Answer:
It's all about Gravity. When parachutists jump and open the parachute, the parachute increases the air resistance due to which acceleration due to gravity decreases, thus parachutists land safely without getting hurt.
Se lanza desde el piso una piedra con velocidad vertical de +42 m/s. El punto de referencia se encuentra en el piso. Calcular: a). Escribir la ecuación de posición y la ecuación de la velocidad. b). Calcular en que instante su velocidad es nula. c). Calcular la máxima altura que llego. (Considerar la aceleración de la gravedad: a=9.81m/s2).
Answer:
a) y = 42 t - 4,905 t² , v = 42 - 9.81 t, b) t = 4.281 s , c) y = 89.9 m
Explanation:
This problem is an example of vertical launch
a) the expression for the position is
y = v₀ t - ½ g t²
we substitute
y = 42 t - 4,905 t²
the expression for speed is
v = v₀ - gt
v = 42 - 9.81 t
b) the speed is null when v = 0
v₀ = gt
t = v₀ / g
t = 42 / 9.81
t = 4.281 s
c) for the maximum height we can use the expression
v² = v₀² - 2gy
at maximum height v = 0
y = v₀² / 2g
let's calculate
y = 42 2/2 9.81
y = 89.9 m
Why can chemical energy and nuclear energy be considered a potential energy
Answer:
because it is due the Intrecation between sub atomic particles
A person of mass 55 kg swings on a rope length 4 m from rest (when the rope makes an angle of 30 degrees with the vertical) and collides perfectly inelastically with a 70 kg person on the ground when the rope is exactly vertical. Determine the maximum angle the rope makes with the vertical after the 55 kg person picks up the 70 kg person.
Answer:
θ = 19.66°
Explanation:
To determine the angle that the rope makes with the vertical for the two people, you first take into account the potential energy of the first person before he swings on the rope:
[tex]U=mgh[/tex]
h: distance to the ground
g: gravitational acceleration = 9.8m/s^2
m: mass of the first person = 55 kg
In the image attache below you can notice that the height h is:
[tex]h=4-4cos(30\°)=0.53m[/tex]
Then, the potential energy is:
[tex]U=(55kg)(9.8m/s^2)(0.53m)=285.67J[/tex]
When the first person picks up the second person (when the rope is exactly vertical), all the potential energy becomes kinetic energy. Next, when both people reaches the maximum height h' the energy must be equal to the initial potential energy of the first person:
[tex]U'=(m_1+m_2)gh'=285.67\ J[/tex]
From the previous equation you can get h':
[tex]h'=\frac{285.67J}{(55kg+70kg)(9.8m/s^2)}=0.2332m[/tex]
Finally, you obtain the angle between the rope at the height h,' and the vertical, by calculating the following:
[tex]h'=4-4cos(\theta)\\\\\theta=cos^{-1}(\frac{4-h'}{4})=cos^{-1}(\frac{4-0.2332}{4})=19.66\°[/tex]
hence, the angle between the rope and the vertical, when the two people are in the rope is 19.66°
El tiempo de reacción de un conductor de automóvil es 0,75s. Si el automóvil puede experimentar una desaceleracion de 4m/s^2. Calcular la distancia recorrida hasta detenerse una vez recibida la señal, cuando su velocidad era 10m/s
Answer:
x_total = 20m
Explanation:
This is an exercise in kinematics, we will look for the distance it travels during the reaction time, where there is no braking, and then the distance during the deceleration.
Distance traveled during response time
v = x₁ / t
x₁ = v t
let's calculate
x₁ = 10 0.75
x₁ = 7.5 m
Now we calculate the distance during braking, the final speed is zero (v = 0)
v² = v₀² - 2 a x₂
x₂ = v₀² / 2 a
let's calculate
x₂ = 10² / (2 4)
x₂ = 12.5m
the total stopping distance is
x_total = x₁ + x₂
X_total = 7.5 + 12.5
x_total = 20m
What other forensic techniques have come under fire as not being as scientific as presumed?
