What is the wavelength of a radio photon from an "AM" radio station that broadcasts at 1520 kilohertz? And what is its energy?
Given parameters:
Frequency of the wave = 1520kHz = 1520 x 10³Hz
Unknown:
Wavelength of the radio photon = ?
Energy of the wave = ?
Solution:
The wavelength of any electromagnetic wave can found using the expression below;
C = f x ∧
Where C is the velocity of light = 3 x 10⁸m/s
f is the frequency of the wave
∧ is the wavelength
Since the unknown is ∧, input the known parameters and solve for it;
3 x 10⁸ = 1520 x 10³ x ∧
Wavelength = [tex]\frac{3 x 10^{8} }{1520 x 10^{3} }[/tex]
Wavelength = [tex]\frac{3 x 10^{8} }{1.52 x 10^{6} }[/tex]
Wavelength = 1.97 x 10²m
ii. Energy of the wave;
Energy of a wave = hf
where h is the planck's constant = 6.63 x 10⁻³⁴ J Hz⁻¹
f is the frequency of the wave
Input the parameters and solve;
Energy of the wave = 6.63 x 10⁻³⁴ x 1.52 x 10⁶
= 10.1 x 10⁻²⁸J
The energy of this wave is 10.1 x 10⁻²⁸J
Wavelength of the wave = 1.97 x 10²m
Energy of the wave = 10.1 x 10⁻²⁸J
Given:
Frequency of the wave = 1520kHz = 1520 x 10³Hz
To find:
Wavelength of the radio photon = ?
Energy of the wave = ?
Calculation of Wavelength:The wavelength of any electromagnetic wave can found using the expression below:
c = f * ∧
Where,
c is the velocity of light = 3 x 10⁸m/s
f is the frequency of the wave
∧ is the wavelength
On substituting the values:
3 x 10⁸ = 1520 x 10³ x ∧
Wavelength = 1.97 x 10²m
Calculation of Energy of the wave:Energy of a wave = h*f
where,
h is the Planck's constant = 6.63 x 10⁻³⁴ J Hz⁻¹
f is the frequency of the wave
On substituting the values:
Energy of the wave = 6.63 x 10⁻³⁴ x 1.52 x 10⁶
Energy of the wave = 10.1 x 10⁻²⁸J
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Water at the top of Horseshoe Falls (part of Niagara Falls)
is moving horizontally at 9.0 m/s as it goes off the edge and
plunges 53 m to the pool below. If you ignore air resistance,
at what angle is the falling water moving as it enters the
pool?
Answer:
[tex]\theta= (-74.42)^{\circ} C[/tex]
Explanation:
Horizontal speed of water, [tex]v_{xf}=9\ m/s[/tex]
Height, h = -53 (below pool)
We can find firstly the final vertical speed of the water using third equation of kinematics. So
[tex]v^2_{yf}=u^2_{yi}+2(-g)h\\\\v^2_{yf}=2\times -9.8\times -53\\\\v_{yf}=32.23\ m/s[/tex]
Let [tex]\theta[/tex] is the angle where the falling water moving as it enters the pool. So,
[tex]\tan\theta=\dfrac{v_{yf}}{v_{xf}}\\\\=\dfrac{-32.3}{9}\\\\=-74.42^{\circ} C[/tex]
Hence, the angle is (-74.42)°C.
