Answer:
C. a few days
Explanation:
The evidence that we will have to investigate is the gunshot residue on the body of the suspect. When a person fires a gun there will be a deposition of material from the components of the chemicals present in the gun. This deposit is called gunshot residue and consists of particles of the propellant or explosive primer.
Experimentation has shown that the period of time that is person will test possible for gunshot residue is 5.27 days.
Answer:
A Few Hours
Explanation:
Residue on the hands can be difficult to find, even with modern forensic techniques. Part of the reason for this is that the residue doesn’t last for long on hands, particularly if the shooter washes, wipes, or rubs their hands. Studies indicate that even within hours of a shooting, it can be very difficult to find gunpowder residue on the hands of a shooter.
Please answer these questions
30 points
Answer:
if i were you i would try to do the work because if you let someone else you wont be able to understand the question
Hello There!
Where is fluid pressure greatest? "2 meters below the surface of a swimming pool."
#13 "the weight of the fluid displaced by the object"
#14 25 N•m
#15 "5"
99 POINTS
1.) Balance the following chemical equation: ___KOH + ___H₃PO₄ → ____K₃PO₄ + ___H₂O
2.) Balance the following chemical equation: ___Al(OH)₃ + ___HCl → ___AlCl₃ + ___H₂O
3.) Balance the following chemical equation: ___Fe₂O₃ + ___CO → ___CO₂ + ___Fe
4.) Balance the following chemical equation: ___AgI + ___Fe₂(CO₃)₃ → ___FeI₃ + ____Ag₂CO₃
There are four blanks on each and if there is no coefficient needed place a "1" in the blank
Answer:
Send a pic of it so i can mark it.
Explanation:
Fossils found in the La Brea tar pits indicate a California climate that was A) similar to today's climate. B) similar to the present-day tundra. C) desert-like, much drier and hotter than today. D) milder than today's climate, with high precipitation.
Answer:
A- similar to todays climate
Explanation:
I answer d and got it wrong
Fossils found in the La Brea tar pits indicate a California climate that was similar to today's climate. The correct option is A.
What is La Brea famous for?The La Brea Tar Pits is famous for the Fossils found in the Ice Ages,. The California climate still falls within our current climate.
California climate is like Mediterranean with somewhat like warm, dry summers with mild and wet winters. The average coastal temperature is around 70°F to 80°F.
Thus, fossils found in the La Brea tar pits indicate a California climate that was similar to today's climate. The correct option is A.
Learn more about La Brea.
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1)
Consider the four phases of matter. How do the characteristics of a liquid differ from a solid? All BUT ONE applies.
A) Energy has increased.
B) Temperature has increased..
C) Molecules begin to vibrate.
D) Intermolecular attraction decreased.
2)
The fourth state of matter, plasma, exists when what happens?
A) The atoms in a gas become ionized.
B) The atoms in a gas undergo nuclear fission.
C) The atoms in a gas lose all intermolecular attraction for one another.
D) When electromagnetic forces causes the atoms to stop colliding with one another.
Answer:
1) A, C, and D
2) D
Explanation:
1) In ice, for instance, the temperature decreases to become a solid, so B does not apply.
2) In most plasma's, the atoms don't collide into each other.
Answer:1 C
2 A
Explanation:
Liquids tend to gain more kinetic energy than solids. Energy is related with temperature. As the kinetic energy is increased so also is the temperature. This increase in temperature reduces the intermolecular attraction in solids.
Plasma comprise of positively Charged and negatively charged particles and occurs when the atoms in a gas becomes ionized.
The atomic number of a nucleus is the number of: A electrons B protons C neutrons D nucleons
Answer:
B protons
Explanation:
- The atomic number of a nucleus (often labelled with Z) is the number of protons inside the nucleus
- The mass number of a nucleus (often labelled with A) is the sum of the protons and the neutrons inside the nucleus
- The number of electrons in a neutral atom is equal to the number of protons inside the nucleus
Therefore, the correct answer is
B protons
However, A (electrons) could also be considered correct if we are talking about a neutral atom.
How does a nuclear power plant produce electricity?
Quickly moving neutrons coming out of nuclear reactions are used to turn turbines that produce electricity.
