Complete question is;
Use a variation model to solve for the unknown value.
The stopping distance of a car is directly proportional to the square of the speed of the car.
a. If a car traveling 50 mph has a stopping distance of 170 ft, find the stopping distance of a car that is traveling 70 mph.
b. If it takes 244.8 ft for a car to stop, how fast was it traveling before the brakes were applied?
Answer:
A) d = 333.2 ft
B) 60 mph
Explanation:
Let the stopping distance be d
Let the speed of the car be v
We are told that the stopping distance is directly proportional to the square of the speed of the car. Thus;
d ∝ v²
Therefore, d = kv²
Where k is constant of variation.
A) Speed is 50 mph and stopping distance of 170 ft.
v = 50 mph
d = 170 ft = 0.032197 miles
Thus,from d = kv², we have;
0.032197 = k(50²)
0.032197 = 2500k
k = 0.032197/2500
k = 0.0000128788
If the car is now travelling at 70 mph, then;
d = 0.0000128788 × 70²
d = 0.06310612 miles
Converting to ft gives;
d = 333.2 ft
B) stopping distance is now 244.8 ft
Converting to miles = 0.046363636 miles
Thus from d = kv², we have;
0.046363636 = 0.0000128788(v²)
v² = 0.046363636/0.0000128788
v² = 3599.99658
v = √3599.99658
v ≈ 60 mph
How many molecules do we have for Na2Co3?
105.9888 g/mol is the mass as far as i know, Don't know the amount of molecules tho.
mark me brainliestt :))
A 500 Kg block is attached with a rope of length 5m, having area 0.4× 10-4 m2. If final length is 6m, Calculate the Stress, Strain and Young's Modulus?
Answer:
stress = 1.225 x 10^8 N/m^2
strain = 1/5
Young's modulus = 6.125 x 10^8 N/m^2
Explanation:
mass, m = 500 kg
length, L = 5 m
Area, A = 0.4 x 10^-4 m^2
Final length, L' = 6 m
extension, x = L'-L= 6 - 5 = 1 m
Stress is defined as force per unit area.
[tex]stress =\frac{Force}{Area}\\\\stress =\frac{500\times 9.8}{0.4\times 10^{-4}}\\\\stress = 1.225\times 10^8 N/m^2[/tex]
Strain is defined as the ratio of change in length to the original length.
[tex]strain =\frac{x}{L}\\\\strain = \frac{1}{5}[/tex]
Young's modulus is given by the ratio of stress to the strain.
[tex]Y = \frac{1.225 \times 10^8}{\frac{1}{5}}\\\\Y = 6.125\times 10^8 N/m^2[/tex]
Larry sees a group of people weeping, with frowns on their faces and their eyes turned down. Larry their expressions to understand that they are feeling sadness.
Select one:
a. misinterprets
b. decodes
C. encodes X
d. recodes
Answer:
c
Explanation:
no need explanation u can trust me
Choose the CORRECT statements. The superposition of two waves.
I. refers to the effects of waves at great distances.
Il. refers to how displacements of the two waves add together.
Ill. results into constructive interference and destructive interference
IV. results into minimum amplitude when crest meets trough.
V. results into destructive interference and the waves stop propagating.
A. I and II
B. II and III
C. I, II and III
D. II, III and IV
E. III, IV and V
F. II, III, IV and V
Answer:
A
Explanation:
I guess not that much confidential!
How fast much an 816kg Volkswagen travel to have the same momentum as (a) a 2650kg Cadillac going 16.0 km/h? (b) a 9080-kg truck also going 16.0 km/hr?
Explanation:
(a) The momentum of a 2650kg Cadillac going 16.0 km/h or 4.44 m/s is :
p = 2650 kg × 4.44 m/s
= 11766 kg-m/s
(b) The momentum of a 9080-kg truck also going 16.0 km/hr or 4.44 m/s is :
p =mv
= 9080-kg × 4.44 m/s
= 40315.2 kg-m/s
If p = 11766 kg-m/s, velocity is :
[tex]v=\dfrac{p}{m}\\\\v=\dfrac{11766 }{816}\\\\=14.41\ m/s[/tex]
If p = 40315.2 kg-m/s, velcocity is :
[tex]v=\dfrac{p}{m}\\\\v=\dfrac{40315.2}{816}\\\\=49.40\ m/s[/tex]
Hence, this is the required solution.
