Newton's law of cooling states that the temperature of an object changes at a rate proportional to the difference between its temperature and that of its surroundings. Suppose that the temperature of a cup of coffee obeys Newton's law of cooling. If the coffee has a temperature of 185 degrees Fahrenheit when freshly poured, and 3 minutes later has cooled to 172 degrees in a room at 78 degrees, determine when the coffee reaches a temperature of 147 degrees.
Answer:
6.77 minutes
Explanation:
172 degree - 78 degree = (185 degree - 78 degree)e−2 k
=> 94 = 107
e−2 k => 94 ÷ 107
k => ln (94÷107) / 2
147 - 78 = (185 - 78)e ^[ln (94÷107) / 2]
=> 69 = 107 e^ [ln (94÷107) / 2]
e^[ln (94÷107) / 2] =69 ÷ 107
=> t = [ln (69 ÷ 107)] ÷ [ln (94÷107) / 2]
t=> -0.4387 ÷ -0.0648
t => 6.77 minutes.
Therefore, the final answer to the question is 6.77 minutes.
A bowl of ice cream is sitting on a table.
Which is NOT conduction?
A. The sunlight streaming through the window melts the
ice cream.
B. The bowl is cold because of the ice cream.
C. The table is cold because of the cold bowl.
Answer: The bowl is cold because of the ice cream
Explanation:
When dry ice appears to be smoking what is actually happening
Answer:
The “smoke” coming from dry ice is actually carbon dioxide gas, which is turning from a solid into a gas.
Explanation:
can someone help me with science:
The cells within a multicellular organism are of a uniform shape.
True
or False
Answer:
trur
Explanation:
gvidttcyhjddgdhjfjdjsjs
What is the equation for Hookes law ?
Answer:
Fs = -kx is the formula
Explanation:
Fs = spring force
k = spring constant
x = spring compression
Answer:
Equation of Hooks law
F=kx
Where,
F=Force applied
k= spring constant
x=extension of spring
Imagine you are a crime scene investigator. You are called to investigate a crime scene in a wooded area where a missing person’s body is discovered. When you arrive at the scene, you find that the body is located near a rocky area where the footing in unstable. You also notice that the victim has a large head wound. A particular medium size rock near the body has dried blood on it. Also, a water bottle lies ten feet away from the victim. Write a paragraph about how you would carry out the search for evidence. What evidence would you collect from the crime scene?
Answer:
First I would look for fingerprints on the rock and the water bottle than I would look for footprints and DNA (blood) from the murderer.
Thats aall I could think of ;-;
Answer:
Explanation:
Since the crime scene is located in a wooded area, I would request several more investigators to do a search of the area. These investigators have to spread out to do a line pattern search. While looking for evidence, I would first determine whether the body was moved. I would look for marks on the ground that would suggest that the body was dragged to where it was found. I would collect fingerprint evidence from the water bottle to determine if it was the victim’s or if another person was with the victim. I would also take samples from the clothing to determine if there is any trace evidence, such as hair, foreign fibers, or skin cells. I would collect several rocks from the area, including one with blood on it, as evidence. They would help me determine if the blood-covered rock had been moved, or if it had been used as a weapon.
A population pyramid is created by
graphing the distribution of ages in a population
Explanation:
Belive me if you dont then dont use the answer
Answer:
a graph that shows the distribution of ages across a population
recall that a centripetal force is not a new type of force: it's a role that is taken by one of the four types of force that we already use. if we see an object moving in a curved path, we know that at least one of those forces is pointing inward, acting centripetally. describe at least one real-life example of an object moving in a curved path where its centripetal force is provided at least partially by each of the following types of forces: gravity, normal force, tension,
Answer:
Answer in explanation.
Explanation:
GRAVITY AS CENTRIPETAL FORCE:
When a satellite orbits around a planet, it is in a circular motion. In this scenario, the centripetal force is provided by the gravity force.