Six insulated containers hold 3,750 g of water at 24°C. A small copper cylinder is placed in each container; the masses and initial temperatures of the cylinders vary as given below. Rank the containers according to the maximum temperature of the water in each container after the cylinder is added, from largest to smallest. You may assume that the cylinder is completely submerged in the water.A. m = 250 g; T = 30°CB. m = 500 g; T = 60°CC. m = 750 g; T = 90°CD. m = 500 g; T = 15°CE. m = 750 g; T = 30°CF. m = 250 g; T = 60°C
Answer:
the order from highest to lowest is C> B> F> E> A> D
Explanation:
This is an exercise in calorimetry where the heat given off by the copper cylinder is equal to the heat absorbed by the water
Q_c = m_Cu ce_Cu ΔT_Cu
Q_a = m_water Ce_water ΔT
Q_c = Q_a
m_Cu ce_Cu (T_o-T_f) = m_water ce_water (T_f - T_i)
we clear the final temperature and substitute the values
With this expression we can know the final temperature of the system, let's substitute the values that are constant throughout the calculation
With this expression we can know the final temperature of the system, let's substitute the values that are constant throughout the calculation
a) m = 0.250kg, To = 30ºC
T_{fa}=(387 0.250 30 + 376740) / (15697.5 + 387 0.250)
T_{fa}= 379642.5 / 15794.25
T_{f} = 24.04ºC
b) m = 0.500 kg, To = 60ºC
T_{fb} = (387 0.500 60 + 376740) / (15697.5 + 387 0.500)
T_{fb} = 388350/15891
T_{fb = 24.44 ° C
c) m = 0.750 kg, To = 90ºC
T_{fc}= (387 0.750 90 + 376740) / (15697.5 + 387 0.750)
T_{fc}= 402862.5 / 15987.75
T_{fc} = 25.20ºC
d) m = 0.500 kg, To = 15ºC
T_{fd} = (387 0.500 15 + 376740) / (15679.5 + 387 0.500)
T_{fd} = 379642.5 / 15891
T_{fd} = 23.89ºC
the order from highest to lowest is C> B> F> E> A> D
A physics student stands on a bathroom scale in an elevator which is not moving. The scale reads 604 N. The elevator then accelerates downward at 1.98 m/s2. What does the scale read during this acceleration?
Answer:
If we take downwards as the positive direction -
m a = m g - T difference between scale and mg is equal to acceleration
T = m (g - a)
m = 604 / 9.80 = 61.6 kg mass of student
T = 61.6 (9.80 - 1.98) = 482 N scale reading
The force when the elevator then accelerates downward at 1.98 m/s² is 725.78 N.
When the lift is stationary (at rest), the student is subject to a downward force equal to 604 N, which is caused by gravity (assumed to be equal to the student's weight according to the scale).
Given:
Force, F = 604 N
Acceleration, a = 1.98 m/s²
The mass can be computed from force and acceleration due to gravity
F = mg
604 N = mass × 9.81
mass = 604 N / 9.81
mass = 61.56 kg
The force is calculated as:
F' = ma
F' = 61.56 kg × 1.98
F' = 121.78 N
The total force is :
Total force = F +F"
Total force = 604 N + 121.78 N
Total force = 725.78 N
Hence, the force when the elevator then accelerates downward at 1.98 m/s² is 725.78 N.
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You skip north for 12 minutes to your best friend's house that is 1.5 kilometers away. What is your average velocity?
Answer:
The average velocity is 7.5 km/h
Explanation:
Let's convert minutes to hours so our answer can be given in a common units of km/hour:
12 minutes = 12/60 hours = 0.2 hours
Now we estimate the average velocity calculating the distance travelled over the time it took:
1.5 / 0.2 km/h = 7.5 km/h
A particle is projected vertically upwards with a velocity of 34.3 m/s. For how long is the particle at a height of 49 m and above the point of projection?
Calculate the time to reach a height of 49 m:
S = V0 t - 1/2 g t^2
S = 34.3 t - 1/2 * 9.8 * t^2
4.9 t^2 - 34.3 t + 49 = 0
I get t = 2 and t = 5 as solutions of the quadratic.
We know that it takes v / a = 34.3 / 9.8 = 3.5 sec to reach maximum height.
So we have:
2 sec to reach 49 m
3.5 sec to reach max height
1.5 sec from 49 m to max height
1.5 sec from max height back down to 49 m
2 sec to fall from 49 m to ground
2 sec + 1.5 sec + 1.5 sec = 5 sec to go from ground to max height and back down to 49 m
What is the average speed of a car that travels 100 m over 10 s?
Answer: 10m per second.
Explanation: 100/10 is 10/1, so it would be 10m per second.