Quickly moving neutrons coming out of the reaction create a gas which turns a turbine that produces electricity.
Quickly moving neutrons give their kinetic energy to the surrounding water. The water's energy is then used to turn turbines and produce electricity.
Quickly moving neutrons coming out of the reaction are slowed down by water. The water heats up and turns into steam. The steam turns the turbine and produces electricity.
Answer: Quickly moving neutrons coming out of the reaction are slowed down by water. The water heats up and turns into steam. The steam turns the turbine and produces electricity.
Explanation: Hope that helps :D
The Answer is: D. Quickly moving neutrons coming out of the reaction are slowed down by water. The water heats up and turns into steam. The steam turns the turbine and produces electricity.
Acceleration can be found using a speed-time graph. Please select the best answer from the choices provided T F
Answer:
False
Explanation:
Acceleration is defined as the rate of change of velocity:
[tex]a=\frac{\Delta v}{\Delta t}[/tex]
On a speed-time graph, the slope of the curve gives the magnitude of the acceleration. In fact, the slope of the curve in a speed- time graph is
[tex]m=\frac{\Delta y}{\Delta x}[/tex]
where
[tex]\Delta y[/tex] is the increment in the y-variable, so it corresponds to the change in speed
[tex]\Delta x[/tex] is the increment in the x-variable, so it corresponds to the change in time
so the slope corresponds to
[tex]m=\frac{\Delta v}{\Delta t}[/tex]
which is the magnitude of the velocity. However, in order to define acceleration we need an additional piece of information: the direction. Since speed is a scalar, direction of motion is not provided, so we cannot fully define acceleration from a speed-time graph.
What is electrostatic force?
Answer:Physicists deal with the four fundamental forces, which are the gravitational force, weak nuclear force, strong nuclear force, and electromagnetic force. The electrostatic force is associated with the electromagnetic force. Here is the definition of electrostatic force, its history, and a look at how it's calculated
Explanation:
Answer:
Electrostatics is a branch of physics that studies electric charges at rest. Since classical physics, it has been known that some materials such as amber attract lightweight particles after rubbing.
Explanation:
Electrostatic forces are attractive or repulsive forces between particles that are caused by their electric charges. This force is also called the Coulomb force or Coulomb interaction. It is named for the French physicist Charles-Augustin de Coulomb, who described the force in 1795.
Which of the following is the best thermal conductor?
A. Wood
B. Copper
c. Plastic
D. Paper
The best thermal conductor is copper.
Thermal conductivity:Thermal conductivity is the measurment of materials ability to pass heat through it.
Materials with a higher thermal conductivity can effectively pass heat and easily take up heat from their environment.
Poor thermal conductors puts resistance to heat flow and take heat slowly from the surroundings.
The thermal conductivity can be measured in Watts per meter per degree Kelvin (W/m•K).
Copper thermal conductivity is 398 W/m•K which is more than wood, plastic and paper.
Therefore the correct answer is copper (option B)
To learn more thermal conductivity, refer:
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which of thWhich of the following is a true statement?
A. Electric fields increase in strength as you move farther from the charge, but electric forces decrease.
B. Both electric fields and forces decrease in strength as the distance increases.
C. Electric fields don't change in strength with distance from a charge, but electric forces do.
D. Electric forces stay the same as distance changes, but electric fields change.e following is a true statement
Answer:
B. Both electric fields and forces ...
Explanation:
Answer:
B. Both electric fields and forces decrease in strength as the distance increases.
Explanation:
from the Coulomb's law
[tex]F=\frac{k q_{1} q_{2} }{r^{2}}[/tex]
electrif field is also expressed as
F = qE., so
[tex]E = \frac{k q}{r^{2}}[/tex]
it can seen that electric force and electric field and dependent on distance. that is inverse square of distance.
so, if the electric force and eletric field decreases in strength, it is because the distance of separation has increased.
name three states of matter?
Hello!
There are actually four states of matter. The three main ones are solids, liquids and gasses. The fourth one is called plasma.
Solids have a definite shape and volume.
Liquids have a definite volume but not shape.
Gas doesn’t have a definite volume or shape.