NORMAL FORCE AS CENTRIPETAL FORCE:
When a spacecraft is sent into space, it rotates about its own axis to create artificial gravity. During this rotating motion, the centripetal force is provided by the normal reaction (force) of the walls of the satellite.
TENSION AS CENTRIPETAL FORCE:
When a mass attached to a rope is swirled in a circular motion, the tension in rope acts as the centripetal force.
Momentum is the ability to do work. true or false
Answer:
true
Explanation:
A 3.0-kg and a 1.0-kg box rest side-by-side on a smooth, level floor. A horizontal force of 32 N is applied to the 1.0-kg box pushing it against the 3.0-kg box, and, as a result, both boxes slide along the floor. How hard do the two boxes push against each other
Considering both boxes as one body, it would have a total mass of 4.0 kg. By Newton's second law, the 32 N force applies an acceleration a such that
∑ F = 32 N = (4.0 kg) a → a = 8.0 m/s²
and both boxes share this acceleration. (There is no friction, so the given force is the only one involved in the direction of the boxes' motion.)
Now consider just the smaller box. It is feeling the effect of the 32 N push in one direction and, as it comes into contact with the larger box, a normal force that points in the opposite direction. Let n be the magnitude of this normal force; this is what you want to find. By Newton's second law,
∑ F = 32 N - n = (1.0 kg) (8.0 m/s²)
n = 32 N - 8.0 N
n = 24 N
Just to make sure that this is consistent: by Newton's third law, the larger box feels the same force but pointing in the opposite direction. On the smaller box, n opposes the pushing force, so points backward. So from the larger box's perspective, n acts on it in the forward direction. This is the only force acting on the larger box, so Newton's second law gives
∑ F = 24 N = (3.0 kg) (8.0 m/s²)
Using this formula a = F/m What acceleration results from exerting a 125N force on a 0.65kg
ball?
A. 182.3 m/s^2
B. 192.3 m/s^2
C. 192.7 m/s^2
D. 162.3 m/s^2
Answer:
Acceleration = 192.3 m/s² (Approx.)
Explanation:
Given:
Force = 125 N
Mass of ball = 0.65 kg
Find:
Acceleration
Computation:
We know that;
Acceleration = Force / Mas
So,
Acceleration = 125 / 0.65
Acceleration = 192.3 m/s² (Approx.)
an ice skater is moving across a flat and level skating rink and is speeding up. which one of the following statement is true of the ice skater
Answer:
where are the statements
Explanation:
Baggage on the floor of the baggage car of a high-speed train is not prevented from moving other than by friction. The train is travelling down a 5 percent grade when it decreases its speed at a constant rate from 144 mi/h to 66 mi/h in a time interval of 12 s. Determine the smallest allowable value of the coefficient of static friction between a trunk and the floor of the baggage car if the trunk is not to slide.
Answer:
μ = 0.36
Explanation:
This exercise must be solved in parts
Let's start by finding the acceleration of the train, using the kinematics relations
v = v₀ - a t
a = [tex]\frac{v - v_o}{t}[/tex]
let's reduce the magnitudes to the SI system
v = 66 mi / h (5280 ft / 1mile) (1h / 3600s) = 96.8 ft / s
v₀ = 144 mi / h = 211.2 ft / s
let's calculate
a = [tex]\frac{96.8 - 211.2}{12}[/tex]
a = - 9.53 ft / s²
Now we can use Newton's second law, for this let's set a reference system with the x axis parallel to the slope of the hill
let's break down the weight
sin 5 = Wₓ / W
cos 5 = W_y / W
Wₓ = W sin 5
W_y = W cos 5
Y axis
N- W_y = 0
N = W cos 5
X axis
Wₓ -fr = m a
mg sin 5 - fr = ma
the friction force has the expression
fr = μ N
fr = μ W cos 5
we substitute
mg sin 5 - μ mg cos 5 = ma
g sin 5 - μ g cos 5 = a
μ = [tex]\frac{g \ sin 5 -a }{g \ cos 5}[/tex]
μ = [tex]tan 5 - \frac{a}{ g \ cos 5}[/tex]
let's calculate
μ = tan 5 - (-9.53) / 32 cos 5
μ = 0.08749 + 0.2733
μ = 0.36
A plano concave lens is one that has a surface that curves inward on one side and flat on the other, making the lens thinner at its center than at its edges. Its effect on light is :________
a. to diverge in incident eam of light
b. to make it appear as if incident parallel light is coming from a point close to the lens on the opposite side from the light source
c. to make it appear as if incident parallel light is coming from a point close to the lens on the same side as the light source
d. to converge light to a focus
Answer:
true statements are: A and C
Explanation:
In geometric optics, lenses are one of the most used elements, in general the curved surface, if they are convex, form real images, that is, the light rays have to converge at a point.