The passenger in a moving bus falls forward suddenly explain
Answer:
the kinetic energy force made the not to stay in a position if the person is not careful
A bar magnet is held vertically with its upper end a little bit below the center of a horizontal metal ring. The upper end of the magnet is its north pole, as shown in the figure. The bar magnet is now dropped. An observer views the ring from above its center. To this observer, how will the induced current in the ring behave as the magnet falls?.
Answer:
The current will flow counter-clockwise and be decreasing
Explanation:
A cave diver enters a long underwater tunnel, when her displacement with respect to the entry point is 20m,she accidentally drops her camera but she doesn't notice it missing until she is some 6m farther into the tunnel.She swims back 10m but cannot find the camera,so she decides to end the dive.How far from the entry point is she?Taking the positive direction out of the tunnel,what is her displacement vector relative to the entry point?
Answer:
3x864/y488bjehdksuwiieirjr
A scientist wants to know if adults prefer watching movies in a theater or in their home. He interviews 500 people leaving a local movie theater and finds that 480 of them like watching movies in theaters. The scientist concludes that 96 percent of people like watching movies in theaters more than at home. Why is the scientist's conclusion most likely unreliable?
Not enough people were interviewed.
The investigation was based on preferences.
The investigation was not replicable.
The location of the survey introduced bias
Answer:
The location of the survey is biased.
Explanation:
If someone left a movie theater, it is most likely because he likes watching movies there. A better place to interview would be on the streets, as it’s less biased there
Answer:
It will be D/ The location of the survey introduced bias!
Explanation:
A student moves a horseshoe magnet by hand across a tabletop to varying distances from an electromagnet, as shown in the diagram above.
The student records observations of how much force it takes to hold the horseshoe magnet in place at each distance. Observations
• 20 cm: no force required
• 10 cm: small force required; easy to hold in place
• 5 cm: large force required; very difficult to hold in place
What do the student's observations demonstrate?
A. The electromagnet's magnetic field becomes stronger as more magnetic material is added to it.
B. The electromagnet's magnetic field is stronger as more turns are added to the wire on the nail.
C. The electromagnet's magnetic field becomes stronger as a small amount of strength is added to the system by the battery.
D. The electromagnet's magnetic field is stronger close to it than far from it.
The closer together they are the harder it is to hold on to because the magnetic field is stronger as it gets closer.
Answer:
D. The electromagnet's magnetic field is stronger close to it than far from it.
IP A tow rope, parallel to the water, pulls a water skier directly behind the boat with constant velocity for a distance of 75 m before the skier falls. The tension in the rope is 100 N.
Is the work done on the skier by the rope positive, negative, or zero?
Explain.
Calculate the work done by the rope on the skier.
The work is done against the skier, we call it negative work, and the magnitude of the work done on the skier by the rope is 7500 J.
Work done on the skier
The work done on the skier by the rope is in opposte direction of the water skier which caused the water skier to fall after some given period of time. Since the work is done against the skier, we call it negative work.
The magnitude of the work done on the skier by the rope is calculated as follows;
W = Fd
where;
F is the applied force on the rope
d is the distance moved by the skier
W = 100 x 75
W = 7500 J
Thus, the magnitude of the work done on the skier by the rope is 7500 J.
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An Atwood machine that consists of two blocks mass (m1,m2) tied together with a massless rope that passes over a fixed pulley.If m1=m2=m. Determine the acceleration of the block of mass m2. Suppose,m1→[infinity],while m2 remains finite.What value does the magnitude of the tension approach.
Answer:
a = 0 m/s²
T = 2m₂g
Explanation:
In this scenario of a pulley with two masses hanging vertically over it, the formula of acceleration is given as follows:
a = g(m₁ - m₂)/(m₁ + m₂)
It is given that: m₁ = m₂ = m
Therefore,
a = g(m - m)/(m + m)
a = g(0)/(2m)
a = 0 m/s²
The tension of the rope in such case is given by the following formula:
T = 2m₁m₂g/(m₁ + m₂)
It is given that: m₁ = ∞
Therefore,
T = 2(∞)m₂g/(∞ + m₂)
T = ∞(2m₂g)/∞(1 + m₂/∞)
T = 2m₂g/(1 + 0)
T = 2m₂g
Several masses m are determined to be equal by comparing them on an equal-arm balance, and a large mass M is found to just balance two of the small ones on a similar balance. The mass M and one of the masses m are each forced to go around a bend of 1.0 m at a constant speed of 1.0 m/s. As they move around the curve their magnitudes of the forces acting on them are
Question 1 options:
a)
equal.
b)
in the ratio of 4:1.
c)
along the direction of motion.
d)
in the ratio of 2:1.
e)
zero.
