An electric circuit board is to be cooled by forced convection through cooling fins. Heat of 100W needs to be removed from this board from a maximum temperature of 40 degree Celsius above the room air temperature of 20 degree Celsius. The forced convection heat transfer coefficient is 355W/(m2K). Determine the required surface area of the fins. ANSWER IN m2
Answers
Answer:
\(A = 0.00704 m^2\)
Explanation:
Amount of heat to be removed, \(\dot{Q} = 100 W\)
Change in temperature, \(\triangle T = 40^0 C\)
The room air temperature, \(T_1 = 20^0C\)
The forced convection heat transfer coefficient, h = 355 W/(m²K)
Required surface area of the fins, A = ?
Given all the above parameters, the surface area of the fins is given by the formula:
\(A = \frac{\dot{Q}}{h * \triangle T} \\\\A = \frac{100}{355 * 40}\\\\A = 0.00704 m^2\)
Related Questions
A net force of 275 N accelerates a 18.0 kg mass. What is the resulting acceleration? (5 points)
Answers
Answer:
The answer is 15.28 m/s²Explanation:
The acceleration of an object given it's mass and the force acting on it can be found by using the formula
\(a = \frac{f}{m} \\ \)
where
m is the mass
f is the force
We have
\(a = \frac{275}{18} \\ = 15.277777...\)
We have the final answer as
15.28 m/s²Hope this helps you
FIGURE 1 shows a 10 kg uniform metal rod with 2.0 m long pivoted at its centre C. A 20 N force is exerted on the rod 0.5 m from point C. If the rod is in equilibrium determine the
a) force F needed
b ) magnitude and the direction of the force exerted at point C
Answers
Answer:
.38
Explanation:
According to the graph, the average acceleration of the car from 0.0 s to 40.0 s is
a. 2.0 m/s²
C.3.5 m/s²
b. -2.5 m/s²
d.2.5 m/s²
Answers
The acceleration of the object is 2.5 m/s^2
What is acceleration?The idea that should be at the back of your mind when you hear the use of the term acceleration is the change in the velocity of the object with respect to the time.
In this case, we have to look at the graph that we have been given in the question. It is a graph of the velocity against the time and the slope of the graph is the acceleration of the motion that is under consideration.
a = 100 - 0/40 - 0
= 2.5 m/s^2
We have the acceleration as 2.5 m/s^2
Learn more about acceleration:https://brainly.com/question/12550364
#SPJ1
the flux through the coils of a solenoid changes from 6.78*10^-4 wb to 1.33*10^-4 wb in 0.0333 s if the solenoid has 605 loops how much emf is generated
Answers
The electric and magnetic field ( emf ) generated given the number of loops in the solenoid is 9.90 V.
Given the data in the question;
\(\delta \theta_1 = 6.78*10^{-4}Wb\)\(\delta \theta_2 = 1.33*10^{-4}Wb\)\(\delta t = 0.0333s\)\(N = 605\)Electric and magnetic fields (EMF)
Emf are invisible energy regions also called radiation, associated with the use of electrical power and various forms of lighting.
From Faraday's law; emf E is expressed as;
\(emf = -N\frac{\delta \theta }{\delta t}\)
Where N is number of loops, \(\delta \theta\) is change in magnetic flux ( \(\delta \theta_2 - \delta \theta_1\) ) and \(\delta t\) is change in time.
First we determine the change in flux through each loop;
\(\delta \theta\) = ( \(\delta \theta_2 - \delta \theta_1\) )
\(\delta \theta = (1.33 * 10^{-4} Wb) - (6.78 * 10^{-4} Wb)\\\\\delta \theta = -0.000545\)
Now, we substitute our values into the expression above
\(emf = -N\frac{\delta\theta}{\delta t} \\\\emf = (-605) * (\frac{-0.000545}{0.0333}) \\\\emf = (-605) * (-0.016366)\\\\emf = 9.90V\)
Therefore, the electric and magnetic field ( emf ) generated given the number of loops in the solenoid is 9.90 V.