Concave lenses tend to create virtual images or I know that the extensions of the rays are what form the image.
The flat surface does not create changes in the image.
With these characteristics, let's examine the different true statements are: A and C
A) the rays diverge,
c) the rays parallel to the diverges their extensions are at a point on the same side of the lens this point is called focal length.
What component of fitness should you work on every time you exercise?
Answer:
1.body composition, (2) flexibility, (3) muscular strength, (4) muscular endurance, and (5) cardio respiratory endurance.
Explanation:
Answer:
The component of fitness you should work on every time you exercise are your muscular strength, muscular endurance, physique (body composition), your flexibility, and endurance.
Explanation:
it is important to focus on these types of exercise in order to have a well balanced routine/fitness and to stay in fit.
hope this helps !:)
if stretching a spring constant of
Answer:
5.71 N/m
Explanation:
From the question given above, the following data were obtained:
Extention (e) = 3.5 m
Force (F) = 20 N
Spring constant (K) =?
From Hooke's law,
F = Ke
Where :
F => is the force applied
e => is the extention caused by the force
K => is the spring constant
With the above formula, we can obtain the spring constant of the spring as follow:
Extention (e) = 3.5 m
Force (F) = 20 N
Spring constant (K) =?
F = Ke
20 = K × 3.5
Divide both side by 3.5
K = 20 / 3.5
K = 5.71 N/m
Thus, the spring constant of the spring is 5.71 N/m
Explain how a transistor behaves as a switch
Answer:
With a zero signal applied to the Base of the transistor it turns “OFF” acting like an open switch and zero collector current flows. With a positive signal applied to the Base of the transistor it turns “ON” acting like a closed switch and maximum circuit current flows through the device.
Explanation:
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A transistor is a semiconductor device that can function as an electronic switch, controlling the flow of current between its two main terminals.
It has three terminals: the emitter, the base, and the collector. In the context of a common bipolar junction transistor (BJT), here's how it behaves as a switch:
BJT Basics:
A BJT comes in two types: NPN (Negative-Positive-Negative) and PNP (Positive-Negative-Positive). For simplicity, let's consider the NPN type. In an NPN transistor, the emitter is made up of an N-type semiconductor, the base is a P-type semiconductor, and the collector is an N-type semiconductor.
Operating Regions:
A transistor has three operating regions: cutoff, active, and saturation.
Cutoff Region: When no current flows from the collector to the emitter. The transistor is effectively "off" in this state.
Active Region: When the transistor is operating as an amplifier, allowing a controlled current flow between the collector and emitter based on the current flowing into the base terminal.
Saturation Region: When the transistor is fully turned on, and maximum current flows from the collector to the emitter. The transistor is effectively "on" in this state.
Switching Operation:
To use a transistor as a switch, we configure it to work in either the cutoff or saturation region. The active region is avoided because it allows variable current flow, which is not desired for a switch.
a. NPN Transistor as a Switch:
To turn the NPN transistor "ON" (saturation), a small current is passed from the base to the emitter (IB). This current allows a larger current to flow from the collector to the emitter (IC).