Plasma is like gas but made of electricity charged particles and very hot.
A plane passes over point a with a velocity of 5000 m/s north. Sixty seconds later it passes over point b at a velocity of 10,000 m/s north. What is the plane’s acceleration from A to B?
Answer:
The plane’s acceleration from A to B is
[tex]a =83.33\ m/s^2[/tex]
Explanation:
The acceleration of an object is a measure of how its speed changes over time.
In this case, we know that the plane initially has a velocity of 5000 m/s when it passes through point A, and when it passes through point B, 60 seconds later it has a velocity of 10,000 m/s.
Then the average acceleration is calculated as
[tex]a =\frac{s_2-s_1}{t_2-t_1}[/tex]
Where
[tex]s_2 = 10 000[/tex] is the final speed
[tex]s_1=5000[/tex] is the initial velocity
[tex]t_2 -t_1=60[/tex] is the time it took for the object to reach the final speed
Then
[tex]a =\frac{10000-5000}{60}[/tex]
[tex]a =\frac{5000}{60}[/tex]
[tex]a =83.33\ m/s^2[/tex]
Copernicus's model of the universe differs from Ptolemy's because Copernicus believed
Answer:
That the Sun was the center of the universe.
Explanation:
Ptolemy believed in geocentrism, which means that the Earth is the center of the Universe. This was also supported by Aristotle. Copernicus on the other hand believed in a heliocentric system, which proposes that the sun is the center of the universe.
Answer:
Earth rotates on its axis and orbits the sun.
Explanation:
Ptolemy believed earth is stationary and is located at the center of the universe. Every celestial object moves around the earth.
It was easier to assume that the earth is not moving since it appears to be stationary to people dwelling on it and to assume that the celestial objects are actually rotating the earth since they appear to be moving.
This is the perfect example that looks can be deceiving. In the ancient times the circle is believed to be a divine shape since it is perfect and the two major celestial objects, the sun and the moon, moves in a circular path. But it turns out, not everything rotates the earth in circular orbit. So Ptolemy proposed nested circular orbits. Which was so complex and farfetched.
Copernicus, a student of Tycho Brahe, (remember Tycho Brahe is an advocate of geocentric theory) inherited Tycho brahe's records of the movements of mars. He could not explain the retrograde motion of mars within the limits of geocentric theory.
He then suggested to remove the concept of divinity, associated with the earth being the center of all universe and to treat earth like every other celestial object. He was the first ever radical who steered us on the right path. In his heliocentric theory, earth rotates on its axis and orbits the sun. This can explain the retrograde motion of mars very easily
A student wants to lift a 350 N bucket of water up from the bottom of a well using a wheel and axle. The wheel has a
radius of 55 cm, and the axle has a radius of 15 cm. How much force will the student need to provide to the wheel to
turn it and lift the bucket?
28.8 N
4242 N
1283 N
95.5 N
Final answer:
The student will need to provide a force of approximately 95.5 N to turn the wheel and lift the bucket of water.
Explanation:
To calculate the force the student needs to provide to the wheel, we can use the concept of mechanical advantage. The mechanical advantage of a wheel and axle is given by the ratio of the radius of the wheel to the radius of the axle. In this case, the mechanical advantage is:
MA = radius of wheel / radius of axle
MA = 55 cm / 15 cm
MA = 3.67
Therefore, the force the student needs to provide to the wheel is:
Force = 350 N / MA
Force = 350 N / 3.67
Force ≈ 95.5 N
Match each type of wave to the way it moves.
transverse wave
longitudinal wave
electromagnetic wave
back and forth at right angles to the direction of the motion of the wave
arrowRight
two alternating waves moving at right angles to each other
arrowRight
back and forth in the direction of the motion of the wave
arrowRight
Answer:
Transverse wave- Back and forth at right angles to the direction of the wave arrow.
longitudinal wave- bask and forth in the direction of the motion of the motion of the wave.
electromagnetic wave- two alternating waves moving at right angles to each other.
Explanation:
In a longitudinal wave, the particles vibrate at right angles in reference to the wave motion.
In a transverse wave, the particles vibrate parallel to the wave motion
Electromagnetic waves occur as a result of the interaction between two waves and are normally transverse in nature.