Answer:
Explanation:
Forensic techniques such as bite mark analysis, blood spatter analysis, ballistic analysis, the matching of bullet casings to a gun, the matching of hair and fibers, and fingerprint analysis. All of these have come under fire which have not being as scientific as presumed.
A 0.10 newton spring toy with a spring constant of 160 newtons per meter is compressed 0.05 meter before it is launched. When released the spring toy pops up and reaches a maximum height of 1.5 meters.
1) How much elastic potential energy is initially stored in the spring?
2)How much internal energy is produced as the toy springs up to its maximum height?
Answer:
(1) V = 0.2 J (2) 0.05J
Explanation:
Solution
Given that:
K = 160 N/m
x = 0.05 m
Now,
(1) we solve for the initial potential energy stored
Thus,
V = 1/2 kx² = 0.5 * 160 * (0.05)²
Therefore V = 0.2 J
(2)Now, we solve for how much of the internal energy is produced as the toy springs up to its maximum height.
By using the energy conversion, we have the following
ΔV = mgh
=(0.1/9.8) * 9.8 * 1.5 = 0.15J
The internal energy = 0.2 -0.15
=0.05J
A radio wave has a frequency of 5.5 × 104 hertz and travels at a speed of 3.0 × 108 meters/second. What is its wavelength?
Answer:5.45X10^3m
Explanation:So use the formula,v= fλ
3X10^8=5.5X10^4λ what Im saying is divide both and u should get 5454.54m but do sig figs to get answer
Answer:
5.45X10^3m
Explanation:
17.
What type of energy wave is highest in energy? (3 points)
Radio wave
Microwave
Visible light
Gamma wave
Answer:
gamma waves
Explanation:
gamma rays" from lightning discharges at 10 to 20 MeV, and known to be produced by the bremsstrahlung mechanism. Another example is gamma-ray bursts, now known to be produced from processes too powerful to involve simple collections of atoms undergoing radioactive decay.
The current in the wires of a circuit is 60.0 milliAmps. If the voltage impressed across the ends of the circuit were one-third of the original voltage (with no change in its resistance), then its new current would be _____ milliAmps. *
Answer: its mile 10 it has to be not this one
Explanation: to be load
You're sitting on a warm granite rock, enjoying the sunshine. You decide it's time to test the water. You take off your shoes and walk across the cool sand to the water. You wade into the water, enough to cover your feet. Brrr! The water is cold. You will have to wear a dry suit when you go diving.
a. Which item - the granite rock, the sand, or the water - has the highest specific heat? Which has the lowest specific heat?
b. Which item requires the least energy to increase its temperature? Explain your answer in terms of this item's specific heat.
c. If the granite rock on which you were sitting has a specific heat of 600 J/(kg°C), how much energy must be added to a 2-kilogram piece of it to increase its temperature from 20°C to 30°C? Show your work, including the equation you need to perform this calculation.
d. What is the second law of thermodynamics? Use this law to describe why your feet got cold, not hot, when you put them in the water.
Answer: seen below
Explanation:
a) Water has the highest specific heat capacity in this case while sand has the lowest specific heat capacity.
b) Sand absorb the least energy for it temperature change (increase or decrease). This means that their temperatures change more quickly due to it low specific heat capacity of 0.290J/g°C) at 25°C)
c) using the formula:
Q = m × cP × (final temperature -initial temperature)
where:
Q = heat
m = is the mass
cP = is the mass heat capacity,
T= is the temperature
Q = 2 kg × 600 J/(kg°C) × (30°C - 20°C)
Q = 12000 J
d) in simpler term, The second law of thermodynamics states that when energy changes from one form to another form, entropy The second law of thermodynamics says that when energy changes from one form to another form, or matter moves freely, entropy (which is a measure of the amount of energy in a physical system that cannot be used to do work) in a closed system increases. This is why your feet gets cold when you put them in the water.
The space shuttle approaches earth at a speed of 2.89*10^4 km/h when it sends a radio signal to earth 1.00*10^5 km away. The radio signal will reach earth in ____ seconds
Answer:
3 secods later
Explanation:
How do air quality scientists ensure the air is cleaned? What steps do they take?
