3.6 Make innovative suggestions on how you could instill healthy environmental values
in communities.
You could hold rallies which attract a lot of people, they come and you discuss apon making the world a better place and how you want to shape the society.
Consider a father pushing a child on a playground merry-go-round. The system has a moment of inertia of 84.4 kg.m^2. The father exerts a force on the merry-go-round perpendicular to its radius to achieve an angular acceleration of 4.44 rad/s^2.
Required:
a. How long (in s) does it take the father to give the merry-go-round an angular velocity of 1.53 rad/s? (Assume the merry-go-round is initially at rest.)
b. How many revolutions must he go through to generate this velocity?
c. If he exerts a slowing force of 270 N at a radius of 1.20 m, how long (in s) would it take him to stop them?
Answer:
Explanation:
Given that:
the initial angular velocity [tex]\omega_o = 0[/tex]
angular acceleration [tex]\alpha[/tex] = 4.44 rad/s²
Using the formula:
[tex]\omega = \omega_o+ \alpha t[/tex]
Making t the subject of the formula:
[tex]t= \dfrac{\omega- \omega_o}{ \alpha }[/tex]
where;
[tex]\omega = 1.53 \ rad/s^2[/tex]
∴
[tex]t= \dfrac{1.53-0}{4.44 }[/tex]
t = 0.345 s
b)
Using the formula:
[tex]\omega ^2 = \omega _o^2 + 2 \alpha \theta[/tex]
here;
[tex]\theta[/tex] = angular displacement
∴
[tex]\theta = \dfrac{\omega^2 - \omega_o^2}{2 \alpha }[/tex]
[tex]\theta = \dfrac{(1.53)^2 -0^2}{2 (4.44) }[/tex]
[tex]\theta =0.264 \ rad[/tex]
Recall that:
2π rad = 1 revolution
Then;
0.264 rad = (x) revolution
[tex]x = \dfrac{0.264 \times 1}{2 \pi}[/tex]
x = 0.042 revolutions
c)
Here; force = 270 N
radius = 1.20 m
The torque = F * r
[tex]\tau = 270 \times 1.20 \\ \\ \tau = 324 \ Nm[/tex]
However;
From the moment of inertia;
[tex]Torque( \tau) = I \alpha \\ \\ Since( I \alpha) = 324 \ Nm. \\ \\ Then; \\ \\ \alpha= \dfrac{324}{I}[/tex]
given that;
I = 84.4 kg.m²
[tex]\alpha= \dfrac{324}{84.4} \\ \\ \alpha=3.84 \ rad/s^2[/tex]
For re-tardation; [tex]\alpha=-3.84 \ rad/s^2[/tex]
Using the equation
[tex]t= \dfrac{\omega- \omega_o}{ \alpha }[/tex]
[tex]t= \dfrac{0-1.53}{ -3.84 }[/tex]
[tex]t= \dfrac{1.53}{ 3.84 }[/tex]
t = 0.398s
The required time it takes= 0.398s
With no friction, you can use the relationship between potential and kinetic energy to predict the speed of the car at the bottom of this hill from its starting height.
a. True
b. False
A tension of 35.0N is applied downward on a 2.50kg mass. What is the acceleration of the mass?
A. -59.5 m/s2
B. -14.0 m/s2
C. -4.20 m/s2
D. -23.8 m/s2
Answer:
D. -23.8 m/s2
Explanation:
Answer:
[tex]\text{B. }-14.0\:\mathrm{m/s^2}[/tex]
Explanation:
From Newton's 2nd Law, we have [tex]\Sigma F=ma[/tex].
Substituting given values, we get:
[tex]-35.0=2.50a,\\a=\frac{-35.0}{2.50},\\a=\boxed{-14.0\:\mathrm{m/s^2}}[/tex]
*Note the negative sign simply implies that the mass is travelling downwards (direction).
135g of an unknown substance gains 9133 J of heat as it is heated from 25⁰C to 100⁰C. Using the chart below, determine the identity of the unknown substance.
Answer:
The unknown substance is Aluminum.
Explanation:
We'll begin by calculating the change in the temperature of substance. This can be obtained as follow:
Initial temperature (T₁) = 25 ⁰C
Final temperature (T₂) = 100 ⁰C
Change in temperature (ΔT) =?
ΔT = T₂ – T₁
ΔT = 100 – 25
ΔT = 75 ⁰C
Finally, we shall determine the specific heat capacity of the substance. This can be obtained as follow:
Change in temperature (ΔT) = 75 ⁰C
Mass of the substance (M) = 135 g
Heat (Q) gained = 9133 J
Specific heat capacity (C) of substance =?