Learn more about electric and magnetic field emf: https://brainly.com/question/23765088
what is the most effortless walking speed for a person with 90cm long legs if the length of each step is 90cm
Answers
Answer:
75 cm/second.
Explanation:
Formula:
Walking speed = stride length / time per step
Walking speed = 90cm/time per step
= 90cm/1.2 seconds (a common estimate time per step)
= 75cm/second.
A 3 Volt battery is connected in series to three resistors: 4,6, and 2. Find the total resistance.
Answers
Answer:
The same current flows through each resistor in series. Individual resistors in series do not get the total source voltage, but divide it. The total resistance in a series circuit is equal to the sum of the individual resistances: RN(series)=R1+R2+R3+…
The kinetic energy of an object is equal to one half Its mass multiplied by its
speed
A squared
B cubed
C to the fourth power
D to the fifth power
Answers
The figure shows a jet engine suspended beneath the wing of an airplane. The weight of the engine is 14900 N and acts as shown in the figure. In flight the engine produces a thrust of 61500 N that is parallel to the ground. The rotational axis in the figure is perpendicular to the plane of the paper. With respect to this axis, find the magnitude of the torque due to (a) the weight and (b) the thrust.
Answers
We have that for the Question, it can be said that With respect to this axis, the magnitude of the torque due to the weight and ,the thrust is
TW=19740N-mTT=130387.39N-mFrom the question we are told
The figure shows a jet engine suspended beneath the wing of an airplane. The weight of the engine is 14900 N and acts as shown in the figure. In flight the engine produces a thrust of 61500 N that is parallel to the ground. The rotational axis in the figure is perpendicular to the plane of the paper. With respect to this axis, find the magnitude of the torque due to (a) the weight and (b) the thrust.
a)
Generally the equation for the Torque due to weight is mathematically given as
\(TW=Engine weight*2.50*sin32\\\\TW=14900*2.50*sin32\)
TW=19740N-m
b)
Generally the equation for the Torque due to thrust is mathematically given as
\(TT=Engine thrust*2.50*cos32\\\\TT=61500*2.50*cos32\\\\\)
TT=130387.39N-m
For more information on this visit
https://brainly.com/question/23379286
03.03 LC)
The refraction of a sound wave occurs when the sound wave
stops at a boundary between media
bounces off the boundary between media
bends as it passes through the boundary between media
changes frequency after it passes through the boundary between media
Answers
The refraction of a sound wave occurs when the sound wave bends as it passes through the boundary between media. Refraction occurs when there is a difference in the speed of sound waves in two different media.
The bending of the sound wave occurs because the speed of sound changes as it passes from one medium to another. The amount of bending depends on the angle of incidence and the difference in speed between the two media. If the speed of sound is higher in the second medium than the first, then the wave bends away from the normal. If the speed of sound is lower in the second medium than the first, then the wave bends towards the normal. If the sound wave is incident perpendicular to the boundary, then there is no bending of the wave and no refraction occurs. Refraction of sound waves is an important phenomenon in our daily lives. It is the reason why we can hear sound around corners or why we can hear someone talking in another room even if the door is closed. The refraction of sound waves is also used in medical imaging, such as in ultrasound, where the sound waves are refracted as they pass through different tissues in the body.For more such questions on sound wave, click on:
https://brainly.com/question/16093793
#SPJ8
When using a stream table in a classroom setting what are three factors that can be controlled?
Answers
Answer:
These include the slope of the land, the nature of the land surface, the placement of dams, and the direction of topsoil disturbance as created by farming activities. Materials: Students should work in groups of 3 or 4, or as materials allow.Explanation:
Hope this helpsTwo lenses have exactly the same curvature on both sides, and yet they refract light differently. Which of the following could explain this?A.Lens A and lens B are made from two different materials with different optical properties.B.While the angle of refraction is set by the curvature, whether the light refracts toward or away from the axis is random.C.Lens A was facing with its more curved side facing the incident light, and lens B was turned the other way.D.The curvature of the lenses does not determine how the lenses refract light.