Answer:
Transverse wave ---> back and forth at right angles to the direction of the motion of the wave.
Electromagnetic wave ----> two alternating waves moving at right angles to each other.
Longitudinal wave ----> back and forth in the direction of the motion of the wave.
Explanation:
You turn on the faucet for your garden hose and let go immediately the end search flying around and spraying water everywhere which of newtons laws of motion does this motion represent
hi this is a two part question please help!
12. What is the net force on the box above? *
1 point
A. 10 N
B. 15 N
C. 25 N
D. 30 N
13. In which direction will the box from above move? *
1 point
A. Right
B. Left
C. It will not move.
Hi!
So I don't know what the heck net force is, but I think the box would move right because there is more force moving to the right.
A 300 kg cae traveling at 60-m/s rear ends a 600 kg truck plodding along at 10 m/s. The vehicles collide and bounce apart with the car moving forward at 15 m/s. What is the final velocity of the truck?
Answer:
32.5 m/s
Explanation:
The total momentum must be conserved before and after the collision:
[tex]p_i = p_f\\m_c u_c + m_t u_t = m_c v_c + m_t v_t[/tex]
where
m_c = 300 kg is the mass of the car
m_t = 600 kg is the mass of the truck
u_c = 60 m/s is the initial velocity of the car
u_t = 10 m/s is the initial velocity of the truck
v_c = 15 m/s is the final velocity of the car
v_f is the final velocity of the truck
Solving for v_f, we find:
[tex]v_f = \frac{m_c u_c + m_t u_t - m_c v_c}{m_t}=\frac{(300 kg)(60 m/s)+(600 kg)(10 m/s)-(300 kg)(15 m/s)}{600 kg}=32.5 m/s[/tex]
The graph below show how natural processes and human activities affect climate
Answer:here’s the graph d
Explanation:
Apex
the heat from the sun mainly comes by
Answer:
The Sun. The heat that eventually causes the earth to warm actually comes from the sun. The sun is a huge ball of gases, mainly hydrogen. Every day, the hydrogen in the sun is converted into helium through millions and millions of chemical reactions.
Does this help?
A train travels 600 km in 4 hours. What is the speed of the train?
Answer:
150 km/h
Explanation:
A speed measures a distance traveled over a period of time. We usually express speed in terms of km/h for example.
That train travels 600 km in 4 hours.
To find its average speed, we just need to divide 600 km / 4 hours
We then get 150 km/h
That's said to be the average speed since it's the total distance in the total of time.... it might have been slower or faster at different points during that distance/time.
In the formula C12H22011 how many atoms and elements are there?
Answer:
Explanation:
12 + 22 + 11 = 45
There are 45 atoms, and there are three elements: C, H, and O.
What is the gravitational force between two trucks, each with a masof 2.0x10^4 k
That are 2.0m apart
Answer:
[tex]6.67\cdot 10^{-3} N[/tex]
Explanation:
The gravitational force between two objects is given by
[tex]F=G\frac{m_1 m_2}{r^2}[/tex]
where
G is the gravitational constant
m1, m2 are the two masses
r is the separation between the two masses
In this problem, we have
[tex]m_1 = m_2 = 2.0 \cdot 10^4 kg[/tex] the mass of each truck
r = 2.0 m is their separation
Substituting,
[tex]F=(6.67\cdot 10^{-11}) \frac{(2.0\cdot 10^4 kg)^2}{(2.0 m)^2}=6.67\cdot 10^{-3} N[/tex]
The gravitational force between the two trucks is calculated using Newton's Universal Law of Gravitation. The force is very small due to the relatively small masses of the trucks compared to large bodies like the Earth.
Explanation:The gravitational force between the two trucks can be calculated using Newton's Universal Law of Gravitation. This law is given in the form F = G * (M1 * M2) / R², where F is the gravitational force, G is the gravitational constant (6.67 × 10^-11 Nm²/kg²), M1 and M2 are the masses of the two bodies in kilograms, and R is their separation in meters.