To turn the NPN transistor "OFF" (cutoff), no current is allowed to flow into the base terminal (IB = 0). Consequently, no significant current flows from the collector to the emitter, and the transistor behaves as an open switch.
b. PNP Transistor as a Switch:
The PNP transistor works similarly but in the opposite direction. To turn it "ON" (saturation), a small current flows from the emitter to the base (IB). This enables a larger current to flow from the emitter to the collector (IC).
To turn the PNP transistor "OFF" (cutoff), the current flowing into the emitter is restricted (IB = 0), causing the transistor to behave as an open switch.
Applications:
Transistors used as switches find applications in digital logic circuits, microcontrollers, and other electronic devices. They play a crucial role in controlling the flow of current through various components, enabling or disabling functionalities as needed.
It's essential to note that when using transistors as switches, care should be taken to ensure that the base current (IB) and collector current (IC) remain within safe operating limits to prevent damage to the transistor and the circuit. Proper resistors or other current-limiting mechanisms are often employed to control these currents.
To know more about transistor here
https://brainly.com/question/34231699
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Calculate the force of Earth's gravity on a spacecraft 3.00 Earth radii above the Earth's surface if its mass is 1500 kg.
Answer in Newton’s.
F= ? N
Answer:
7
Explanation:
What happens after the president gives the budget to Congress?
Answer: The president submits a budget to Congress by the first Monday in February every year. The budget contains estimates of federal government income and spending for the upcoming fiscal year and also recommends funding levels for the federal government.
Explanation:
Answer: The president submits a budget to Congress by the first Monday in February every year. The budget contains estimates of federal government income and spending for the upcoming fiscal year and also recommends funding levels for the federal government.
Your welcome!! :)
Suppose a mad scientist went back in time to the beginning of the solar system and caused the newly formed Mars and Venus to switch places. So now there is a Venus-sized planet where Mars was (let's call it Venus 2), and a Mars-sized planet where Venus was (let's call it Mars 2). How would these hypothetical new planets, Mars 2 and Venus 2, turn out in this alternate time line
Answer:
Mars2 illuminated side of the planet is very heat, dark side very cool
Venus 2 a warm planet with a constant temperature across the entire surface
Explanation:
For this hypothetical case, when changing the planets they are changed with their current characteristics.
Case of Mars2
In this case, there is a planet with a very thin atmosphere, so the solar radiation reaches the ground without damping it, causing a lot of noise, so the illuminated side of the planet is very heat and when the dark side turns due to the little atmosphere it loses everything the heat for which it is very cold.
This thermal stress between the two sides of the planet continues constantly creating possible fruit trees in its rocky systems.
Case of Venus 2
The planet has a high atmospheric density, but it is very far from the sun, so the amount of radiation that arrives slightly warms the planet, but due to the thin atmosphere the losses for the dark period are very small, so the entire planet it is heated until it reaches an almost uniform temperature over its entire surface.
In this case we have a warm planet with a constant temperature across the entire surface, regardless of which side is lit.
Calculate the displacement Vector for a particle moved From Thepoint
(4, 3, 2) to a point (8,3,6)
Answer:
first braliest me
Explanation:
What is the kinetic energy of a 6 kg and 2 m long thin rod that rotates with angular velocity of 10 rad/s
about an axis that passes at its edge?
A. 2400 J
B. 1200 J
C. 200 J
D. 800J
Answer:
1200 J
Explanation:
From the question
K.E = 1/2mv²...................... Equation 1
Where K.E = Kinetic Energy, m = mass of the rod, v = velocity of the rod
But
V = ωr..................... Equation 2
Where ω = angular velocity of the rod, r = radius of the rod.
Substitute equation 2 into equation 1
K.E = 1/2m(ωr)²..................... Equation 3
Given: m = 60 kg, ω = 10 rad/s, r = 2 m
Substitute these values into equation 3
K.E = 1/2(6)(10×2)²
K.E = 3×(20)²
K.E = 3×400
K.E = 1200 J
Which of the following statements is not true of vibrations
Answer:
Forced vibrations, such as those between a tuning fork and a large cabinet surface, resulting in a much lower sound than was produced by the original vibrating body.