Can someone help me out??? I need this done ASAP TYSM!!
Answer:
Answer is D
Explanation:
By changing the direction of the current moving through the wire will change polarity of the magnet but it will not affect the strength of the magnet.
explain how you would measure the volume of irregular shaped object using the displacement method
Answer:
Place the object in the graduated cylinder, and record the resulting water volume as "b." Subtract the volume of the water alone from the volume of the water plus the object. For instance, if "b" was 50 milliliters and "a" was 25 milliliters, the volume of the irregularly shaped object would be 25 milliliters.
The volume of the irregular solid can be measured using a graduated cylinder having a known volume of water.
A solid is irregular if it does not fit into any of the known shapes. It is possible to determine the volume of these objects using the displacement method.
In this method, a graduated cylinder containing a known volume of water is used. The irregular solid is now introduced into the cylinder and the displacement of the water is noted.
The displacement of the water is obtained as;
Final volume of water - Initial volume of water. The amount of water displaced is equal to the volume of the irregular solid.
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i really need help !!
Answer:
The generator will work only if the magnetic field associated with the turns of coil change.
here both magnet and coil are stationary with respect to each other so no electromagnetic induction would take place. so no indiced current will be produced.
the student has to introduce some mechanism either to rotate the coil or the magnet
If a 0.5 kg ball is thrown up with 250 J of kinetic energy, how high will it go?
(HINT: At the ball's highest point it has stopped.)
KE = 1/2mv2
G = 9.8 m/s2
Answer:
51.02m
Explanation:
KE = 1/2mv2
Where k.e = 250J
mass = 0.5 kg
g = 9.8 m/s2
250= 1/2×0.5×v^2
250= 0.5×0.5×v^2
250= 0.25v^2
v^2 = 250/0.25
v^2 = 1000
v =√1000
v = 31.62m/s
v^2= u^2-2gh........... (1)
Since the object will stop at it highest point, hence it final velocity there will be zero and since it is moving up against the gravity g= -9.8m/s^2. That was why the formula in equation 1 has a negative sign
From h = u^2/2g
Where v = 31.62m/s
g = 9.8m/s^2
H = (31.62m/s)^2/9.8×2
H= 1000/19.6
= 51.02m
Hence the height of it travelling will be
51.02m
El piloto de un contenedor parte de la ciudad de Guatemala a las 8:00 AM hacia Puerto Barrios, Izabal, debiendo recorrer 310 km sobre la carretera hasta llegar a la entrada del puerto donde debe entregar el contenedor a las 12:00 del mediodía. Calcule la rapidez promedio a la que deberá conducir el piloto para poderlo entregar a tiempo. Si el piloto sabe de antemano que debe detenerse una hora para hacer cola en el Progreso, por la ampliación de la carretera, calcule cuál debería ser entonces la rapidez promedio a la que debe conducir. ¿Medite si será posible o razonable que un contenedor viaje por la carretera a esa rapidez? Si la distancia en línea recta desde la ciudad de Guatemala hasta Puerto Barrios es de 250 km. ¿Cuál es la longitud de la trayectoria del contenedor? ¿Cuál fue su desplazamiento?
A car with a crashtest dummy inside travels at 40.23 m/s (90 mph) toward a stone wall during a crash test. When it strikes the wall, the car takes 0.70 s to stop. Calculate the deceleration of the car.
Answer:
The answer is [tex]-57.47m/s^{2}[/tex]Explanation:
In the question we are to solve for the deceleration of the car on impact.Given data
[tex]speed= 40.23m/s\\[/tex]
[tex]time[/tex] =[tex]0.70second[/tex]
To determine the deceleration we apply,
[tex]acceleration = \frac{speed}{time} \\\\acceleration= \frac{40.23}{0.7}[/tex]
[tex]acceleration = -57.47m/s^{2}[/tex]
what should police remove to study the physical conditions of a gun homicide case?
the victims clothes
any valuables from the victim (wallet, jewelry)
the victims cell phone
the victims dentures, if they wear any
Answer:
Explanation:
the victims cell phone
A concave mirror has a radius of curvature of 0.60 meter.