Azam had a metal pencil box and a wooden block on his table. When he touched them, the pencil box felt colder compared to the wooden block. When he measured their temperatures using a thermometer, he found that both the objects were at the same temperatures. What could be the reason for Azam to 'feel' that the pencil box was cooler? * (1 Point) Air around the pencil box was at a lower temperature which made the pencil box colder Wood produces heat and so, must have been at a higher temperature than the pencil box As metal is a better conductor of heat, it drew away heat from his hand faster than the wooden block. Metals are always at a lower temperature than other substances and so, there has been an error in measurement
The third choice is the correct explanation. Don't make me type it all out on my phone.
Why did vygotsky believe that children were more dependent learners
Answer:
Vygotsky's sociocultural theory asserts that learning is an essentially social process in which the support of parents, caregivers, peers and the wider society and culture plays a crucial role in the development of higher psychological functions.
Thus, Vygotsky believed that children were more dependent learners
A person is driving a car down a straight road. The instantaneous acceleration is constant and in the direction of the car's motion. 1) The speed of the car is increasing. decreasing. constant. increasing but will eventually decrease. decreasing but will eventually increase.
Answer:Increasing
Explanation:
Given
Car is driven on the straight road with instantaneous acceleration in the direction of car's motion.
If instanateneous acceleration is constant then speed of car is increasing at a constant pace. As there are no turns on the road, therefore speed of car is increasing.
The speed of the car is "decreasing". A further description is provided in the below paragraph.
It's because the individual would be in a straightforward fashion. This same acceleration inclination comes contrary to the movement of the automobile. It indicates that it exerts pressure against the movement of the automobile. So, when it moves forward, the speed of the automobile decreases.
Thus the above answer is correct.
Learn more about the speed here:
https://brainly.com/question/5053192
calculate the electric potential 3mm from a point charge of 16Nc
[tex]4.8 \times 10^8[/tex] volts
Explanation:
The electric potential due to a point charge is given by
[tex]V= \dfrac{1}{4 \pi \varepsilon_{0}} \dfrac{Q}{r}[/tex]
where Q = charge = [tex]16 \times 10^{-9}[/tex] C
r = distance from a point = [tex]3 \times 10^{-3}[/tex] m
[tex]\varepsilon_{0}[/tex] = permitivity of free space
= 8.85×10^-12 C^2/N-m^2
Plugging in the numbers,
[tex]V = \dfrac{1}{4 \pi (8.85 \times 10^{-12})} \dfrac{16 \times 10{-9}}{3 \times 10^{-3}}[/tex]
[tex]= 4.8 \times 10^8[/tex] volts
Which one of the following pairs of units may not be added together, even after the appropriate unit conversions have been made?
a. grams and milligrams
b. miles and kilometers
c. kilometers and kilograms
d. centimeters and yards
Answer:
c. kilometers and kilograms
Explanation:
If two units represent different things, like for example grams and joules, where the first one is a unit for mass, and the second one a unit for energy we can not add them together. (
Let's analyze each one of the given options:
a: grams and milligrams
both grams and milligrams are units of mass, so after the appropriate unit conversions, we can add them.
b: miles and kilometers
Both are units for distance, after the appropriate unit conversions, we can add them.
c: kilometers and kilograms
"Kilometer" is a unit for distance, and "kilogram" a unit for mass, we can not add distance and mass, so these two can not be added together.
d: centimeters and yards
Both are units of distance, after the appropriate unit conversions, we can add them.
Then the only one that we can not add together is option c: kilometers and kilograms
Answer: The correct option is C (kilometers and kilograms).
Explanation:
UNITS is the quantity of a constant magnitude which is used to measure the magnitudes of other quantities of the same nature. The magnitude of a physical quantity is expressed as, Physical quantity = (numerical value) × (unit). There are six basic units of measurement which includes:
--> metre (m) - unit of length.
--> kilograms (kg) - unit of mass.
--> second (s) - unit of time.
--> ampere (A) - unit of electrical current.
--> kelvin (K) - unit of temperature and
--> mole (mol) - unit of the amount of substance.
Mass is the quantity of matter present in a body which is constant and is measured in KILOGRAMMES or GRAMS. While position is the distance and direction of an object from a particular reference point which is known to vary and is measured in METERS OR KILOMETRES.
From the above definition, KILOGRAMMES is used to measure the magnitude of a different quantity from KILOMETERS and therefore should not be added up after conversation.
The basal metabolic rate is the rate at which energy is produced in the body when a person is at rest. A 157 lb (71.0 kg ) person of height 5.91 ft(1.80 m ) would have a body surface area of approximately 1.90 m2 .
