Answer:
Using, s=ut+
2
1
at
2
s
1
=u+
2
1
a
or, 3=u+
2
a
∴a=6−2u
s
2
=2u+
2
1
a×4
8=2u+2a
Solving the equations
8=2u+2(6−2u)
8=2u+12−4u
2u=4
u=2m/s
∴a=6−2u=6−4=2m/s
2
The sound level at 1.0 m from a certain bullfrog is 60 dB. You are surrounded by 18 such bullfrogs, all 1.0 m from you and all croaking equally loudly at the same time. What sound level are you being exposed to
Answer:
The value is [tex]S_a = 72.56 \ dB[/tex]
Explanation:
From the question we are told that
The sound level is [tex]S = 60 dB[/tex]
The distance from the source is d = 1 m
The number of sources is n = 18
Generally the sound which the person is been exposed to is mathematically represented as
[tex]S_a = S + 10log(18)[/tex]
=> [tex]S_a = 60 + 10log(18)[/tex]
=> [tex]S_a = 72.56 \ dB[/tex]
The scientific method can easily be misinterpreted as ___________. Question 1 options: a great magical trick, or slide of hands, rather than factual an "auto mechanics" guide to Science Investigation a "cookbook" recipe for performing scientific investigations the perfect method for finding the answers to all questions
Answer:
I think the answer is
a "cookbook" recipe for performing scientific investigations
Explanation:
Select the best answer for the question.
7. What is the amount of MMF generated by a 50-turn electromagnetic coil supplied by 12 VDC at a current of 1 ampere?
O A. 50 ampere-turns
B. 38 ampere-turns
C. 12 ampere-turns
D. 600 ampere-turns
The correct answer is 600 ampere-turns
We shall first get the expression that provides the magnetomotive force. It is calculated by multiplying the number of spins on the wire by the current flowing through it. To get the solution, we shall alter and substitute the necessary values.
It is crucial to keep in mind that magnetomotive force (mmf), which is similar to electromotive force (emf), drives a current of electrical charge through magnetic circuits. The phrase "magnetomotive force" is deceptive, though, as it neither denotes a force nor something that moves.
M.M.F = NI
N= 50
I = 12 at a current of 1 ampere
M.M.F = NI
= 50 × 12
=600 ampere-turns
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A bus leaves an intersection accelerating at +2.0 m/s2. Part A Where is the bus after 7.5 s?
Express your answer to two significant figures and include the appropriate units.
The distance covered is 56 m.
What is acceleration?We define acceleration as the rate at which the velocity changes with time. We can find the position of the bus by the use of the equations of kinematics.
Using the equation;
s = ut + 1/2at^2
u = initial velocity
a = acceleration
t = time taken
Since the bus started from rest u = 0 m/s
s = 1/2at^2
s = 0.5 * 2 * (7.5)^2
s = 56 m
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A bowling ball with a mass of 5 kg is rolled at an acceleration of 2 m/s2. What is the force of the bowling ball when it hits the pins? (Hint: Force = ?)
Answer:
[tex]F=10\ N[/tex]
Explanation:
[tex]We\ are\ given\ that,\\Mass\ of\ the\ bowling\ bowl=5\ kg\\Acceleration\ of\ the\ ball=2\ m/s^2\\Hence,\\As\ we\ know\ that\ F=ma\\Here,\\Force\ of\ the\ bowling\ ball\ when\ it\ hits\ the\ pins=Mass\ of\ the\ bowling\ bowl* its\ Acceleration.\\Hence,\\F=5*2\\F=10\ Newtons\\[/tex]
A cyclist travels from point A to point B for 10 minutes. During the first 2.0 minutes of her trip, she maintains a uniform acceleration of 0.076 m/s2. She then travels at constant velocity for the next 5.0 minutes. Next, she decelerates at a constant rate so that she comes to a rest at point B 3.0 minutes later
What is the acceleration during the last 3.0 minutes
Answer:
im not really good at explaining, but i found this website url:
https://www.numerade.com/questions/a-cyclist-travels-from-point-a-to-point-b-in-10-min-during-the-first-20-min-of-her-trip-she-maintain/
same question just with the explanation
QUESTION 1
energy is the work done by a force acting through a distance.