When an object is placed 0.40 meter from the reflecting
surface, the image distance will be
0.10 m
0.20 m
0.83 m
o 1.2 m
PLEASE HELP WILL GIVE BRANLIEST, EXTRA POINTS!
Jailah needs a replacement for lithium for a science experiment. She tries silicon, but it does not work. Using what you know about patterns in the periodic table, which advice would you give Jailah?
A. Try a lanthanide series element.
B. Try a non-metal from the halogen group.
C. Try an element in the same group as lithium.
D. Try an element in the same period as lithium.
Answer:
C. Try an element in the same group as lithium.
Explanation:
Answer:
The answer is C.
Explanation:
I'm took the test on it
You are pushing a box up a ramp with 70 N of force. If the ramp is made steeper and shorter, what needs to happen to the box for it to continue moving?
Answer:
A larger force than 70 N will be required for the box to continue moving
Explanation:
A ramp is an inclined plane surface that is tilted to form a slope on its opposite sides
A ramp provides mechanical advantage or force amplification, by allowing less force to lift heavier load from having to move through a longer distance to reach a particular elevation when the slope of the ramp is gentle
Therefore, when the slope is steeper, and shorter, more force than 70 N will be required for the box to continue moving.
Answer:
your force needs to increase to more than 70 N
Explanation:
plato
A small object begins a free-fall from a height of =81.5 m at 0=0 s . After τ=2.20 s , a second small object is launched vertically up from the ground with an initial velocity of 0=40.0 m/s . At what height from the ground will the two objects first meet?
Answer:
33.23 m
Explanation:
At the point where both objects will meet, the vertical height will be equal.
From the equations of motion, the vertical height of the body falling at any time is given as
(y - y₀) = ut + ½gt²
y = vertical height at any time T
y₀ = initial height of the object = 81.5 m
u = initial velocity = 0 m/s (body was dropped)
g = -9.8 m/s²
(y - 81.5) = 0 - 4.9T²
y = 81.5 - 4.9T² (eqn 1)
For an object thrown up, the vertical height of the body at any time, t, is given as
(y - y₀) = ut + ½gt²
y = vertical height of the object at any time t
y₀ = initial height of the object = 0 m
u = initial velocity = 40 m/s
g = -9.8 m/s²
y = 40t - 4.9t² (eqn 2)
At the point where the two objects meet, we equate eqn 1 and eqn 2
y = y
81.5 - 4.9T² = 40t - 4.9t²
But T = (t + 2.2) (Since object 2 was dropped 2.2 s after object 1)
81.5 - 4.9(t + 2.2)² = 40t - 4.9t²
81.5 - 4.9(t² + 4.4t + 4.84) = 40t - 4.9t²
81.5 - 4.9t² - 21.56t - 23.716 = 40t - 4.9t²
81.5 - 21.56t - 23.716 - 40t = 0
57.784 = 61.56t
t = (57.784/61.56) = 0.93866 = 0.94 s
Therefore, the vertical height at t = 0.93866 s is
y = (40×0.93866) - 4.9(0.93866²) = 33.23 m
Hope this Helps!!!
Un tren de pasajeros viaja a razon de 36km/hrs al ingresar a un tunel de 200m de longitud demora 50seg en salir de el .¿cuanto es la longitud del tren?
Answer:
[tex]\Delta L = 300\,m[/tex]
Explanation:
La longitud del tren se deriva de la siguiente fórmula (The length of the train is derived from the following formula):
[tex]\Delta L + 200\,m = v\cdot \Delta t[/tex]
[tex]\Delta L = \left(36\,\frac{km}{h} \right)\cdot \left(1000\,\frac{m}{km} \right)\cdot \left(\frac{1}{3600}\,\frac{h}{s} \right)\cdot (50\,s) - 200\,m[/tex]
La longitud del tren es (The length of the train is):
[tex]\Delta L = 300\,m[/tex]
Select the correct answer.