Reqiuired:
a. What is the net amount of heat this person could radiate per second into a room at 19.0 ∘C (about 66.2∘F) if his skin's surface temperature is 31.0 ∘C? (At such temperatures, nearly all the heat is infrared radiation, for which the body's emissivity is 1.00, regardless of the amount of pigment.)
b. Normally, 80.0 % of the energy produced by metabolism goes into heat, while the rest goes into things like pumping blood and repairing cells. Also normally, a person at rest can get rid of this excess heat just through radiation. Use your answer to part A to find this person's basal metabolic rate(BMR).
Answer:
A. Net amount of heat radiated = 109.2W
B. Person's basal energy = 136.5
Explanation:
Part A:
Area of person, A = 1.90 m^2
Temperature of person , T = 31 C
T = 304 K
Temperature of surroundings , To = 19 C
To = 282 K
Now, net amount of heat radiated = e*A*sigma *(T^4 - To^4)
Net amount of heat radiated = 1 * 1.8 * 5.6703 *10^-8 *(304^4 - 294^4)
Net amount of heat radiated = 109.2 W
The net amount of heat radiated is 109.2 W
Part B:
Person's basal energy = net amount of heat radiated /(0.80)
Person's basal energy = 109.2/0.80
Person's basal energy = 136.5 W
Person's basal energy is 136.5 W
Lực tương tác giữa hai điện tích điểm khi đặt trong không khí là 1,5 N. Nhúng hai điện tích đó vào môi trường điện môi có hằng số điện môi là 3 thì lực tương tác giữa chúng là bao nhiêu?
Answer:
The force is now 0.5 N.
Explanation:
Force = 1.5 N
dielectric constant , k = 3
Let the two charges are q and q' and the distance between them is r.
The electrostatic force between the two charges is given by
[tex]F \alpha \frac{ q q'}{r^2}..... (1)[/tex]
When a dielectric material is inserted between the two charges, the new force is
[tex]F' \alpha \frac{ q q'}{kr^2}..... (2)[/tex]
From (1) and (2)
F' = F/K = 1.5/3 = 0.5 N
At a playground, Maryam a 3-year old girl and Zahirah a 6-year old girl are playing with the swings. Maryam is sitting while Zahirah is standing on the swing. Both of them were given the same push by their mother. Choose the CORRECT statements:
A. Maryam is swinging faster than Zahirah.
B. Zahirah is swinging faster than Maryam.
C. Both swings at the same pace.
D. Maryam is swinging faster since she is younger.
E. Zahirah is swing faster since she is older.
Answer:
both swings at the same place
Explanation:
because there mother is giving same amount of force to both.
Topic: Physical and Chemical Changes
Subject: Science
Grade: 5th
Question: Why am I growing?
(Please give this answer related to Physical and Chemical Changes.
Answer: Why am I growing is a chemical change.
Explanation:
Changes that can be reversed and does not affect the composition of a substance are called physical changes.
For example, change in state of a substance like ice converting into water is a physical change.
Changes that cannot be reversed and affect the chemical composition of a substance are called chemical changes.
For example, a child growing is an irreversible change and hence, it is a chemical change.
Thus, we can conclude that why am I growing is a chemical change.
The magnification produced by spherical mirror is + 1/4. State the type of spherical mirror. State 3 characteristics of the image formed by the mirror: -
Answer:
Convex mirror.
Explanation:
Image is real.
Image is inverted.
Image is magnified.
A light hollow tube of 2.00 cm diameter and 1.0 m length is filled with tiny beads of different density. The resulting density distribution is linear, with the left end having a density of 1.6 g/cm^3, and the right end having a density of 6.3 g/cm^3. How far from the left end will be the center of mass? (give answer in cm).
Answer:
i think c
Explanation:
cause
What must a plant need to produce 4 molecules of sugar?
What must a plant need to produce 4 molecules of sugar?
Answer:
To produce a single sugar molecule a plant must use a molecule of water (H2O) and carbon dioxide (CO2) and sunlight. To get 4 molecules, you simple use 4 molecules of water and 4 molecules of carbon dioxide
The average speed of molecules of a 0.1 mole nitrogen gas in a container is 5103
m/s.
a/ Determine the total translational kinetic energy of the gas.
b/ Compute the energy as heat providing to the gas so that the average speed of its molecules increases to
double.
Answer: (a) The total translational kinetic energy of the gas is [tex]35 \times 10^{7} J[/tex].
(b) The energy as heat providing to the gas so that the average speed of its molecules increases to double is [tex]8.7 \times 10^{7} J[/tex].
