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.
Problem
When a piece of aluminum is
placed in a 25 ml
graduated
cylinder that contains 10.5mL of water, the water level rises to 13.5m. What is the mass of
the aluminum?
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!!!
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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Calculate the efficiency of an engine if the work input is 300. J and the work output is 100. J
Answer:
33.33%
Explanation:
take efficiency =power output/power input multiply by 100%
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]
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
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?
Where is earth's magnetic north pole located?
Answer: it is located over Ellesmere Island, Canada
Explanation
it is now drifting away from North America and toward Siberia.
Answer:ellesmere island, Canada
A point charge (5.0 pC) is located at the center of a spherical surface (radius = 2.0 cm), and a charge of 3.0 pC is spread uniformly upon this surface. Determine the magnitude of the electric field 1.0 cm from the point charge.
Answer:
E = 0.45 kN/C
Explanation:
From; the question, we can opine that the electric field inside the hollow sphere as a result of the charge at the surface is zero.
Using the equation:
[tex]\mathbf{E = kq/r^2}[/tex] to determine the magnitude of the electric field with the radius 1.0 cm from the point charge.
where ;
constant k = [tex]8.98*10^9[/tex]
point charge q = 5.0 pC = 5.0 × 10⁻¹²; we have :
[tex]\mathbf{E = kq/r^2}[/tex]
[tex]\mathbf{E =\dfrac{8.98*10^9*5*10^{-12}}{1.0^2}}[/tex]
E = 0.45 kN/C
Question 2
A wave with a frequency of 10 Hz and a wavelength of 4 m would have what speed?
m/s
Answer:
speed = 40 m/s
Explanation:
speed = frequency x wavelength
speed = 10 Hz x 4 m
speed = 40 m/s
The RMS potential difference of an AC household outlet is 117 V. a) What is the maximum potential difference across a lamp connected to the outlet? b) If the RMS current through the lamp is 5.5 A, what is the lam
Answer:
a. 165.5 V
b. 7.78 A
Explanation:
Here is the complete question
The RMS potential difference of an AC household outlet is 117 V. a) What is the maximum potential difference across a lamp connected to the outlet? b) If the RMS current through the lamp is 5.5 A, what is the maximun current through the lamp.
Solution
a. The maximum potential difference across the lamp V₀ = √2V₁ where V₁ = rms value of potential difference = 117 V
V₀ = √2V₁ = √2 × 117 V = 165.5 V
b. The maximum current through the lamp I₀ = √2I₁ where I₁ = rms value of current = 5.5 A
V₀ = √2V₁ = √2 × 5.5 A = 7.78 A
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
Caleb conduce su motocicleta por con una velocidad constante de 38 km/h y luego por otras 2 horas con una velocidad constante de 20 km/h. ¿Cuál es su velocidad media para el viaje total?
Answer:
No Lo se :v esque estoy enferma del
Culovirus :v ༎ຶ‿༎ຶ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
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:
Why can chemical energy and nuclear energy be considered a potential energy
Answer:
because it is due the Intrecation between sub atomic particles
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
Filiberto va a 90m/s en su carri, de repente se distrae por un par de segundos y su velocdad pasa a 40 m/s ¿cual fue su aceleracion de su movimientonto
Answer:
Filiberto experimenta una deceleración de [tex]2\,\frac{m}{s^{2}}[/tex].
Explanation:
(The problem was written in Spanish. Hence, explanation will be held in Spanish).
Asúmase que Filiberto se distrae por 2 segundos, puesto que un par equivale a dos, y que el vehículo experimenta un aceleración constante. La deceleración experimentada por el vehículo se deriva de la siguiente fórmula:
[tex]a = \frac{v-v_{o}}{\Delta t}[/tex]
[tex]a = \frac{40\,\frac{m}{s}-90\,\frac{m}{s} }{2\,s}[/tex]
[tex]a = -25\,\frac{m}{s^{2}}[/tex]
Filiberto experimenta una deceleración de [tex]2\,\frac{m}{s^{2}}[/tex].
what is electrostatic force all about?
Explanation:
the electrostatic force is also known as the coulomb force or coulomb interaction. it's the attractive or repulsive force between two electrically charged object. like charges repel each other while unlike charges attract each other. coulomb's law is used to calculate the strength of the force between two charger .
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
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).
How do air quality scientists ensure the air is cleaned? What steps do they take?
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
You accidentally drop a book down a stairwell. Assuming no air resistance,
how fast will the book be moving after 0.75 seconds?
Answer:
if we drop it and not throw it then
after 0.75 how fast the book is falling is given by its velocity as
v= at
= 9.8 × 0.75
=7.35 m/s
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]
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
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
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
How long will it take you to drive the 256 miles to get to the Mackinac Island Ferry if you average 70 mi/hr? If you leave at 3:00, what time will you get there? *Using speed formula
Answer:
If the speed is 70 mile/hour, the time to drive the 256 miles is:
T = 256/70 = 3.66 hours = 3 hours and 39.6 minutes
If you leave at 3:00, then at 6 hours and 39.6 minutes, you will get there.
Hope this helps!
:)