Answer:
Option (d) is correct.
Explanation:
As the large mass M is found to just balance two of the small mass, m, so
[tex]M=2m\cdots(i)[/tex]
As both the masses M as well as m are forced to go around a bend of 1.0 m at a constant speed of 1.0 m/s.
So, the radius of curvature of the bend (curved path), R= 1.0 m
The speed both the masses, v= 1.0 m/s.
Naturally, without any restriction, all the masses have the tendency to move in a straight line due to its inertia, but here both the masses are moving on the curved path because of the application of the external force on them. This continuous change in the direction is due to the force by the wall of the curved path which is actually the normal reaction by the wall on both the masses.
This reaction force, [tex]F_R[/tex], balance the centrifugal force, F with which the masses have a tendency to go out of the path, the magnitude of this centrifugal force is,
[tex]F = \frac {mv^2}{R}[/tex]
Where m is the mass of the body, v is the speed at that instant, R is the radius of curvature of the path.
So, [tex]F_R=\frac {mv^2}{R}[/tex]
Now, for the small mass, m, the reaction force on it is
[tex]F_R1= \frac {mv^2}{R}[/tex]
[tex]\Rightarrow F_R1= \frac {m(1)^2}{1}[/tex]
[tex]\Rightarrow F_R1= m \cdots(ii)[/tex]
And for the bigger mass, M, the reaction force on it is
[tex]F_R2= \frac {Mv^2}{R}[/tex]
[tex]\Rightarrow F_R2= \frac {M(1)^2}{1}[/tex]
[tex]\Rightarrow F_R2= M[/tex]
By using equation (i), we have
[tex]F_R2= 2m[/tex]
[tex]\Rightarrow F_R2=2F_R1[/tex] [by using (ii)]
[tex]\Rightarrow F_R2 / F_R1 = 2/1[/tex]
So, the ratio of force acting on the bigger mass M to the magnitude of the force acting on the smaller mas m is 2:1.
Hence, option (d) is correct.
Which of the following is a poor conductor?
metal
Quarters
Ob
O
Od
C
wood
iron
Two objects have a gravitational force between them of 750N. The two objects now move towards
each other, the gravitational force between them
a. remains at 750N
b. increases above 750N
C. decreases below 750N
Answer:
b. increases above 750N
Explanation:
Okay
How do you support adolescent development?
Answer:
Adolescent Development
Adolescence is the period of transition between childhood and adulthood. Children who are entering adolescence are going through many changes. This article offers advice for adolescents and parents to negotiate these changes.
Answer:
How do you support adolescent development?
Explanation:
Parents are a key support for teens during this time of growth and reflection. Be aware of the stages of emotional development, and provide clear guidance at each phase. Acknowledge when to give space and independence to teens. Help guide teens to feel good about themselves.
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Where can you find the neutrons of an atom? in the nucleus with the protons orbiting the nucleus In the nucleus with the electrons this is not part of an atom
ANSWER PLEASE ITS A EXAM 10 POINTS PLEASE FASTTTTTTTTTTT!!!!!!!1
Answer:
Nuclease is the answer I know
I hope this is the answer
Jonny is pushing a 50-kg large package along the dorm room floor with 150 N force. Both the direction of push and the floor are horizontal. While he is pushing the package, it moves in a straight line with constant 0.6 m/s speed. Please ignore air-resistance and make sure to justify your answers to the questions below.
a) (10 points) Write down as much information as you can about the main horizontal forces exerted on the package (names, directions, and if enough information is given, numerical values).