Q = MCΔT
9133 = 135 × C × 75
9133 = 10125 × C
Divide both side by 10125
C = 9133 / 10125
C = 0.902 J/gºC
Thus, the specific heat capacity of substance is 0.902 J/gºC
Comparing the specific heat capacity (i.e 0.902 J/gºC) of substance to those given in the table above, we can see clearly that the unknown substance is aluminum.
74Be decays with a half-life of about 53 d. It is produced in the upper atmosphere, and filters down onto the Earth's surface.
If a plant leaf is detected to have 350 decays/s of 74Be, how long do we have to wait for the decay rate to drop to 25 per second?
Answer:
201.8 days
Explanation:
The activity of a radioactive sample as a function of times is :
[tex]$R=R_0e^{\frac{0.693t}{T_{1/2}}}$[/tex]
Here, [tex]$R_0$[/tex] = the initial activity
[tex]$T_{1/2}$[/tex] = half life
t = elapsed time
Now rearranging the equation for time, t, we get:
[tex]$\frac{R}{R_0}=e^{-\frac{0.693t}{T_{1/2}}}$[/tex]
[tex]$\ln\left(\frac{R}{R_0}\right)=-\frac{0.693t}{T_{1/2}}$[/tex]
[tex]$t=\frac{-\ln\left(\frac{R}{R_0}\right)T_{1/2}}{0.693}$[/tex]
[tex]$t=\frac{-\ln\left(\frac{25}{350}\right)\times 53}{0.693}$[/tex]
= 201.8 days
Therefore, the required time is 201.8 days
A truck was carrying a substance in a tank. The molecules of that substance were moving away from each other. The truck parked overnight in a place where energy transferred out of the substance. In the morning, the substance was a gas. How were the molecules moving in the morning? Explain why the molecules were moving that way after energy was transferred out of them.
(Make it ask long as you need)
Or (short)
Answer:
In the morning the molecules were moving away from each other with a smaller speed than when the truck was carrying the substance.
Explanation:
You are designing an airplane propeller that is to turn at 2400 rpm (Fig. 9.13a). The forward airspeed of the plane is to be 75.0 m/s 75.0 m/s, and the speed of the propeller tips through the air must not exceed 270 m/s 270 m/s. (This is about 80% of the speed of sound in air. If the propeller tips moved faster, they would produce a lot of noise.) What is the maximum possible propeller radius?
Answer:
r = 1.07 m
Explanation:
The maximum radius of the propeller that can be allowed is given by the following formula:
[tex]v = r\omega\\\\r = \frac{v}{\omega}[/tex]
where,
r = maximum possible radius of the propeller = ?
v = maximum possible linear speed of the propeller = 270 m/s
ω = angular speed of the propeller = (2400 rpm)(2π rad/1 rev)(1 min/60 s)
ω = 251.33 rad/s
Therefore,
[tex]r = \frac{270\ m/s}{251.33\ rad/s}[/tex]
r = 1.07 m
Does a ball rolling on an inclined plane have the same acceleration on the way up as it does on the way down?
Answer:
No, it does not.
Explanation:
According to the Law of Gravitation, something going down has more kinetic energy than something going up because it attracts pressure from around it when going down. When it goes up, it has less gravitational force and inertia also stops the ball from rolling upward. Therefore, without the amount of kinetic energy, it will not have the same amount of acceleration.
1. In order to change the speed of a wave, you must change something about the medium. T or F
2. Diffraction is the process in which waves spread out as they pass through an opening. T or F
3. The larger the opening a wave passes through, the more the wave will diffract. T or F
Answer:
1) False
As the frequency can be defined as the number of times wave formed per unit time or in other words the numbers of a combination of a crest and trough forms. So the frequncy of a sound wave depends upon the source producing sounds
2)False
Diffraction is the process in which a light wave bends when they pass through a specified medium such as water.
3)True
hope it helps
An object is moving in a straight line at constant speed. A resultant torce begins to act upon
the object.
State the ways in which the force may change the motion of the object
Answer: The velocity magnitude or the velocity direction chages.
Explanation:
According to Newton's second law of motion, the acceleration of a system moved in same direction and is also directly proportional to the external force which acts on it while inversely proportional to the mass. The formula is: a = F/m
Based on the question, since the object obtains acceleration, then it can be infered that there will be changes in the velocity magnitude or the direction as a result of the motion.