[tex]acslerishne[/tex]
pressure problem solving..
We know that Formula to calculate Pressure is Pressure = Force/Area.
It is given that the Water jet exerts a pressure of 20 Mega Pascal on an area of 5m². We convert 20 Mega pascal to Pascal => 20 * 1000000 So, we get Pressure P = 20000000 Pascals, Area = 5 m² Putting values we get Force = P * A => Force = 20000000 * 5
=> Force = 100000000 N
Status weighs 2400 N and base area is 500 cm². Converting the base area from cm² to m², we get Area a = 0.05 m², Force F = 2400 N. Putting values we get Pressure = 2400 * 0.05=> Pressure = 48000 Pascal
It is given that the base area of an object = 3 cm² and the pressure exerted will be 21 Pa. Firstly, We will convert the area from cm² to m² and we get Area a = 0.0003 m², and P = 21 Pa. Putting values in equation we get Force/ Weight of object => F = P*A => F = 21 * 0.0003=> F = 0.0063 N
It is given that the lady weighs 50 kN so, Force F = 50 kN. We will convert force from kN to N => F = 50 * 1000 => F = 50000 N. And, the surface area of heels is 0.0001 m². Putting values in equation, We get : Pressure = F/A => P = 50000/0.0001=> P = 500000000 Pa
It is given that the pressure box exerts on the ground is 20 kPa. The weight of the box is 400 N. First, we will convert pressure from kPa to Pa. Pressure = 20 * 1000 => P = 20000 Pa and Force F = 400 N. Putting these values in equation we get Area = F/P =>Area = 400/20000 => Area = 0.02 m²
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The wheel attached to a bicycle has a diameter of .59 m. If the wheel makes 7 rotations in a second, how fast is the cyclist traveling
Answer: the cyclist traveling at 12.96 m/s
Explanation:
Given that;
diameter = 0.59 m
radius = 0.295 m
the wheel makes 7 rotations in a second,
in every rotation, it travels a distance of 2πr
so
total distance
= 7 × 2πr
= 7 × 2 × 3.14 × 0.295
= 12.96 m
Therefore velocity = 12.96 m/s
so the cyclist traveling at 12.96 m/s
8th grade science, Two questions.
Please help me
Answer:
for 10 some advantages are that it has a much better bandwidth,low power loss, and it allows for longer transmission distance.
You are pushing a large box across a frictionless floor by applying a constant horizontal force. If the box starts at rest, you have to do work W 1 in order for the box to travel a distance d in time T . How much work would you have to do, in terms of W 1 , to make the box go the same distance in half the time
Answer:
You would have to do four times the work W₁ to make the box go the same distance in half the time.
Explanation:
By definition work is:
[tex] W = F*d [/tex] (1)
Where:
F: is the force and d: is the distance
On the other hand, the force is given by:
[tex] F = ma [/tex] (2)
By entering equation (2) into (1):
[tex] W = F*d = m*a*d [/tex] (3)
Also, we can express the acceleration in terms of distance and time by using the following kinematic equation:
[tex] d_{f} = d_{0} + v_{0}t + \frac{1}{2}at^{2} [/tex] (4)
Where:
[tex]d_{f}[/tex]: is the final distance
[tex]d_{0}[/tex]: is the initial distance = 0
[tex]v_{0}[/tex]: is the initial speed = 0 (the box starts at rest)
t: is the time
[tex] d_{f} = \frac{1}{2}at^{2} [/tex]
Solving for a:
[tex] a = \frac{2d_{f}}{t^{2}} [/tex] (5)
Initially we have:
t = T₁, W = W₁, [tex]d_{f}[/tex] = d
[tex] a_{1} = \frac{2d}{T_{1}^{2}} [/tex]
[tex] W_{1} = m*a_{1}*d = m*d*\frac{2d}{T_{1}^{2}} = 2m(\frac{d}{T_{1}})^{2} [/tex]
And when the box goes the same distance in half the time:
[tex] t = \frac{T_{1}}{2} [/tex]
The acceleration is (from equation 5):
[tex]a_{2} = \frac{2d_{f}}{t^{2}} = \frac{2d}{(\frac{T_{1}}{2})^{2}} = \frac{8d}{T_{1}^{2}}[/tex] (6)
Finally, the work W₂ in terms of W₁ is:
[tex]W_{2} = m*a_{2}*d = m*d*\frac{8d}{T_{1}^{2}} = 8m(\frac{d}{T_{1}})^{2} = 4*[2m(\frac{d}{T_{1}})^{2}] = 4W_{1}[/tex]
Therefore, you would have to do four times the work W₁ to make the box go the same distance in half the time.