Explanation:
Given: Average speed of molecules = [tex]5 \times 10^{3}[/tex] m/s
Moles = 0.1 mol
(a) As the give gas is nitrogen so its mass is 28 g/mol.
Formula to calculate translational kinetic energy is as follows.
Total translational K.E = [tex]\frac{1}{2}mv^{2}[/tex]
where,
m = mass
v = velocity
Substitute the values into above formula as follows.
[tex]Translational K.E = \frac{1}{2}mv^{2}\\= \frac{1}{2} \times 28 \times (5 \times 10^{3})^{2}\\= 35 \times 10^{7} J[/tex]
(b) As the energy is directly proportional to the square of velocity. So, when average speed of molecules increases to double then relation between energy and velocity will be as follows.
[tex]E \propto (2v)^{2}\\or, E \propto 4v^{2}\\v^{2} \propto \frac{E}{4}[/tex]
This means that velocity gets one-fourth times the energy of its molecules.
Therefore, energy will be calculated as follows.
[tex]Energy = \frac{35 \times 10^{7}}{4}\\= 8.7 \times 10^{7} J[/tex]
Therefore, we can conclude that
(a) The total translational kinetic energy of the gas is [tex]35 \times 10^{7} J[/tex].
(b) The energy as heat providing to the gas so that the average speed of its molecules increases to double is [tex]8.7 \times 10^{7} J[/tex].
Assuming the earth is a uniform sphere of mass M and radius R, show that the acceleration of fall at the earth's surface is given by g = Gm/R2 . What is the acceleration of a satellite moving in a circular orbit round the earth of radius 2R
Explanation:
The weight of an object on the surface of the earth is equal to the gravitational force exerted by the earth on the object.
[tex]W=F_G[/tex]
[tex]mg = G \dfrac{mM}{R^2}[/tex]
which gives us an expression for the acceleration due to gravity g as
[tex]g = G\dfrac{M}{R^2}[/tex]
At a height h = R, the radius of a satellite's orbit is 2R. Then the acceleration due to gravity [tex]g_h[/tex] at this height is
[tex]mg_h = G \dfrac{mM}{(2R)^2}= G \dfrac{mM}{4R^2}[/tex]
Simplifying this, we get
[tex]g_h= G \dfrac{M}{4R^2} = \dfrac{1}{4} \left(G \dfrac{M}{R^2} \right) = \dfrac{1}{4}g[/tex]
When you are standing without moving, you exert a force on the ground. Why doesn't Earth slowly start accelerating downwards?
Explanation:
You would think it should. But remember the Force is also determined by mass. The mass of the earth markes our mass like the smallest part of a mosquito leg. The earth will go on it its merry way without cosidering us at all.
Which characteristics describe a point charge
Answer:
Explanation:
It takes up no space and acts uniformly on its surroundings.
Given a point charge, or a particle of infinitesimal size, that contains a certain charge, electric field lines emanate from equally in all radial directions. If the point charge is positive, field lines point away from it; if the charge is negative, field lines point toward it.
When a Frisbee is flying horizontally through the air, the speed of the air flowing over the Frisbee's top is
Group of answer choices.
A. higher than the speed of the air beneath it and the pressure on top of the Frisbee is greater than the pressure beneath it.
B. lower than the speed of the air beneath it and the pressure on top of the Frisbee is less than the pressure beneath it.
C. lower than the speed of the air beneath it and the pressure on top of the Frisbee is greater than the pressure beneath it.
D. higher than the speed of the air beneath it and the pressure on top of the Frisbee is less than the pressure beneath it.
Answer:
D. higher than the speed of the air beneath it and the pressure on top of the Frisbee is less than the pressure beneath it.
Explanation:
Newton's Second Law of Motion states that the acceleration of a physical object is directly proportional to the net force acting on the physical object and inversely proportional to its mass.
Mathematically, it is given by the formula;
[tex] Acceleration = \frac {Net \; force}{mass} [/tex]
When a frisbee flies horizontally through the air, it experiences air above and beneath it. Also, there is a pressure acting on both on top and below the frisbee.
Typically, the air flowing over the top of the frisbee has a speed that is higher than the speed of the air beneath it.
Furthermore, the frisbee is able to remain in flight because the pressure on top of the frisbee is less than the pressure beneath it.
difference between resistor or resistance
Answer:
Resistance is the property of a conductor, which determines the quantity of current that passes through it when a potential difference is applied across it. A resistor is a electrical componet with a predetermined electrical resistance, like 1 ohm, 10 ohms 100 ohms 10000 ohms etc.