A scientist wants to create a new material using nanotechnology. In which size range will she be working? 1 nm to 100 nm 1 to 10,000 nm 100 to 1000 nm 100 to 10,000 nm
Answer:
I believe it’s A
Explanation:
Answer:
A is correct (1 nm to 100 nm)
Explanation:
I just took the exam
At what rate is thermal energy being generated in the 2R-resistor when ε = 12 V and R = 3.0 Ω?
Answer:
6 W
Explanation:
From the given information:
The resistance in Parallel for 2R is:
[tex]R_p = \dfrac{2R\times 2R}{2R+2R} \\ \\ R_p= R[/tex]
The equivalent resistance:
[tex]R_{eq} = R_p + R = 2R[/tex]
[tex]R_{eq} = 2(3)[/tex]
[tex]R_{eq} = 6 \ \ ohms[/tex]
The current through the circuit in R is:
[tex]= \dfrac{12}{R+R} \\ \\ = \dfrac{12}{2\times 3} \\ \\ = 2 A[/tex]
The current through the circuit in 2R is:
[tex]I_2R = (2A) \times \dfrac{2R}{2R+2R}[/tex]
[tex]I_2R = 2A \times \dfrac{1}{2} \\ \\ I_2R = 1A[/tex]
Finally, the thermal energy:
[tex]P_{2R} = (1)^2 (2R)[/tex]
[tex]P_{2R} = (1)^2 (2\times 3)[/tex]
[tex]P_{2R} = 6W[/tex]
please select all that would be categorized as vectors
Answer:
1. 10 ft/s² straight up
2. 4 Km north-west
3. 20 m/s South
Explanation:
To successfully categorize the quantities given above as vectors, we must understand what vector quantity is.
A vector quantity is a quantity that has both magnitude and direction.
Considering the question given above, the vector quantities are:
1. 10 ft/s² straight up
2. 4 Km north-west
3. 20 m/s South
The remaining quantities in the question are not considered as vectors because they only have magnitude but no direction. They are therefore referred to as scalar quantities.
How does a generator use the effect you noticed in the pickup coil to generate electrical energy? What energy transformations are taking place? Why does a generator make alternating current? What change would have to be made to make direct current?
Answer:
Movement of Electrons in opposite direction of the rotation of the pickup coil leads to the direction of Electrical energy ( Alternating current ).
Explanation:
For a Generator to generate electricity, Electrons that is found in the rotating coil of the Generator will experience some sort of force that makes them to start moving in a direction that is perpendicular to the direction of the rotating/pickup coil found in the Generator.
The conversion of mechanical energy (Rotation of the pickup coil ) to electrical energy takes place in the Generator
The generator makes an alternating current because electrons move in opposite direction of the rotating coil
In other to generate a Direct current using a generator we have to replace the slip rings with commutator.
in a simple machine the input work is 187.5 N and output work is 125N. If load distance is 25 cm and effort distance is 75 cm calculate value of load and effort
Answer:
1. Laod = 500 N
2. Effort = 250 N
Explanation:
From the question given above, the following data were obtained:
Input work = 187.5 J
Output work = 125 J
Load distance = 25 cm
Effort distance = 75 cm
1. Determination of the load.
Output work = 125 J
Load distance = 25 cm = 25/100 = 0.25 m
Load =?
Output work = Load × Load distance
125 = Load × 0.25
Divide both side by 0.25
Load = 125 / 0.25
Laod = 500 N
2. Determination of the effort.
Input work = 187.5 J
Effort distance = 75 cm = 75/100 = 0.75 m
Effort =?
Input work = Effort × Effort distance
187.5 = Effort × 0.75
Divide both side by 0.75
Effort = 187.5 / 0.75
Effort = 250 N
If you make multiple measurements of your height, you are likely to find that the results vary by nearly half an inch in either direction due to measurement error and actual variations in height. You are slightly shorter in the evening, after gravity has compressed and reshaped your spine over the course of a day. One measurement of a man's height is 6 feet and 1 inch. Express his height in meters, using the appropriate number of significant figures.
Answer:
H = 1.85 m
Explanation:
First, we will convert the height completely into inches. 1 feet contains 12 inches in it. Therefore:
H = (6 feet)(12 inch/1 feet) + 1 inch
H = 73 inches
Now, we will convert this height from inches to meters. 1 inch is equivalent to 0.0254 m. Therefore:
H = (73 inches)(0.0254 m/1 inch)
H = 1.85 m
Which situation is contrary to Newton’s first law of motion?
