Complete Question:
A long distance runner running a 5.0km track is pacing himself by running 4.5km at 9.0km/hr and the rest at 12.5km/hr. What is the average speed?
Answer:
Average speed = 9.7333 km/h
Explanation:
Let the total distance be divided into A and B.Given the following data;
Total distance = 5 kmDistance A = 4.5 kmSpeed A = 9.5 km/hrSpeed B = 12.5 km/hrTo find the average speed;
First of all, we would determine the time taken to cover distance A in speed A by using the formula;
[tex] Time \ A = \frac {Distance \; A}{Speed \; A} [/tex]
Substituting the values into the formula, we have;
[tex] Time \ A = \frac {4.5}{9.5} [/tex]
Time A = 0.4737 hours
Total distance = distance A + distance B
5 = 4.5 + distance B
Distance B = 5 - 4.5
Distance B = 0.5 Km
Next, we would determine the time to cover distance B in speed B;
[tex] Time \ B = \frac {0.5}{12.5} [/tex]
Time A = 0.04 hours
Total time = time A + time B
Total time = 0.4737 + 0.04
Total time = 0.5137 hours
Now, we would solve for the average speed;
Mathematically, the average speed of an object is given by the formula;
[tex] Average \; speed = \frac {total \; distance}{total \; time} [/tex]
[tex] Average \; speed = \frac {5}{0.5137} [/tex]
Average speed = 9.7333 km/h
A 550N object has a coefficient of .012 against a smooth surface. What
force is needed to keep the object sliding?(ANSWER to 1 decimal place, no
units)
Vertically, the object is in equilibrium, so that the net force in this direction is
∑ F (vertical) = n - mg = 0
where n is the magnitude of the normal force due to the contact between the object and surface. You're given that the object's weight is mg = 550 N, so n = 550 N as well.
Horizontally, the net force would be
∑ F (horizontal) = p - f = 0
where p is the magnitude of the applied force and f is the magnitude of (kinetic) friction opposing p. Now,
f = 0.012n = 0.012 (550 N) = 6.6 N
so that you need to apply a force of p = 6.6 N to keep the object sliding at a steady pace.
People who get population education are also aware of health issues and environment education justify
Two forces of equal magnitude F
have a resultant of the same
magnitude F. The angle between the
two forces is
45°
120°
O 60°
O 35°
Answer:
the ans is 120 degree hope it will help
What is the relation between the weight of a body and acceleraton due to gravity?
Answer:
All objects on Earth, regardless of their mass, accelerate due to gravity at the same rate - that is, 9.8 m/sec2. The weight of an object can be calculated using the formula for force - F = m * a - where F equals the weight of the object and now the acceleration (a) is the acceleration of gravity (g).
the value of 1.0004 to the power 1 by 2 using Binomial approximation is
Given:
The given value is [tex](1.0004)^{\frac{1}{2}}[/tex].
To find:
The value of the given expression by using the Binomial approximation.
Explanation:
We have,
[tex](1.0004)^{\frac{1}{2}}[/tex]
It can be written as:
[tex](1.0004)^{\frac{1}{2}}=(1+0.0004)^{\frac{1}{2}}[/tex]
[tex](1.0004)^{\frac{1}{2}}=1+\dfrac{1}{2}\times 0.0004[/tex] [tex][\because (1+x)^n=1+nx][/tex]
[tex](1.0004)^{\frac{1}{2}}=1+0.0002[/tex]
[tex](1.0004)^{\frac{1}{2}}=1.0002[/tex]
Therefore, the approximate value of the given expression is 1.0002.
Which of the following is true of highly conductive elements?
Answer:
A
Explanation:
i think a is the answer because if you take an example of group 1 and 2 metals on the periodic table you will notice that they are highly reactive but they have a few electrons in their outer most shells.
I hope this helps
Explain why a person travelling in a bus falls forward when bus stops suddenly
Answer:
Cause of Inertia of Motion
Explanation:
It can be explained as follows...when the moving bus suddenly stops, the lower part of the body of the passenger contact with the bus suddenly comes to rest while the upper part of the body tends to retain its state of motion due to inertia. As a result, the passenger is thrown forward.