For the two trucks, the equation can be applied as follows: F = 6.67 × 10^-11 Nm²/kg² * ((2.0x10^4 kg) * (2.0x10^4 kg)) / (2.0 m)². This gives us the gravitational force that the two trucks exert on each other.
It is worth noting that while the gravitational forces between such small bodies are noticeable, they are extremely small. This is consistent with our everyday experience that we do not feel the gravitational force of other nearby objects, but only the force exerted by the Earth, which is of a much larger mass.
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In the following circuit, the supplied voltage is 1.5 volts and the resistor value is 2 ohms. Use Ohm's law to determine the current in the circuit.
3.0 amps
0.75 amps
3.5 amps
1.3 amps
Answer:
0.75 Amps
Explanation:
I had this question and this was right
Answer:
Current, I = 0.75 amps
Explanation:
Given that
Supplied voltage, V = 1.5 volts
Value of resistor, R = 2 ohms
Ohm's law to used to determine the current in the circuit. Mathematically, it is given by :
V = I R
I = current flowing in the circuit
[tex]I=\dfrac{V}{R}[/tex]
[tex]I=\dfrac{1.5\ V}{2\ ohms}[/tex]
I = 0.75 amps
So, the current flowing in the circuit is 0.75 amps. Hence, the correct option is (b) ''0.75 amps''.
A vase with a mass of 0.800 kilograms falls from a height of 0.750 meters to a position of 0.500 meters above the floor. Ignoring frictional effects, the total mechanical energy at the 0.500 position is _____.
Answer:
E= 2 J
Explanation:
For this case we see how the mechanical energy is generated by the potential energy due to the change of position. We can express that as
E=m*g*h
Being "m" the mass of the object, "g" the value of the acceleration by gravity and "h" the distance traveled in the movement. So
E=m*g*h=0.8Kg*10m/s2*(0.75-0.5)=2J
Done
A train of mass 320000 kg accelerate uniformly from rest. It takes 57 s to travel a distance of 810 m in a straight line. Find the average net force acting on the train.
Answer:
160,000 N
Explanation:
Given:
m = 320,000 kg
v₀ = 0 m/s
a = constant
t = 57 s
Δx = 810 m
Find: Fnet
Apply Newton's second law:
∑F = ma
Fnet = ma
To find Fnet, we must first find the acceleration.
x = x₀ + v₀ t + ½ at²
810 m = 0 m + (0 m/s) (57 s) + ½ a (57 s)²
a = 0.50 m/s²
Fnet = (320,000 kg) (0.50 m/s²)
Fnet = 160,000 N
The fundamental mode of vibration of a wave is defiened as that which as the lowest ____.
Answer:
Frequency
Explanation:
Answer:
Frequency
Explanation:
Solve the current and voltage problems for the ci
current and voltage problems for the circuit below using your knowledge of current and voltage trends in series and parallel.
Explanation:
Each resistor has a resistance of R.
In the first problem, each row of three resistors in series has a resistance or 3R.
A₂ = 4A, so the voltage drop across the rows is:
V = IR
V = (4)(3R)
V = 12R
The voltage drop equals the voltage gain (Kirchoff's voltage law). The battery has a voltage of 9V, so:
9 = 12R
R = 0.75 Ω
The three rows are in parallel with each other, so the total resistance is:
∑R = (1/(3R) + 1/(3R) + 1/(3R))⁻¹
∑R = R
∑R = 0.75 Ω
The current A₁ can be found with Ohm's law:
V = IR
9 = (A₁) (0.75)
A₁ = 12 A
Using Ohm's law to find V₁, V₂, and V₃:
V = IR
V₁ = (4)(0.75)
V₁ = 3V
V₂ = (4)(2×0.75)
V₂ = 6 V
V₃ = (4)(3×0.75)
V₃ = 9 V
In the second problem, all the resistors are in series. So the total resistance is:
∑R = 8R
The battery voltage is 16V, and A₂ = 6A. So using Ohm's law:
V = IR
16 = (6)(8R)
R = 1/3 Ω
Since there's only one loop, the current is the same at all points. So A₁ = A₂ = 6A.
