled when the runners collide.
Answer:
The fly will travel 20 miles before the runners collide with each other.
Explanation:
Since the runners are both traveling at the same speed, they will meet and collide in the exact middle of each other which is 5 miles away from their starting point. Since they are traveling at 5 mph, it will take exactly one hour before they collide. The fly is going 20 mph so it will travel 20 miles before the runners collide in one hour.
If three cars, each of mass 1000 kg , occupy the NE, SE, and SW corners, determine the coordinates of the CM of the loaded ferryboat relative to the center of the raft. Take the origin to be at the CM of the raft.
Answer:
Using X = sum( x's * mass)/sum( masses)
= [(0)*(6400)+ (-9.5*1000) + (9.5)*(1000) + (9.5)*(1000)]/(6400+1000+1000+1000)
= 1.01 m
Y = sum( y's * mass)/sum( masses)
= [(0)*(6400) + (9.5)*(1000) +(-9.5)*(1000) + (-9.5)*(1000)]/ (6400+1000+1000+1000)
= -1.01 m
Which of the following is a TRUE
statement about states of matter?
A. Most matter on Earth exists as a solid, liquid, or gas.
B. Plasma, the fourth state of matter, is abundant on Earth.
C. Matter never changes from a solid to a liquid or a gas.
D. Most matter in the universe is liquid.
The statement that is the most true regarding the states of matter is the first statement.
A. Most matter on Earth exists as a solid, liquid, or gas.
This is correct since most of the matter on Earth exists in those 3 states, meanwhile plasma is not a state that most of matter on earth is found in since it is mostly associated to stars and the external galactic regions.
Therefore, B is incorrect.
C is false, since almost of all of the matter on earth can transform and change through each of the 3 states of matter, solid, liquid, and gas.
D is false since most of the matter in universe is actually made out of plasma instead of a liquid. In fact, over 99% of the known universe's matter is said to consist of plasma.
Matter can be defined as the material substance which constitutes the observable nature. Most matter on Earth exists as a solid, liquid, or gas. Plasma is also the state of matter found in daily life. The correct option is A.
What are states of matter?All the materials which we see in our daily lives are made up of matter. Matter can be classified into different states such as solid, liquid and gas based on the intermolecular forces and the arrangement of particles. All the three states of matter can be converted from one form to another.
The molecules of solid are tightly packed and they have strong intermolecular forces which also has a definite shape and volume. The liquids have weak intermolecular forces than the solids and it acquire the shape of the vessel.
The intermolecular forces in gases are negligible and they do not have any fixed shape or volume.
Thus the correct option is A.
To know more about states of matter, visit;
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A ball is thrown vertically upwards. It returns 6s later. Calculate : (1) the greatest height reached by the ball, and (2) the initial velocity of the ball. (Take g=9.8m/s2)
Answer:
greatest displacement = 44.1m
initial velocity= 29.4m/s
Explanation:
Greatest displacement
s=1/2at^2
= (9.8/2 ×9)m
= 44.1m
initial velocity
s=ut-1/2at^2
44.1= 3u -(1/2×9.8×9)
44.1=3u-44.1
3u=88.2
u=29.4m/s
The water tank is kept at some height of the buildings. Why?
Answer:
The water is at the top because when the water is stored at the top it does not need as much energy to get it to flow because it will be flowing down and be affected by gravity to make the water pressure.
Answer:
The water is at the top because when the water is stored at the top it does not need as much energy to get it to flow because it will be flowing down and be affected by gravity to make the water pressure.
Explanation:
4. Going back to the dog whistle in question 1, what is the minimum riding speed needed to be able to hear the whistle? Remember, you can assume the following things: The whistle you use to call your hunting dog has a frequency of 21.0 kHz, but your dog is ignoring it. You suspect the whistle may not be working, but you can't hear sounds above 20.0 kHz. The speed of sound is 330 m/s at the current air temperature.
Answer:
The minimum riding speed relative to the whistle (stationary) to be able to hear the sound at 21.0 kHz frequency is 15.7 m/s
Explanation:
The Doppler shift equation is given as follows;
[tex]f' = \dfrac{v - v_o}{v + v_s} \times f[/tex]
Where:
f' = Required observed frequency = 20.0 kHz
f = Real frequency = 21.0 kHz
v = Sound wave velocity = 330 m/s
[tex]v_o[/tex] = Observer velocity = X m/s
[tex]v_s[/tex] = Source velocity = 0 m/s (Assuming the source is stationary)
Which gives;
[tex]20 = \dfrac{330- v_o}{330+0} \times 21[/tex]
330 - [tex]v_o[/tex] = (20/21)*330
[tex]v_o[/tex] = 330 - (20/21)*330 = 15.7 m/s
The minimum riding speed relative to the whistle (stationary) to be able to hear the sound at 21.0 kHz frequency = 15.7 m/s.
In this video, we see that a _____ magnetic field can create an electric current. In this video, we see that a _____ magnetic field can create an electric current. Changing Perpendicular Strong Dipole
Answer:
The correct option is (a) "Changing".
Explanation:
If a coil is placed in the magnetic field, due to the change in its magnetic flux an emf will induce in it. EMF is like voltage. So, due to the induced emf and current is induced in it. Hence, we can say that changing the magnetic field can create an electric current.
On his fishing trip Justin rides in a boat 12 km south. The fish aren’t biting so they go 4 km west. They then follow a school of fish 1 km north. What distance did they cover? What was their displacement?
Answer:
I think the answer is 8km2
Answer:
Distance = 17km
Displacement = 12.6 km
Explanation:
south 12km
west 4km
north 1km
Total distance = 12 + 4 + 1 = 17km
Total displacement = in picture above.