Answers
Let's check the formula for a focal length:
\(\frac{1}{f}=(n-1)(\frac{1}{R1}-\frac{1}{R2}+\frac{(n-1)d}{nR1\cdot R2}\)Since basically the two lenses have the same form, we can conclude that R1,R2 and d are the same. But n ( refractive index) could be different. n depends on the material, so we can conclude that the answer is:
A.
Lens A and lens B are made from two different materials with different optical properties.
What is the amount of thermal energy needed to make 5 kg of ice at - 10 °C to
steam at 100 °C? (Heat of fusion of Ice is 3.34 x 10 j/kg, specific heat capacity of
ice is 2.09 x 10 3 J/kg °C, Specific heat capacity of water is 4.186 x 10 ? J/kg° C,
Heat of vaporization of water 2.26 x 10 J/kg)
Answers
Answer:
The amount of thermal energy needed is 15167500 joules.
Explanation:
By First Law of Thermodynamics, we see that amount of thermal energy (\(Q\)), in joules, is equal to the change in internal energy. From statement we understand that change in internal energy consisting in two latent components (\(U_{l,ice}\), \(U_{l,steam}\)), in joules, and two sensible component (\(U_{s,w}\)), in joules, that is:
\(Q = U_{l,ice} + U_{s, w} + U_{s,ice} + U_{l,steam}\) (1)
By definitions of Sensible and Latent Heat, we expanded the formula:
\(Q = m\cdot (h_{f,w}+h_{v,w}+c_{ice}\cdot \Delta T_{ice}+c_{w}\cdot \Delta T_{w})\) (2)
Where:
\(m\) - Mass, in kilograms.
\(h_{f,w}\) - Latent heat of fussion of water, in joules per kilogram.
\(h_{v,w}\) - Latent heat of vaporization of water, in joules per kilogram.
\(c_{ice}\) - Specific heat of ice, in joules per kilogram per degree Celsius.
\(c_{w}\) - Specific heat of water, in joules per kilogram per degree Celsius.
\(\Delta T_{ice}\) - Change in temperature of ice, measured in degrees Celsius.
\(\Delta T_{w}\) - Change in temperature of water, measured in degrees Celsius.
If we know that \(m = 5\,kg\), \(h_{f,w} = 3.34\times 10^{5}\,\frac{J}{kg}\), \(h_{v,w} = 2.26\times 10^{6}\,\frac{J}{kg}\), \(c_{ice} = 2.090\times 10^{3}\,\frac{J}{kg\cdot ^{\circ}C}\), \(c_{w} = 4.186\times 10^{3}\,\frac{J}{kg\cdot ^{\circ}C}\), \(\Delta T_{ice} = 10\,^{\circ}C\) and \(\Delta T_{w} = 100\,^{\circ}C\), then the amount of thermal energy is:
\(Q = 15167500\,J\)
The amount of thermal energy needed is 15167500 joules.
The musical note A above middle C has frequency of 440Hz. What is the wavelength of the sound produced
Answers
Answer:
These destructive frequencies entrain the thoughts towards disruption, disharmony, and disunity. Additionally, they also stimulate the controlling organ of the body — the brain — into disharmonious resonance, which ultimately creates disease and war.
=0.795 meter
as the distance between 2 objects increased, the gravitational force between them
Answers
Answer:
Becomes weaker
Explanation:
Hope this helps :)
A baseball is thrown at an angle of 25 degrees relative to the ground at a speed of 23 m/s. If the ball was caught 42 m from the thrower:
What is the initial vertical velocity?
What is the initial horizontal velocity?
How long was it in the air?
How high did the ball travel before being caught?