b) (10 points) Write down as much information as you can about the main vertical forces exerted on the package (names, directions, and whenever possible, if enough information is given, numerical values).
c) (5 points) How far did the package move during 3 seconds of pushing? Explain
d) (5 points) What was the package’s acceleration during that time? Explain
2
a. The push is 150 N and acts to the right while the frictional force is 150 N and acts to the left.
b. The weight is 490 N and acts downwards while the normal force is 490 N and acts upwards.
c. The package moves 1.8 m
d. The package's acceleration is 0 m/s²
a. The horizontal forcesThe push is 150 N and acts to the right while the frictional force is 150 N and acts to the left.a
Since the direction of push and the floor is horizontal, and first horizontal force acting on the package is the push and its magnitude is 150 N.
Also, a frictional force also acts to oppose the motion of the package.
Since the packge moves at a constant velocity of 0.6 m/s, its acceleration is zero and thus the net force on the package is zero.
Let
F = push force and f = frictional forceSo, F - f = 0
F = f
= 150 N
So, the frictional force is 150 N and opposite to the push.
So, the push is 150 N and acts to the right while the frictional force is 150 N and acts to the left.
b Vertical forces on package
The weight is 490 N and acts downwards while the normal force is 490 N and acts upwards.
Since the floor is horizontal, the vertical forces that act on the package are its weight and the normal force due to the ground.
The direction of the weight is downwards while the direction of the normal force is upwards.
Since the floor is horizontal and the package does not move in the vertical direction, the net vertical force is zero.
Let W = weight of package = mg where m = mass of package = 50 kg and g = acceleration due to gravity = 9.8 m/s² and N = normal forceSo, the net force N - W = 0
N = W
= mg
= 50 kg × 9.8 m/s²
= 490 N
So, the weight is 490 N and acts downwards while the normal force is 490 N and acts upwards.
c. Distance package moves
The package moves 1.8 m
Since distance, d = vt where
v = velocity = 0.6 m/s and t = time = 3 sSo, d = vt
= 0.6 m/s × 3 s
= 1.8 m
So, the package moves 1.8 m
d. The package's acceleration
The package's acceleration is 0 m/s²
Since the net force on the package is zero, its acceleration is also zero. Since force, F = ma where
m = mass of package and a = acceleration of packageSince F = 0,
ma = 0
a = 0
So, the package's acceleration is 0 m/s²
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In a two-slit experiment, the slit separation is 3.00 × 10-5 m. The interference pattern is created on a screen that is 2.00 m away from the slits. If the 7th bright fringe on the screen is a linear distance of 10.0 cm away from the central fringe, what is the wavelength of the light? In a two-slit experiment, the slit separation is 3.00 × 10-5 m. The interference pattern is created on a screen that is 2.00 m away from the slits. If the 7th bright fringe on the screen is a linear distance of 10.0 cm away from the central fringe, what is the wavelength of the light? 214 nm 224 nm 204 nm 100 nm 234 nm
Answer:
The correct option is a: 214 nm.
Explanation:
The wavelength (λ) of the light can be calculated as follows:
[tex] \lambda = \frac{yd}{nD} [/tex] (1)
Where:
y: is the distance of the 7th bright fringe on the screen from the central fringe = 10.0 cm
d: is the distance between the slits = 3.00x10⁻⁵ m
D: is the distance between the screen and the slits = 2.00 m
n = 7
By entering all the above values into equation (1) we have:
[tex] \lambda = \frac{yd}{nD} = \frac{0.10 m*3.00 \cdot 10^{-5} m}{7*2.00 m} = 214.3 nm [/tex]
Therefore, the correct option is a: 214 nm.
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A drone flies 8 m/s due East with respects to the wind. The wind is blowing 6 m/s due North with respects to the ground. What is the speed of the drone with repeat to the ground?
A. 14m/s
B. 10m/s
C. 2m/s
D. 20m/s
Answer:
B. 10m/s
Explanation:
If a drone flies 8 m/s due East with respects to the wind and the wind is blowing 6 m/s due North, the speed of the drone with respect to the ground is its displacement.