Using Ohm's law to find each voltage:
V = IR
V₁ = (6)(1/3)
V₁ = 2V
V₂ = (6)(2×1/3)
V₂ = 4 V
V₃ = (6)(4×1/3)
V₃ = 8 V
V₄ = (6)(2×1/3)
V₄ = 4 V
For the circuit shown in the left side of the image, A₁=12A, V₁=3V, V₂=6V, and V₃=9V.
The voltage source is Vs = 3(3V) = 9V is connected in parallel to the three branches that each contain three equals light bulbs, the three branches are in parallel meaning that the voltage in each branch is 9V.
The current through one branch is A₂ = 4A, we can calculate the equivalent resistance in that branch using Ohm's Law:
Req = V/I, where I = A₂ = 4A
Req = 9V/4A = 2.25Ω
We can calculate the resistance in each light bulb, there are three light bulb in each branch that have a equivalent resistance of 2.25Ω, the light bulbs are in serie, so:
Req = R + R + R = 3R
The resistance of each light bulb is R = Req/3 = 2.25Ω/3 = 0.75Ω
To calculate V₁, using Ohm's Law:
V₁ = I R = (4A)(0.75Ω) = 3V
Then, the other branches are in parallel and it has the same amount of light bulbs and the same characteristics, each branch has a equivalent resistance of 2.25Ω, and each light bulb has a resistance of 0.75Ω.
To calculate V₂ and V₃:
We know that the voltage in each branch is 9V, each light bulb has a drop of voltage of 3V. So, the total voltage in one branch is the sum of each drop of voltage on each light bulb Vt = 3V + 3V + 3V = 9V.
V₂ = 3V + 3V = 6v
v₃ = Vt = 3V + 3V + 3V = 9V
To calculate the total current A₁ through the circuit, we know that the current through each branch is 4A, the total current A₁ is:
A₁ = 3A₂ = 3(4A) = 12A
For the circuit shown in the right side of the image, A₁=A₂=6A, V₁=2V, V₂=V₄=4V, and V₃=8V.
The voltage source is Vs = 4(-4V) = -16V connected in series with 8 light bulbs, the current flow through each light bulb, It= A₁ = A₂ = 6A. The voltage source is Vs= -16V, the '-' means that the current flows in the opposite direction.
To calculate the equivalent resistance of the circuit, using Ohm's Law:
Req = Vs/It = 16V/6A = 2.67Ω
The resistance of each light bulb is R = Req/8 = 2.67Ω/8 = 0.33Ω
The drop of voltage on each light bulb is:
V = It R = (6A)(0.33Ω) = 2V
V₁ = 2V
V₂ = V₄ = 2(2V) = 4V
V₃ = 4(2V) = 8V
HELP ASAP
In which scenario is thermal energy being transferred by radiation?
A) a lava lamp
B) a hot of coffee in he snow
C) baby chicks under a heat lamp
D) an iron ironing a shirt
Answer:
C) baby chicks under a heat lamp
Explanation:
The heat transfer by radiation is observed in the case that some chicks are heating with a heat lamp since heat is transmitted without contact between the surfaces
In the case of ironing the shirt, the transfer is made by the contact of the iron with the shirt. In the case of the lava lamp, the most important transfer is that of light energy, and in the case of coffee in the snow, when the coffee cup is placed in the snow, the heat will also be transferred by the contact of the surfaces
Answer:
The answer is C.)
Explanation:
I hope this helps :)
A mover hoists a 50 kg box from the ground to a height of 2 m. What was the change in the box's energy
Answer:
980 J
Explanation:
The change in box's energy is equal to its change in gravitational potential energy:
[tex]\Delta U = m g \Delta h[/tex]
where
m = 50 kg is the mass of the box
g = 9.8 m/s^2 is the acceleration due to gravity
[tex]\Delta h= 2m[/tex] is the change in height of the box
Substituting numbers, we find
[tex]\Delta U = (50 kg)(9.8 m/s^2)(2 m)=980 J[/tex]
Answer:
This is late, but your answer would be 1,000 J
Explanation:
How I got my answer was I used the Gravitational Potential Energy Calculator on the calculator soup. the answer I got when I plugged 50 and 2 into the calculator is 980, but since it's not on the list of choices, I went with the closest one, 1,000 J
I got it correct on my test; here is the proof