Answers
Answer:
a) \( v_{0y} = 9.72 m/s \)
b) \( v_{0x} = 20.85 m/s \)
c) \( t = 2.01 s \)
d) \( h_{max} = 4.82 m \)
Explanation:
a) The initial vertical velocity is given by:
\( v_{0y} = v*sin(\theta) \)
Where:
θ: 25°
v: is the magnitude of the speed = 23 m/s
\( v_{0y} = 23 m/s*sin(25) = 9.72 m/s \)
b) The initial horizontal velocity can be calculated as follows:
\( v_{0x} = v*cos(\theta) = 23 m/s*cos(25) = 20.85 m/s \)
c) The flight time can be calculated using the following equation:
\( v_{0x} = \frac{x}{t} \)
Where:
x: is the total distance = 42 m
\( t = \frac{x}{v_{0x}} = \frac{42 m}{20.85 m/s} = 2.01 s \)
d) The maximum height is given by:
\( v_{fy}^{2} = v_{0y}^{2} - 2gh_{max} \)
Where:
\( v_{fy}\): is the final vertical velocity =0 (at the maximum heigth)
g: is the gravity = 9.81 m/s²
\(h_{max} = \frac{v_{0y}^{2}}{2g} = \frac{(9.72 m/s)^{2}}{2*9.81 m/s^{2}} = 4.82 m\)
I hope it helps you!
Given a→=3i^+4j^-k^ and b→=i^-3j^+k^, find a unit vector n^ normal to the plane containing a→ and b→ such that a→, b→ and n^ in that order form a right-handed system.
Select one:
n^=i^-4j^+13k^186
n^=i^-4j^-13k^186
n^=i^+4j^-13k^186
n^=i^+4j^+13k^186
Answers
The unit vector normal to the plane is determined as (i - 4j - 13k) / √186.
Option B.
What is the unit vector n^ normal to the plane?The magnitude of the cross product of a→ and b→, is determined as follows;
|a→ × b→| = (3i +4j -k) × (i- 3j + k )
= [i j k]
[3 4 -1]
[1 -3 1]
The cross product of the vectors is calculated as follows;
= i (4 - 3) - j(3 - - 1) + k (-9 - 4)
= i - 4j - 13k
The magnitude of the vector is calculated as follows;
|n| = √ (1² + 4² + 13²)
|n| = √186
The unit vector normal to the plane is calculated as follows;
n = (i - 4j - 13k) / √186
Thus, the unit vector normal to the plane is determined as (i - 4j - 13k) / √186. The answer is B.
Learn more about unit vector here: https://brainly.com/question/17271641
#SPJ1
A milliammeter whose resistance is 120 ohm has full scale deflection with a current of 5mA. How will you use it to measure a maximum current of 100 A
Answers
Answer:
If 99.995 A pass thru a shunt and 5 mA pass thru the meter, the meter will have full scale deflection for a current of 100 A.
By Ohm's Law
99.995 Rs = .005 Rm
Rs = .005 / 99.995 * 120
Rs = .006 ohms
Using a shunt resistance of .006 Ω will produce the required result.
The value of the shunt resistor should be very low to divert most of the current, use a shunt resistor with a value of 0.0012 ohms.
The value of the shunt resistor (Rs) is:
Rs = (Rm × Im) ÷ (If - Im)
where:
Rs = Shunt resistor value
Rm = Resistance of the milliammeter
Im = Full-scale current of the milliammeter
If = Maximum current we want to measure
The shunt resistor value:
Rs = (120 × 5 ) ÷ (100 - 5)
Rs = (0.12 ) ÷ (100 - 0.005)
Rs = 0.12 ÷ 99.995
Rs = 0.00120018 ohms
Since the value of the shunt resistor should be very low to divert most of the current, use a shunt resistor with a value of 0.0012 ohms.
To know more about the shunt resistor:
https://brainly.com/question/34468136
#SPJ7
When an object is raised vertically, work is done against __________. What one word completes the sentence?
please help quickly!!
Answers
When an object is raised vertically, work is done against _gravitational force _________
What is gravitational force ?The force of attraction between all masses in the universe; especially the attraction of the earth's mass for bodies near its surface is called gravitational force .