Displacement is calculated using Pythagoras theorem.
d² = 8²+6²
d² = 64+36
d² = 100
Square root both sides
√d² = √100
d = 10m/s
Hence the distance of the drone with respect to the ground is 10m/s
Option B is correct
if an arrow is aimed at 45.0 angle and needs to land 90.4 m away how fast should it be fired?
The arrow should be fired with an initial speed of approximately 31.2 m/s to land 90.4 meters away when aimed at a 45.0-degree angle.
To calculate the initial speed required for an arrow fired at a 45.0-degree angle to land 90.4 meters away, we can utilize the principles of projectile motion.
In projectile motion, the horizontal and vertical components of motion are independent. We can break down the initial velocity into its horizontal and vertical components.
Angle of projection (θ) = 45.0 degrees
Range (horizontal distance) (R) = 90.4 meters
We can start by finding the horizontal component of the initial velocity (Vx) using the formula:
Vx = V * cos(θ)
Where V is the initial velocity.
Since the angle is 45.0 degrees, the cosine of 45.0 degrees is equal to 1 / √2.
Vx = V / √2
Next, we can find the vertical component of the initial velocity (Vy) using the formula:
Vy = V * sin(θ)
Again, since the angle is 45.0 degrees, the sine of 45.0 degrees is equal to 1 / √2.
Vy = V / √2
To determine the initial speed required, we need to consider the time of flight (T) for the arrow to reach the range. The time of flight can be calculated using the formula:
T = (2 * Vy) / g
Where g is the acceleration due to gravity (approximately 9.8 m/s^2).
Once we have the time of flight, we can calculate the horizontal component of the initial velocity (Vx) using the formula:
Vx = R / T
Now, we can substitute the expressions for Vx and Vy into the original equation:
Vx = V / √2
Vx = R / T
Solving for V:
V = Vx * √2
V = (R / T) * √2
Plugging in the given values of R and T:
V = (90.4 m / T) * √2
Finally, substituting the value of T:
V = (90.4 m / [(2 * Vy) / g]) * √2
Simplifying further:
V = (90.4 m * g * √2) / (2 * Vy)
V = (90.4 m * 9.8 m/s^2 * √2) / (2 * (V / √2))
V = (90.4 m * 9.8 m/s^2) / V
Squaring both sides:
V^2 = (90.4 m * 9.8 m/s^2) / V
Rearranging the equation:
V^3 = 90.4 m * 9.8 m/s^2
Taking the cube root of both sides:
V = ∛(90.4 m * 9.8 m/s^2)
Using a calculator, the final answer is:
V ≈ 31.2 m/s
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explain how warm air temperatures affect the density of the air
Explanation:
As the molecules heat and move faster, they are moving apart. So air, like most other substances, expands when heated and contracts when cooled. Because there is more space between the molecules, the air is less dense than the surrounding matter and the hot air floats upward.
The bonds of the products store 22 kJ more energy than the bonds of the
reactants. How is energy conserved during this reaction?
O A. The reaction system absorbs 22 kJ of energy from the
surroundings.
O B. The reaction creates 22 kJ of energy when bonds form.
O C. The surroundings absorb 22 kJ of energy from the reaction
system.
D. The reaction uses up 22 kJ of energy when bonds break.
Answer:A.
Explanation: The reaction system absorbs 22kJ of energy form the surroundings
Answer: The reaction system absorbs 22 kJ of energy from the
surroundings.
Explanation: I took the test.