An object at rest begins to move when an external force is applied.
A moving object has a constant velocity under the influence of balanced forces.
An object at rest stays at rest as long as unbalanced forces act on it.
A moving object slows down when an external force is applied.
Answer:
An object at rest stays at rest as long as unbalanced forces act on it.
Explanation:
Inertia can be defined as the tendency of an object or a body to continue in its state of motion or remain at rest unless acted upon by an external force.
In physics, Sir Isaac Newton's First Law of Motion is known as Law of Inertia and it states that, an object or a physical body in motion will continue in its state of motion at continuous velocity (the same speed and direction) or, if at rest, will remain at rest unless acted upon by an external force.
The inertia of a physical object such as a truck is greatly dependent or influenced by its mass; the higher the quantity of matter in a truck, the greater will be its tendency to continuously remain at rest.
Hence, the situation which is contrary to Newton’s first law of motion is that, an object at rest stays at rest as long as unbalanced forces act on it.
According to Newton’s first law of motion, an object at rest stays at rest as long as unbalanced forces do not act on it.
Answer:
yes it right
Explanation:
cat
A book is sitting on a table. The book is
applying a 65 N down on the table.
How much force is the table exerting on the
book?
Answer:
65 Newtons
Explanation:
A book is kept on the table. The book is applying 65 N of force down on the table. So the table will also apply 65 N force to the book.
What is Force?According to physics, a force is an effect that has the power to change an object's motion. A force can cause a massed item to accelerate or modify its velocity. A push or a pull is a straightforward method to explain force. Considering that a force has both a magnitude and a direction, it is a vector quantity.
The pace at which an object's direction changes when 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.
When the book is applying force on the table that is mg, and it is 65 N the table will also generate a normal reaction force which will be equal to the force applied by the book which is 65 N.
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The total resistance of a series circuit is 15.0 ohms what is the second resistance of the first resistance is 10.0 ohms?
A. less than 5.0 ohms
B. 5.0 ohms
C. 15 ohms
D. 25 ohms
What is the net force on a skydiver falling with a constant velocity of 0 m/s downward?
1. What kind of force is the force of gravity? (1 Point) contact force
non-contact force electromagnetic force imaginary force
Answer:
the answer is electromagnetic force because gravity is a force of attraction
Find the magnitude of the free-fall acceleration at the orbit of the Moon (a distance of 60RE from the center of the Earth with the radius of RE). Use the gravitational acceleration on the surface of the Earth is 9.8m/s2.
Answer:
The magnitude of the free-fall acceleration at the orbit of the Moon is [tex]2.728\times 10^{-3}\,\frac{m}{s^{2}}[/tex] ([tex]\frac{2.784}{10000}\cdot g[/tex], where [tex]g = 9.8\,\frac{m}{s^{2}}[/tex]).
Explanation:
According to the Newton's Law of Gravitation, free fall acceleration ([tex]g[/tex]), in meters per square second, is directly proportional to the mass of the Earth ([tex]M[/tex]), in kilograms, and inversely proportional to the distance from the center of the Earth ([tex]r[/tex]), in meters:
[tex]g = \frac{G\cdot M}{r^{2}}[/tex] (1)
Where:
[tex]G[/tex] - Gravitational constant, in cubic meters per kilogram-square second.
[tex]M[/tex] - Mass of the Earth, in kilograms.
[tex]r[/tex] - Distance from the center of the Earth, in meters.
If we know that [tex]G = 6.674\times 10^{-11}\,\frac{m^{3}}{kg\cdot s^{2}}[/tex], [tex]M = 5.972\times 10^{24}\,kg[/tex] and [tex]r = 382.26\times 10^{6}\,m[/tex], then the free-fall acceleration at the orbit of the Moon is:
[tex]g = \frac{\left(6.674\times 10^{-11}\,\frac{m^{3}}{kg\cdot s^{2}} \right)\cdot (5.972\times 10^{24}\,kg)}{(382.26\times 10^{6}\,m)^{2}}[/tex]
[tex]g = 2.728\times 10^{-3}\,\frac{m}{s^{2}}[/tex]
The yearly whole-body dose caused by radioactive 40K absorbed in our tissues is 17 mrem. Note: 40K also emits gamma rays, many of which leave the body before being absorbed. Because fatty tissue has low potassium concentration and muscle has a higher concentration, gamma ray emissions indicate indirectly a person's fat content. Assuming that 40K undergoes beta decay with an RBE of 1.4 , determine the absorbed dose in rads. How much beta ray energy does an 75-kg person absorb in one year? Use that 1rad=10^−2J/kg .