On every body there is a force acting named gravitational force which attracts the body downward .
If a object / body is thrown up it always comes downward if only gravitational force is acting on it which act due to earth's gravity .
When an object is raised vertically, work is done against _gravitational force _________
learn more about gravitational force :
https://brainly.com/question/12528243?referrer=searchResults
#SPJ2
Which frequency would be the third harmonic in a series for an open-pipe resonator if the fundamental is 440 Hz?1) 3080 Hz2) 2200 Hz3) 1320 Hz4) 660 Hz
Answers
ANSWER
\(3)1320Hz\)EXPLANATION
To find the frequency of the third harmonic for an open-ended pipe, we apply the formula for the frequency of harmonics for open-ended pipes:
\(f=nf_o\)where fo = fundamental frequency; n = nth harmonic
Therefore, the frequency of the third harmonic is:
\(\begin{gathered} f=3\cdot440 \\ f=1320Hz \end{gathered}\)The answer is the 3rd option.
If you feel pain during weight training, what should you do?
Answers
Answer:
Explanation:
Stop. Take a 5-10 minute breather, stretch out like you're doing your pre-workout (warmups). Drink some water, lay down for 3 minutes.
Answer: I hope this helps you
Explanation:
If you experience pain during weight training, it’s important to stop the exercise immediately and assess the source of the pain. If the pain is localized and mild, you can try taking a short break and then continuing with a lighter weight or modified exercise. However, if the pain is severe or spreading, you should stop the workout altogether and seek medical attention as soon as possible. Remember to always listen to your body and use proper form and technique to prevent injury.
three identical resistors are connected in series to an ideal battery of 12 v. the current which flows through the battery is measured to be 1 a.
Answers
Each resistor has a resistance of 4 Ω.
Using Ohm's law, the voltage drop across each resistor is equal to the product of the current and resistance: V = IR
Since the resistors are identical and connected in series, the total resistance is three times the resistance of each resistor, i.e., R_total = 3R. Therefore, the voltage drop across the three resistors is:
V_total = IR_total = I(3R) = 3IR
Since the battery voltage is 12 V, the voltage drop across the resistors must add up to 12 V:
V_total = 3IR = 12 V
Substituting the given value for the current, we obtain:
3R = 12 Ω
Solving for R, we get:
R = 4 Ω
To Know more about resistor, here
https://brainly.com/question/15522393
#SPJ4
--The complete question is, Three identical resistors are connected in series to an ideal battery of 12 v. the current which flows through the battery is measured to be 1 A. Find the value of resistance.--
A sample of metal with a specific heat capacity of 0.50 kk/kg.•c Is heated to 98 degrees c and then placed in an 0.055 kg sample of water at 22 degrees C
Answers
Answer:
We must identify the heat transfers that are happening here.
One is the heat transferred from the metal as it cools (
q
1
).
The second is the heat transferred to the water as it warms (
q
2
).
Per the Law of Conservation of Energy, the sum of the two heat transfers must be zero.
Explanation:
A loudspeaker of mass 15.0 kg is suspended a distance of h = 1.00 m below the ceiling by two cables that make equal angles with the ceiling. Each cable has a length of l = 2.70 m .
1. What is the tension T in each of the cables?
Use 9.80 m/s2 for the magnitude of the free-fall acceleration.
Answers
Answer:
To solve the problem, we use the equations of equilibrium to find the tension in each cable holding up the loudspeaker. Since the loudspeaker is in equilibrium, the sum of the forces acting on it is zero. The weight of the loudspeaker is calculated first, and then we use trigonometry to find the horizontal and vertical components of the tension in one of the cables. We then apply the equation of equilibrium in the y direction to find the tension in each cable. The final answer is that the tension in each cable is approximately 81.1 N, which balances the weight of the loudspeaker.