The GPE for a 45 KG person at the top of a 2m slide
Answer:
22.5 J
Explanation:
GPE=wxh- 45kg divided by 2m= 22.5
Brain injuries can be caused by strong linear acceleration of the head. Imaging measurements of a human head upon impact show that the magnitude of displacement of the brain relative to the skull is, at most, approximately 1 mm, independent of the magnitude of the acceleration. Studies indicate that the probability of mild traumatic brain injury (MTBI) is approximately 25% for linear accelerations of the head of 50g, where g is the acceleration due to gravity (g = 9.8 m s 2 ). The probability of MTBI is ≈100% for linear accelerations of 150g. For this problem, model the case of a bicycle accident as a human head falling straight down from rest at a height of 2 meters. Assume the ground is very hard and does not compress upon impact. Also assume constant deceleration of the brain upon impact.(a) For the case when the cyclist is not wearing a helmet, what is the deceleration that the cyclist’s head undergoes upon contact with the ground? Express your answer in g’s. What is the probability of suffering a MTBI?(b) Suppose you want to design a helmet that reduces the probability of MTBI to less than 25%. By how much must the helmet compress after impact to achieve this goal for our model assumptions? Express your answer in cm. Do typical bicycle helmets provide this amount of compression?(c) Discuss ways in which our model (a human head falling straight down from rest at a height of approximately two meters onto an incompressible surface) could overor under-estimate the probability of MTBI in a bicycle accident.
Answer:
a) a = 2000 g , b) y = 4 cm
Explanation:
a) We can solve this part using the free fall relations
Let's start by finding the speed with which it reaches the ground, just before it starts to decelerate
v₁² = v₀² + 2 g y
as it comes out of rest the initial velocity is v₀ = 0
v₁ = √ 2g y
v₁ = √ (2 9.8 2)
v₁ = 6.26 m / s
in the braking part the distance is y₂ = 1 mm = 0.001 m
v² = v₁² - 2 a y₂
when stopping its velocity is zero v = 0
a = v₁² / 2y₂
a = 6.26² / (2 0.001)
a = 1.96 10⁴ m / s²
This is the braking acceleration.
Let's look for its relationship with the acceleration of gravity
a / g = 1.96 10⁴ / 9.8
a / g = 2000
a = 2000 g
b) to reduce the injury to less than 25%, the maximum acceleration that must be a = 50g = 490 m / s²
Let's find the distance it must travel to have this acceleration
v² = v₁² - 2 a y
y = (0 + v₁²) / 2a
y = 6.26² / (2 490)
y = 0.04 m
y = 4 cm
therefore we must have a helmet that deforms 4 cm before the head stops
Most bicycle helmets provide this protection since they are quite elongated
c) The main error in the calculations is not taking into account the
resistance with the air, in this sense the speed would be less than the calculated one and our calculations would be over estimated.
The second factor is that in a fall there may be an initial velocity different from zero, so the velocity would be higher and the acceleration as well, in this case our calculations are underestimated.
1 Figure 13.17 shows the screen of an oscilloscope. The time-base of the oscilloscope is set at 500 us div?.
Calculate the time period of the signal and hence its frequency.
Answer:
Explanation:
Time-base of the oscilloscope is set at 500 [tex]\mu s[/tex]/div. It means, one block in horizontal direction represents 500 microseconds. The period of the wave is the time to complete one oscillation and in the picture there is two-block for complete one oscillation, so the period and oscillation are:
[tex]T=(2)(500) =100 \mu s \rightarrow f=\frac{1}{T}=\frac{1}{100 \times 10^{-6}}=10000 Hz[/tex]
the time period of the signal is 1200μs and hence its frequency is 833 Hz
What is oscilloscope ?An oscilloscope is a sort of electronic test tool that shows fluctuating electrical voltages visually as a two-dimensional plot of one or more signals as a function of time. The primary goals are to display repeating or single waveforms on the screen that would otherwise occur too quickly for the human eye to discern. The exhibited waveform may then be analysed for amplitude, frequency, rising time, time interval, distortion, and other features. Previously, these values were calculated by manually measuring the waveform against the scales incorporated into the instrument's screen. Modern digital equipment may immediately compute and show these parameters.
Given,
Time knob = 500 μs/div
wavelength of wave in oscilloscope = 2.4 div
Period of time of the wave is 2.4 div×500 μs/div = 1200μs
frequency of the wave is 1/T = 1/12μs = 833 Hz
To know more about frequency :
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What is bought from an electric company
Answer: electricity
Explanation:
A well substantiated explanation, or, a group of common ideas intended to
explain something. *
O Inference
Theory
Hypothesis
Inertia