I hope it helps you!
what is the main cause of seafloor spreading?
Answer:
As tectonic plates slowly move away from each other, heat from the mantle's convection currents makes the crust more plastic and less dense.
Explanation:
Answer: The main cause of sea floor spreading are the directions and force of the moving tectonic plates.
Explanation:
What is the velocity of a group of explorers traveling from Antarctica to Australia, traveling 1500 miles in 48 hours?31.25 mph south
72,000 mph
48 mph
31.3 mph north
Answer:
31.3mph North
Explanation:
Given parameters:
Distance traveled = 1500miles
Time taken = 48hrs
Unknown:
Velocity of the group of explorers = ?
Solution:
Velocity is the displacement divided by the time taken. It is a vector quantity with both magnitude and direction.
So;
Velocity = [tex]\frac{displacement}{time}[/tex]
Displacement is the distance moved in a specific direction = 1500miles North
Insert the parameters and solve;
Velocity = [tex]\frac{1500}{48}[/tex] = 31.3mph North
Which term is described as a seamount with a flattened top?
deep-sea trenches
guyots
continental shelf
abyssal plains
The term which is described as a seamount with a flattened top is called as guyots.
Guyot, commonly known as Tablemount, is an uninhabited submarine volcano with a flat peak that is more than 200 meters (660 feet) above sea level. These flat summits could be more than 10 kilometres in circumference (6 miles).
Seamounts called guyots have grown above sea level. The seamount's top was eroded by erosion by waves, leaving it with a flattened shape. The sea bottom gradually falls as a result of the ocean floor moving away from oceanic ridges, submerging the flattened guyots to form undersea flat-topped peaks. Once the guyot is formed, on it's top a coral colony will start developing and little by little make a circle shaped island, which represents the formation of the atoll.
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why the efficiency of heat engine is always less than 100%
Answer:
because some waste heat is always produced produced in a heat engine.
Explanation:
the fraction of heat input that is converted to a net work output is a measure of the performance of the heat engine and is called the thermal efficiency.Since the machine does not contain a source of energy ,nor can it store energy ,from this conversation of energy the power output of machine can never be greater than its input,so efficiency can be less than 100%.
Explanation:
The efficiency of heat engine is always less than 100% most of the times because of waste energy in form of heat.
Different forms of heating occurs during the working of an engine As the mechanical workings of the engine sets in motion, heat is generated. One of the most common type of the heat is the frictional heating. Therefore, as energy is transformed from one form to another, some are lost as heat. In this regard, the efficiency of the engine suffers.
Elements known as noble gases do not have the ability or the room in their valence
electron shell to form bonds with other elements.
O True
O False
Answer:
true
Explanation:
noble gases are octet meaning they they have eight electrons in their outer shell so the are stable
A person travels by car from one city to another. She drives for 30.1 min at 82.1 km/h, 9.11 min at 83.1 km/h, 49.6 min at 41.3 km/h, and spends 18.7 min along the way eating lunch and buying gas. Determine the distance between the cities along this route. Answer in units of km.