Which is a transverse wave that requires a medium to move?
A.
ocean wave
B.
sound wave
C.
light wave
D.
microwave
Answer:
a
Explanation:
¿Alguien me puede ayudar? Problema: Un niño le pide gastada a su papá y éste le contesta que le dará los $120 que tiene en su bolsillo siempre y cuando conteste cuántas monedas de a $5 y de a $2 tiene en él si en total hay 33. ¿Qué debe contestar el niño si quiere los $120?
Answer: there are 15 coins of $2 and 18 coins of $5
Explanation:
I will answer in English.
X is the number of $5 coins.
Y is the number of $2 coins.
We have the system of equations:
Y + X = 33
Y*2 + X*5 = 120
first, we must isolate one of the variables in one of the equations and then replace it in the other equation, let's isolate Y in the first equation:
Y = 33 - X.
Then we can replace it in the other equation:
(33 - X)*2 + X*5 = 120
66 - X*2 + X*5 = 120
X*3 = 54
X = 54/3 = 18
and using the equation for Y.
Y = 33 - X = 33 - 18 = 15
So there are 15 coins of $2 and 18 coins of $5
If a car accelerates uniformly from rest to 15 meters
per second over a distance of 100 meters, the magnitude of the car’s acceleration is
Answer:
1.125 m/s²
Explanation:
Applying Newton's equation of motion,
v² = u²+2as
Where v = final velocity, u = initial velocity, a = acceleration, s = distance.
Note: u = 0 m/s ( from rest)
make a the subject of the equation above.
a = v²/2s................ Equation 2
Given: v = 15 m/s². s = 100 m
Substitute into equation 2
a = 15²/(2×100)
a = 225/200
a = 1.125 m/s²
The magnitude of the car's acceleration is 1.125 m/s²
The calculation can be as follows;
u= 0
v= 15m/s
s= 100 meters
The formular is
v²= u² + 2as
15² = 0² + 2(a)(100)
225= 200a
a= 225/200
a= 1.125
Hence the initial velocity is 1.125 m/s²
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Which statement below best describes the relationship between the voltage, resistance, and current?
Group of answer choices
A.) As voltage increases, current increases and resistance stays the same
B.) As voltage decreases, current and resistance stay the same
C.) As voltage decreases, current and resistance both increase
D.) As voltage increases, current and resistance both decrease
Answer:
As voltage increases, current increases and resistance stays the same .
Explanation:
Ohm's law gives the relationship between the voltage, resistance, and current. The mathematical form of Ohm's law is given by :
[tex]V\propto I\\\\V=IR[/tex]
R is resistance
I is current
V is voltage
So, as voltage increases, current increases and resistance stays the same. The correct option is (A).
What is a lunar month
Answer:
It's the duration between successive new moons. Also called a lunation or synodic month, it has a mean period of 29.53059 days (29 days 12 hours and 44 minutes).
The speed of light in a material is 0.50
c. what is the critical angle of a light ray at the interface between the material and a vacuum?
Answer:
Explanation:
This problem indicates that the speed of light in a material medium is 0.5 10⁸ m / s, they ask to find the critical angle between the material and the vacuum
Let's find the refractive index of the material
n = c / v
n = 3 10⁸ / 0.5 10⁸
n = 6
When the material passes from one medium to another, it must comply with the law of refraction
n₁ sin θ = n₂ sin θ₂
for the angle criticize the angles tea2 = 90
tea = sin⁻¹n₂/ n₁
The vacuum replacement index is n₂ = 1
tea = sin⁻¹ (1/6)
tea = 9.59º
Answer:
30 degrees
Explanation: First, what is the critical angle? Critical angle is the angle from the normal, at which light enters another medium, which causes the reflected light to reflect at an angle of 90 degrees.
Using Snell's Law:
critical angle = sin^-1(n2/n1)
n2 = c/v. In a vacuum this = 1
n1 = c/.5c = 2
critical angle = sin^-1(1/2)=30 degrees