___
Given:
Mass of loudspeaker (m) = 15.0 kg
Distance from ceiling (h) = 1.00 m
Length of cable (l) = 2.70 m
Acceleration due to gravity (g) = 9.80 m/s^2
Weight of loudspeaker:
Fg = mg
Fg = (15.0 kg)(9.80 m/s^2)
Fg = 147 N
Horizontal and vertical components of tension in one cable:
sinθ = h/l
sinθ = 1.00 m / 2.70 m
θ = sin^(-1)(1.00/2.70)
θ ≈ 21.6°
T_x = T sinθ
T_y = T cosθ
where T is the tension in the cable.
Equation of equilibrium in y direction:
ΣF_y = 2T cosθ - Fg = 0
Solving for T:
2T cosθ = Fg
T = Fg / (2 cosθ)
Plugging in the values:
T = (147 N) / (2 cos(21.6°))
T ≈ 81.1 N
What is the Mass of a 80 n dog
Answers
Answer:
80 n
Explanation:
A bicycle has a momentum of 36 kg•m/s and a velocity of 4 m/s. What is the mass of the bicycle?
Answers
Answer:
45kw45_32+675&453try to get it done
Answer:
A: 9 kg
Explanation:
on edge! hope this helps!!~ ∩(︶▽︶)∩
3. What size stars typically leave behind a neutron star?
Any star with a mass greater than 20 solar masses leaves behind a neutron star.
O Stars that are approximately 2 to 7 solar masses leave behind neutron stars.
O Any star less than 8 solar masses leaves behind a neutron star.
Stars that are approximately 8 to 20 solar masses leave behind neutron stars.
Answers
Stars that are approximately 8 to 20 solar masses leave behind neutron stars.
What is neutron star?
A neutron star is a highly compact and dense object that is created when a massive star undergoes a supernova explosion and its core collapses. It is composed almost entirely of neutrons, hence the name "neutron" star. The gravitational force of a neutron star is so strong that it compresses its mass into a very small volume, typically about 10 kilometers (6.2 miles) in radius.
Neutron stars are formed when a massive star undergoes a supernova explosion, and the core of the star collapses under its own gravity. The minimum mass of a star that can form a neutron star is about 8 solar masses, while the maximum mass is thought to be around 20-25 solar masses.
Stars with masses greater than 20-25 solar masses are expected to collapse into black holes instead of neutron stars. Therefore, option A is incorrect. Stars with masses less than 8 solar masses are not massive enough to undergo supernova explosions, and they typically end their lives as white dwarfs. Option C is therefore also incorrect.
Thus, option D is the correct answer, as stars that are approximately 8 to 20 solar masses leave behind neutron stars.
To know more about mass visit:-
https://brainly.com/question/86444
#SPJ1
The size of stars that typically leave behind a neutron star depends on their mass. Neutron stars are formed as the result of a supernova explosion of a massive star, where the core of the star collapses and forms a highly dense, compact object.
How does the neutron star formed ?According to current models, any star with a mass greater than 20 solar masses will undergo a supernova explosion and leave behind a neutron star.
However, stars with masses between 8 and 20 solar masses can also form neutron stars, depending on their composition and other factors. In general, O-type stars that are approximately 2 to 7 solar masses are more likely to form neutron stars compared to other types of stars.
On the other hand,
stars with masses less than 8 solar masses are not massive enough to undergo a supernova explosion and form a neutron star. Instead, they typically end their lives as white dwarfs or low-mass black holes. Overall, the size of stars that leave behind a neutron star depends on their mass, with the most massive stars being the most likely to form neutron stars.
To know more about supernova explosion , visit :
https://brainly.com/question/14018571
#SPJ1
A machine has a velocity ratio of 5 and the efficiency is 80% what effort would be needed to lift a load of 200N
Answers
Explanation:
To determine the effort needed to lift a load of 200N, given a velocity ratio of 5 and an efficiency of 80%, we can use the formula:
Efficiency = (Output Work / Input Work) * 100
Efficiency can also be calculated as the ratio of the output force to the input force. In this case, the output force is the load being lifted (200N), and the input force is the effort required.