The distance between the cities along the route is 87.95 Km
What is speed?Speed is the distance travelled per unit. Mathematically, it can be expressed as:
Speed = distance / time
How to determine the distance travelled in 30.1 minsTime = 30.1 mins = 30.1 / 60 hourSpeed = 82.1 Km/hDistance =?Speed = distance / time
Cross multiply
Distance = speed × time
Distance = 82.1 × (30.1 / 60)
Distance = 41.19 Km
How to determine the distance travelled in 9.11 minsTime = 9.11 mins = 9.11 / 60 hourSpeed = 83.1 Km/hDistance =?Speed = distance / time
Cross multiply
Distance = speed × time
Distance = 83.1 × (9.11 / 60)
Distance = 12.62 Km
How to determine the distance travelled in 30.1 minsTime = 49.6 mins = 49.6 / 60 hourSpeed = 41.3 Km/hDistance =?Speed = distance / time
Cross multiply
Distance = speed × time
Distance = 41.3 × (49.6 / 60)
Distance = 34.14 Km
How to determine the distance between the citiesDistance travelled in 30.1 mins = 41.19 KmDistance travelled in 9.11 mins = 12.62 KmDistance travelled in 49.6 mins = 34.14 KmTotal distance =?Total distance = 41.19 + 12.62 + 34.14
Total distance = 87.95 Km
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A copper rod has a length of 1.7 m and a cross-sectional area of 3.2 × 10-4 m2. One end of the rod is in contact with boiling water and the other with a mixture of ice and water. What is the mass of ice per second that melts? Assume that no heat is lost through the side surface of the rod.
Given :
A copper rod has a length of 1.7 m and a cross-sectional area of [tex]3.2 \times 10^{-4} \ m^2[/tex].
One end of the rod is in contact with boiling water and the other with a mixture of ice and water.
To Find :
The mass of ice per second that melts.
Solution :
Amount of heat transfer from boiling water to ice through the copper bar is :
[tex]Q = \dfrac{kA\Delta T }{L}\\\\Q = \dfrac{390\times 3.2 \times 10^{-4} \times 100}{1.7}\\\\Q = 7.34 \ J/s[/tex]
Let, amount of ice melts per second is :
[tex]m=\dfrac{Q}{L_f}[/tex]
Here, [tex]L_f[/tex] is the latent of fusion of water and is equal to [tex]L_f = 3.34\times 10^5 \ J/s[/tex].
Putting all values in above equation, we get :
[tex]m=\dfrac{7.34}{3.34\times 10^5}\\\\m = 2.19 \times 10^{-5} \ kg/s[/tex]
Hence, this is the required solution.
On a chilly 12∘C day, you quickly take a deep breath--all your lungs can hold, 4.0 L. The air warms to your body temperature of 37∘C.
If the air starts at a pressure of 1.0 atm, and you hold the volume of your lungs constant (a good approximation) and the number of molecules in your lungs stays constant as well (also a good approximation), what is the increase in pressure inside your lungs?
Answer:
The increase in pressure inside the lungs is 0.09 atm
Explanation:
From the Pressure law
Pressure law states that the volume of a fixed mass of gas is directly proportional to the absolute temperature provided that the volume remains constant.
That is,
P ∝ T
Where P is the Pressure and T is the temperature.
Then, we can write that
P = kT
Where k is the proportionality constant
∴ [tex]\frac{P}{T} = k[/tex]
Then,
[tex]\frac{P_{1} }{T_{1} } = \frac{P_{2} }{T_{2} }[/tex]
From the question, [tex]P_{1}[/tex] = 1.0 atm
[tex]{T_{1}[/tex] = 12 °C = (12 + 273.15) K = 285.15K
[tex]{T_{2}[/tex] = 37 °C = (37 + 273.15) K = 310.15K
Therefore,
[tex]\frac{1.0}{285.15} = \frac{P_{2} }{310.15}[/tex]
[tex]P_{2} = \frac{1.0 \times 310.15}{285.15}[/tex]
[tex]P_{2} = 1.09[/tex] atm
Increase in pressure = [tex]P_{2} - P_{1}[/tex] = 1.09 atm - 1.0 atm
Increase in pressure = 0.09 atm
Hence, the increase in pressure inside the lungs is 0.09 atm
At constant volume, pressure of the gas is directly proportional to the temperature of the gas. The increased pressure inside the lungs is 0.9 atm.
From Gas law,
[tex]\bold {\dfrac {P_1} {T_1 } = \dfrac {P_2} {T_2 } }[/tex]
Where,
P1 - initial pressure = 0.1 atm
P2 - final pressure = ?