Explanation:
Just took the test, this is correct. :)
Chromosomes are a form of blood cells.
True
False
............................
(hi if u want brainlist's answer this question then ask another random question on your page so u can give me brainlist back, also i need to people to answer so i can chose one of you guys to give the brainlist's to, deal or no?)
Answer:
false im just trying to get it if you'd like to give it to me
The answer is false :)
Key Stage 3 Science - Physics
Question 19 of 35
Calculate the force applied in newtons) if a pressure of 150Pa is acting on an area of 25m².
Answer:
F = 3750 N
Explanation:
Given that,
Pressure, P = 150 Pa
Area, a = 25m²
We need to find the force applied. We know that, pressure is equal to the force acting per unit area. It can be given by :
[tex]P=\dfrac{F}{A}\\\\F=P\times A\\\\F=150\ Pa\times 25\ m^2\\\\F=3750\ N[/tex]
So, the required force is 3750 N.
An ice cube in a glass of water is pushed to the bottom of the glass and held there with a straw. Consequently, the buoyant force on the ice cube is now a. the same as when the cube was floating at the top. b. exactly balanced by the weight of the ice cube. c. exactly balanced by the force exerted by the straw. d. greater than when the cube was floating at the top.
Answer:d
Explanation:
Given
Initially, the ice cube is floating over the water
When the cube is pressed to touch the bottom, it is submerged fully
Therefore more buoyant force is acting on it
At first, a part of the volume is submerged in the water, so the buoyant force is less, but as the entire cube is immersed in the water, the buoyant force increases.
Which statement best compares gamma rays to the other components of the electromagnetic spectrum?
Am I correct ???
Answer:
no
Explanation:
gamma rays do have the most frequency, but they also have the highest amount of energy because they happen the most often.
A net force of –8750N is used to stop of 1250.kg car travelling 25m/s. What braking distance is needed to bring the car to a halt?
Answer:
d = 44.64 m
Explanation:
Given that,
Net force acting on the car, F = -8750 N
The mass of the car, m = 1250 kg
Initial speed of the car, u = 25 m/s
Final speed, v = 0 (it stops)
The formula for the net force is :
F = ma
a is acceleration of the car
[tex]a=\dfrac{F}{m}\\\\a=\dfrac{-8750}{1250}\\\\a=-7\ m/s^2[/tex]
Let d be the breaking distance. It can be calculated using third equation of motion as :
[tex]v^2-u^2=2ad\\\\d=\dfrac{v^2-u^2}{2a}\\\\d=\dfrac{0^2-(25)^2}{2\times (-7)}\\\\d=44.64\ m[/tex]
So, the required distance covered by the car is 44.64 m.
Joe is carrying a load of building supplies and likely injuring his back by supporting 882 in of weight. Calculate the mass of what he is carrying
Answer:
Answer is c because in exothermic reactions, energy releases.in cellular respiration,atp+h20 (water) = adp+ pi + energyso celullar respiration is exothermic and releases energy
Explanation:
Answer is c because in exothermic reactions, energy releases.in cellular respiration,atp+h20 (water) = adp+ pi + energyso celullar respiration is exothermic and releases energy
A 10 kg box initially at rest is pulled with a 50 N horizontal force for 4 m across a level surface. The force of friction acting on the box is a constant 20 N. How much work is done by the normal force pushing up on the box from the ground?
A. 10 J
B. 0 J
C. 100 J
D. 50 J
Answer: 0 j
Explanation:
It is given that,
Mass of the box, m = 10 kg
Force with which the box is pulled, F = 50 N
It is moved a distance of 4 m
Force of friction acting on the box, f = 20 N
We need to find the initial kinetic energy the box have. It is clear that the box is at rest initially. As there is no motion in the box at that time. The formula for the kinetic energy of the box is given by :
As v = 0
So, the initial kinetic energy of the box is 0. Hence, this is the required solution.