Given that the velocity ratio is 5, it means that for every 5 units of distance the effort moves, the load moves 1 unit of distance. This implies that the effort is exerted over a greater distance than the load.
Let's denote the effort force as "E" and the distance moved by the effort as "dE." Similarly, the load force is "L," and the distance moved by the load is "dL."
Using the velocity ratio, we have the following relationship:
dE / dL = 5
Now, we can calculate the input work (Wi) and the output work (Wo):
Input Work (Wi) = Effort (E) * Distance moved by the effort (dE)
Output Work (Wo) = Load (L) * Distance moved by the load (dL)
Given that the efficiency is 80%, we can rewrite the formula for efficiency as:
0.80 = (Wo / Wi) * 100
Now, let's solve for the effort (E) using the given values:
Load (L) = 200N
Efficiency = 0.80
Velocity Ratio = 5
First, calculate the output work (Wo):
Wo = Load (L) * Distance moved by the load (dL)
Since the velocity ratio is 5, the distance moved by the load (dL) will be 1/5 of the distance moved by the effort (dE):
dL = (1/5) * dE
Wo = L * (1/5) * dE
Wo = 200N * (1/5) * dE
Wo = 40N * dE
Next, calculate the input work (Wi):
Wi = Effort (E) * Distance moved by the effort (dE)
Wi = E * dE
Now, substitute the values into the efficiency formula:
0.80 = (Wo / Wi) * 100
0.80 = (40N * dE) / (E * dE) * 100
0.80 = 40 / E * 100
0.80 * E = 40
E = 40 / 0.80
E = 50N
Therefore, the effort needed to lift a load of 200N with a velocity ratio of 5 and an efficiency of 80% is 50N.
You can run 9.8 m/s , 20% faster than your brother.
How much head start should you give him in order to have a tie race over 150 m ?
Express your answer to two significant figures and include the appropriate units.
Answers
You must give your brother a 3.05 seconds hear start.
Explanation:1. Find out how fast is your brother.
If you are 20% faster than your brother, it means that when you divide your speed by the speed of your brother, the result if 1.2. Let x be the speed of your brother. Hence:
\(\frac{9.8}{x} =1.2\\ \\\frac{x}{9.8} =\frac{1}{1.2} \\ \\x=\frac{9.8}{1.2} \\ \\x=8.17\)
2. Find an equation of your velocity.
Let D(t) be the distance you travel.
Let x be the time is takes to travel that distance.
Hence, your distance, with respect to time, is given by:
\(D(t)=9.8(t)\)
3. Find an equation of your brother's velocity.
Let D(t) be the distance you travel.
Let x be the time is takes to travel that distance.
Hence, your brother's distance, with respect to time, is given by:
\(D(t)=8.17(t)\)
4. Find out in how much time each person covers the 150 m.
a. Your time.
\(9.8t=150=\\ \\t=\frac{150}{9.8}=\\\\ t=15.31\)
b. Your brother's time.
\(8.17t=150=\\ \\t=\frac{150}{8.17}=\\\\ t=18.36\)
5. Find the difference in times.
Δt= 18.36-15.31= 3.05 seconds.
6. Express your answer.
You must give your brother a 3.05 seconds hear start.
-------------------------------------------------------------------------------------------------------
If you would to express the answer in meters, do the following:
\(d=8.17(3.05)=\\ \\d=24.91 m\)
Hence, you should give your brother a 24.91 meter head start.
WHAT IS ENERGY AND HOW WE USE
ENERGY
Answers
Heather and Matthew take 45 s to walk eastward along a straight road to a store 72 m away. What is their average velocity?
Answers
Answer:
v = 1.6 m/s
Explanation:
Given that,
Distance, d = 72 m
Time taken, t = 45 s
We need to find their average velocity. Average velocity of an object is given by total distance divided by total time taken.
\(v=\dfrac{d}{t}\\\\v=\dfrac{72\ m}{45\ s}\\\\v=1.6\ m/s\)
So, their average velocity is 1.6 m/s.