T1 - initial temperature = 12 °C = (12 + 273.15) K = 285.15 K
T2 - final temperature = 37 °C = (37 + 273.15) K = 310.15 K
Put the values in the formula,
[tex]\bold {\dfrac {1.0} {285.15 } = \dfrac {P_2} {310.15 } }[/tex]
[tex]\bold {P_2 = 1.09\ atm}[/tex]
Thus, increased pressure in the lungs
= 1.9 - 1.0
= 0.9 atm
Therefore, the increased pressure inside the lungs is 0.9 atm.
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A ball is thrown horizontally at a height of 1.5 meters at a velocity of 70 m/s. Assume no air resistance. How far did the ball travel horizontally when it hit the ground?
15.4 m
38.5 m
67 m
45.5 m
Answer:
38.5
Explanation:
Greta 30 m away her truck she noticed she forgot her tea and returns back to his house. Her total travel time is 240 seconds what is greta average velocity ?
Finding average speed distance
avg = distance/time
time1 – 30 ml + 30 ml
240 s60 m240 s= 0.25m/s
The correct answer is:
• average velocity = 0 m/s
• average speed = 0.25 m/s
What is average speed?The pace at which an object's direction changes as it is traveling is referred to as its velocity and is measured by a particular unit of time and from a particular point of view.
Greta returns to his house after realizing she forgot her tea 30 meters from her pickup. Her journey takes 240 seconds in all.
What is Greta average velocity ?Avg = distance/time time for calculating average speed distance
1 - 30 ml + 30 ml
240 s60 m
240 s= 0.25m/s
The right response is:
• Average speed: 0 m/s
• The typical speed is 0.25 m/s
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A roller coaster at an amusement park has a dip that bottoms out in a vertical circle of radius 11.0 m. A passenger feels the seat of the car pushing upward on her with a force equal to three times her weight at the bottom of the dip. What is her speed as she goes through the dip
Answer:
14.69
Explanation:
The circle of radius R = 11.0m
Force f = 3 times her Weight
= 3W = 3mg
Then the net force acting on her
F = W + F(centripetal)
= mg + mv²/r
= Mg + mv²/r = 3mg
Then her speed is going to be
V = √2gr
Where g =9.81m/s²
R = 11.0
When we put these values into the formula we get:
V = √2x9.81x11.0
V = √215.82
V = 14.69
A cannonball is fired at a 45.0° angle and an initial velocity of 670 m/s. Assume no air resistance. How long until the cannonball hits the ground?
96.7 s
55.3 s
65.3 s
45.5 s
Answer:
96.7 s
Explanation:
Time of flight in projectile can be calculated thus:
T = 2 × u × sin ϴ/ g
Where;
T = time of flight (s)
u = initial velocity (m/s)
ϴ = Angle of projectile (°)
g = acceleration due to gravity (9.8m/s²)
Based on the provided information; u = 670m/s, ϴ = 45°
Hence, using T = 2.u.sin ϴ/ g
T = 2 × 670 × sin 45° ÷ 9.8
T = 1340 × 0.7071 ÷ 9.8
T = 947.52 ÷ 9.8
T = 96.68
T = 96.7s
1. You are hired to lift 25 kg crates a vertically 1.0 m from the ground onto a truck. How many crates would you have to load onto the truck in 1 minute for your average power output in lifting the crates to be 110 W
Answer:
The number of crate to be lifted is 27
Explanation:
Given;
mass of the crates, m = 25 kg
height in which the crate is lifted, h = 1.0 m
power output, P = 110 W
time to complete the task, t = 1 minutes = 60 s
The input energy is equal to the gravitational energy due to height the crate is lifted is given as;
E(input) = mgh
E(input) = 25 x 9.8 x 1
E(input) = 245 J
Output energy is given as;
E(output) = P x t
E(output) = 110 x 60
E(output) = 6600 J
Let the number of crate to be lifted = n
n x E(input) = E(output)
n x 245 = 6600
n = 6600 / 245
n = 27 crates
A 5.50-kg object is hung from the bottom end of a vertical spring fastened to an overhead beam. The object is set into vertical oscillations having a period of 3.50 s. Find the force constant of the spring.