I hoped I helped you. Please mark my answer as brainliest answer.
A 10,000J battery is depleted in 2h. What power consumption is this? *
A) 5000W
B) 3W
C) 1.4W
D) 20000W
show your work please
Answer:
P = 1.4 W
Explanation:
Given that,
The work done or the energy of the battery, E = 10,000 J
Time, t = 2 h
We need to find the power consumption. Let it is P. Power is the rate of doing work. So,
[tex]P=\dfrac{W}{t}\\\\P=\dfrac{10,000}{2\times 3600}\\\\P=1.38\ W[/tex]
or
P = 1.4 W
So, the power of the battery is 1.4 W.
I provided the question above.
Answer:
Explanation:
since it is connected in parallel combination
use this formula
[tex]\frac{1}{R} = \frac{1}{R1} + \frac{1}{R2}[/tex]
[tex]\frac{1}{R} = \frac{1}{2} + \frac{1}{4}[/tex]
[tex]\frac{1}{R} = \frac{4+2}{2}[/tex]
[tex]\frac{1}{R} = \frac{6}{2}[/tex]
[tex]\frac{1}{R} = 3[/tex] ohm
therefore resistence = 3 ohm
then we should find power
P = VI
P = 12*3
P = 24 watt
now to find current use formula power = current * voltage
24 = current * 12
24/12 = current
2 = current
therefore current is 2 ampere (A).
to find potential difference (emf) use formula
V = IR
V = current * resistence
V = 2 * 3
V = 6 volt .
therefore potential difference is 6 volt.
What is the magnitude of your total displacement if you have traveled due west with a speed of 23 m/s for 135 s , then due south at 12 m/s for 295 s ?
Answer:
4708.78 m
Explanation:
Applying,
d = vt................ Equation 1
Where d = displacement, v = velocity, t = time
dispalcement due west
Given: v = 23 m/s, t = 135 s
Therefore,
d = 23(135)
d = 3105 m due west.
For south
Given: v = 12 m/s, t = 295 s
Therefore,
d = 12(295)
d = 3540 m
Note: The entire journey forms a right angle triangle
Total displacement = √(3105²+3540²)
Total displacement = √(9641025+12531600)
Total displacement = √(22172625)
Total displacement = 4708.78 m
what do you understand by Force,acceleration and mass??
Answer:
Force is a push or pull that an object can exert on other objects. Acceleration is the rate of change of an object's speed and Mass is the amount of matter in an object and is expressed in kilograms.Explanation:
It is summarized by the equation: Force (N) = mass (kg) × acceleration (m/s2).It takes a minimum distance of 98.26 m to stop a car moving at 17.0 m/s by applying the brakes (without locking the wheels). Assume that the same frictional forces apply and find the minimum stopping distance when the car is moving at 25.0 m/s.
Answer:
x_f = 212.5m
Explanation:
t = (x_f-x_0)/(.5*(v_f-v_0))
t = (98.26m-0m)/(.5(0m/s-17m/s))
t = 11.56s
a = (v_f-v_0)/t
a = (0m/s-17m/s)/11.56s
a = -1.47m/s²
t = (v_f-v_0)/a
t = (0m/s-25m/s)/-1.47m/s²
t = 17s
x_f = x_0+(.5*(v_f-v_0))*t
x_f = 0m+(.5*(0m/s-25m/s))*17s
x_f = 212.5m
A continuous succession of sinusoidal wave pulses are produced at one end of a very long string and travel along the length of the string. The wave has frequency 70.0 Hz, amplitude 5.00 mm, and wavelength 0.600 m. (a) How long does it take the wave to travel a distance of 8.00 m along the length of the string
Answer:
The time taken by the wave to travel 8 m is 0.19 s .
Explanation:
frequency, f = 70 Hz
Amplitude, A = 5 mm
Wavelength = 0.6 m
The wave speed is given by
wave speed, v = frequency x wavelength
v = 70 x 0.6
v = 42 m/s
Distance, d = 8 m
Let the time taken is t.
So, [tex]t =\frac{d}{v}\\\\t =\frac{8}{42}\\\\t = 0.19 s[/tex]
The equation of damped oscillations is given in the form x=0.05e^-0.25sin½πt (m). Find the velocity of an oscillating point at the moments of time: 0, T, 2T, 3T and 4T.
Explanation:
Finding the (maximum) respective prime powers would yield the answer. Also we need not ... Is perfectly divisible by 720^n? ... So we can say that for any positive value of n it not divisible.