Answer:
The beta ray Energy (E) absorbed = 0.009105 Joules
Explanation:
The absorbed dose rate in the tissue can be determined by using the known formula:
Dose equivalent = absorbed dose × relative biological effective (RBE)
[tex]absorbed \ dose = \dfrac{Dose \ equivalent}{RBE}[/tex]
[tex]absorbed \ dose = \dfrac{17 \times 10^{-3} \ rem}{1.4}[/tex]
absorbed dose = 12.14 × 10⁻³ rad
absorbed dose = 12.14 m rad
However, since the absorbed dose is determined, the energy absorbed in one year is can be expressed as:
Energy (E) = mass × absorbed rate
Energy (E) = 75 kg × 12.14 × 10⁻³ rad
Energy (E) = 75 kg × 12.14 × 10⁻³× 10⁻² J/kg
Energy (E) = 75 × 12.14 × 10⁻³× 10⁻² Joules
Energy (E) = 0.009105 Joules
Which of the following does not represent a significant negative environmental impact of using nuclear fuel? a. air pollution b. mining c. radiation d. waste production Please select the best answer from the choices provided A B C D
A significant negative environmental impact of using nuclear fuel is mining. The correct option is b.
What is mining?Mining is the process or industry of obtaining coal or other minerals from a mine.
Using nuclear fuels for mining will have no negative impact on the environment. All other terms represent negative impact of nuclear fuel Thus, The correct option is b.
Learn more about mining.
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What is the definition of Heat Transfer
Answer:
Heat transfer is an engineering discipline that concerns the generation, use, conversion, and exchange of heat (thermal energy) between physical systems.
Explanation:
Answer:
Heat transfer is a discipline of thermal engineering that concerns the generation, use, conversion, and exchange of thermal energy between physical systems. Heat transfer is classified into various mechanisms, such as thermal conduction, thermal convection, thermal radiation, and transfer of energy by phase changes.
Explanation:
hope that helps
When two charged particles are moving toward each other, their velocities decrease until they eventually come to a
stop. What happens afterward? (1 point)
O They remain in the same place without moving.
O They accelerate toward each other.
O they bond and accelerate together.
O They accelerate in opposite directions.
When two charged particles are moving toward each other, they bond and accelerate together.
To find the correct statement among all the options, we need to know about electromagnetic force.
What is electromagnetic force?The force between any two dynamic charged particles is the electromagnetic force. It's a combination of electric force and magnetic force. What does happen, when two charged particles move towards each other?When two charged particles move towards each other, they combine with each other dur to the electromagnetic force. Then they are travelled together as a single particle along the direction of more acceleration.Thus, we can conclude that the option (C) is correct.
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If a car has a force of 900 N and has a mass of 650 kg. What would be the acceleration of the
car as it moves down the street?
Magnets on the tracks
How can levitating trains support the claim that magnetic fields exist between objects exerting magnetic force on each other even when there is no physical contact?
Answer:
Explanation: They levitate sort of because when to opposite forces of magnets cant go together they repelThe Nardo ring is a circular test track for cars. It has a circumference of 12.5 km. Cars travel around the track at a constant speed of 100 km/h. A car starts at the easternmost point of the ring and drives for 30 minutes at this speed.
Required:
a. What distance, in km, does the car travel?
b. What is the magnitude of the car's displacement, in km, from its initial position?
c. What is the speed of the car in m/s?
Answer: 50 km, 0, 27.78 m/s
Explanation:
Given
Circumference of the track is [tex]12.5\ km[/tex]
Speed of car is [tex]100\ km/h[/tex]
Car drives for [tex]30\ \text{minute}\ or\ 0.5\ hr[/tex]
(a)Distance traveled is
[tex]\Rightarrow D=100\times 0.5\\\Rightarrow D=50\ km[/tex]
(b)displacement of the car
It can be observed that 12.5 is a multiple of 50, that is, 50 km can be interpreted as 4 complete rounds of the track.
Therefore, the displacement of the car is zero.
(c)To convert kmph to m/s, multiply the entity by [tex]\frac{5}{18}[/tex]
[tex]\Rightarrow 100\times \dfrac{5}{18}\\\\\Rightarrow 27.78\ m/s[/tex]