Answer:
17.71N/m
Explanation:
The period of the spring is expressed according to the expression;
[tex]T = 2 \pi \sqrt{\frac{m}{k} } \\[/tex]
m is the mass of the object
k is the force constant
Given
m = 5.50kg
T = 3.50s
Substitute into the formula;
[tex]T = 2 \pi \sqrt{\frac{m}{k} } \\3.5 = 2 (3.14) \sqrt{\frac{5.5}{k} } \\3.5 = 6.28 \sqrt{\frac{5.5}{k} } \\\frac{3.5}{6.28} = \sqrt{\frac{5.5}{k} } \\0.557 = \sqrt{\frac{5.5}{k} } \\square \ both \ sides\\0.557^2 = (\sqrt{\frac{5.5}{k} })^2 \\0.3106 = \frac{5,5}{k}\\k = \frac{5.5}{0.3106}\\k = 17.71N/m[/tex]
Hence the force constant of the spring is 17.71N/m
Determine the inductance of a solenoid with 650 turns in a length of 28 cm . The circular cross section of the solenoid has a radius of 3.5 cm .
Answer:
The value is [tex]L = 0.0073 \ H[/tex]
Explanation:
From the question we are told that
The number of turns is [tex]N = 650 \ turns[/tex]
The length is [tex]l = 28 \ cm = 0.28 \ m[/tex]
The radius of the cross-section is [tex]r = 3.5 \ cm = 0.035 \ m[/tex]
Generally the cross-sectional area is mathematically represented as
[tex]A = \pi * r^2[/tex]
=> [tex]A = 3.142 * 0.035^2[/tex]
=> [tex]A = 0.00384 \ m^2[/tex]
Generally the inductance is mathematically represented as
[tex]L = \frac{N^2 * \mu _o * A }{ l}[/tex]
Here [tex]\mu_o[/tex] is the permeability of free space with value [tex]\mu_o = 4\pi * 10^{-7} N/A^2[/tex]
=> [tex]L = \frac{ 650^2 * 4\pi * 10^{-7} * 0.00384 }{0.28}[/tex]
=> [tex]L = 0.0073 \ H[/tex]
12) You find 13,406,190 pennies. If each penny weighs 4 grams, how much did all that loot weigh in lbs.? (2.2 lbs = 1 Kilogram)
(please show work!)
Answer:
here is the answer
Explanation:
117974.472
What makes ramps useful simple machines?
By increasing the distance, the force
required decreases
b. By increasing the distance, the required
work decreases
c. By increasing the force, the required
distance decreases
Answer:
It reduces the force necessary to move a load a certain distance up by providing a path for the load to move at a low angle to the ground.
Explanation:
Clear selection
10 points
A laptop battery stores energy with an efficiency of 80%. If 16 000 J of
energy are transferred to the laptop from the battery, how much energy
must have been transferred to the battery?
20 kJ
20 J
1.28 kJ
12 800 J
Next
Page 1 of 2
Answer:
20000J or 20kJ
Explanation:
Given parameters:
Efficiency of the battery = 80%
Amount of energy transferred = 16000J
Unknown:
How much energy was transferred to the battery = ?
Solution:
Since the battery is 80% efficient, it loses 20% of energy anytime it wants to store energy.
Now, 16000J of energy is contained in the battery, the original amount of energy sent to the battery;
Let the amount of energy sent to the battery be y
80% of y = 16000
0.8y = 16000
y = 20000J or 20kJ
Find the altitude of the triangle in the figure below. Answer in units of m.
The altitude of the triangle is 10.1 m.
What is the altitude of the triangle?We can see that the triangle is a right angled triangle as we can see in the image. The altitude of the triangle is the highest point of the triangle. Let us label the angles A B C
C = 50 degrees
B = 90 degrees
A = 180 - (90 + 50) = 40 degrees
Then;
tan 40 = altitude/ 12 m
altitude = tan 40 degrees * 12 m
= 10.1 m
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