Si la fuerza de fricción cinetica es 250N ¿Qué fuerza se necesita para mantener a la caja deslizándose a una velocidad constante ¿
Answer:
250N
Explanation:
According to newton second law,
\sumF = ma
Fm - Ff = ma
Since the velocity is constant, a = 0m/s
Frictional force Ff = 250N
Substitute
Fm - 250 = m(0)
Fm - 250 = 0
Fm = 250N
Hence the force to keep the box sliding at constant speed is 250N
The question is given in the picture below.... please help me and mention all the steps..
Answer:
a)water is turning into ice it is changing it's state from liquid to solid
b)B to C ice is melting and it is changing it's state from solid to liquid
C to D water is boiling and it is changing it's state from liquid to vapours(steam)
c) temperature
At A 0
At B 0
At C 100
At D 100
Explanation: The temperature will remain 0 degrees Celsius until all the ice becomes water and the temperature will remain 100 degrees Celsius until all the water changes into steam.
Pls help me solve these two questions!!! Tq
Answer:
Part A would be 80 Joules and Part B would be 20 meters.
Explanation:
For Part A:
The first step is to convert the mass to SI units.
400 g = 0.4 kg
Next, we need to know that the law of conservation of energy states that the total energy of an isolated system is conserved. In this case, it means that the total energy at the bottom, where kinetic energy is greatest, will be equal to the total energy at the top, where gravitational potential energy is greatest.
Max Gravitational Potential Energy = Max Kinetic Energy
Max Gravitational Potential Energy = [tex]\frac{1}{2} mv^{2}[/tex]
Max Gravitational Potential Energy = [tex](\frac{1}{2} )(.4kg)(20m/s)^2[/tex] = 80[tex]J[/tex]
For Part B:
We need to once again set gravitational potential energy to kinetic energy, only this time we use the GPE equation and solve for height. We already solved for the kinetic energy so we just plug everything in and solve.
[tex]mgh = \frac{1}{2} mv^{2}[/tex]
[tex](.4kg)(10m/s^{2} )h = 80J\\h = 20m[/tex]
A converging lens of focal length 20cm, forms a real image twice the size of the object. Calculate:
i) the power of the lens;
ii) the position of the image.
Answer:
Solition given:
focal length(f)=20cm
size of image(v)=2x
size of object(u)=x
we have
power of lens= reciprocal to focal length=1/20=0.05/cm
ii.
the position of the image is beyond C.
Explanation:
See the attachment !!!!!!!
If the ring rolls (without slipping) all the way to point 2, what is the ring's energy at point 2 in terms of h2 and v2?
Answer:
Following are the response to the given question:
Explanation:
[tex]F_2=mgh_2+\frac{1}{2}mv_2^2+\frac{1}{2}mR^2(W)^2\\\\\therefore \\\\ \to WR=v_2\\\\E_2=Mgh_2+MV_2^2[/tex]
3 write the three laws given by kepler.How did they help Newton to arrive at the inverse square law of gravity?
Answer:
Kepler's laws apply: First Law: Planetary orbits are elliptical with the sun at a focus. Second Law: The radius vector from the sun to a planet sweeps equal areas in equal times. Third Law: The ratio of the square of the period of revolution and the cube of the ellipse semimajor axis is the same for all planets.
Ignore friction. A 20. Lb. Object was lifted to a height of 10 feet by a force of 30. Lb. (a) How much work (ft.Lb) is done by the force? (b) Find the change in potential energy (ft.Lb) of the object
(a) The work done by force in lb-ft is 300 lb-ft.
(b) The change in potential energy of the object is 200 lb-ft.
Work done by forceThe work done by force in lb-ft is calculated as follows;
W = Fd
W = 30 x 10
W = 300 lb-ft
Change in potential energyThe change in potential energy of the object is calculated as follows;
ΔP.E = P.Ef - P.Ei
ΔP.E = 20 x 10 - 0 = 200 lb-ft
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calculate the mass 9f the earth, assuring that uts is sphere with radius 6.67×10^6m.
Answer:
6.86 × 10²⁴ kg
Explanation:
The mass of the earth m = density of earth, ρ × volume of earth, V
m = ρV
The density of the earth, ρ = 5515 kg/m³ and since the earth is a sphere, its volume is the volume of a sphere V = 4πr³/3 where r = radius of the earth = 6.67 × 10⁶ m
Since m = ρV
m = ρ4πr³/3
So, substituting the values of the variables into the equation for the mass of the earth, m, we have
m = 5515 kg/m³ × 4π(6.67 × 10⁶ m)³/3
m = 5515 kg/m³ × 4π × 296.741 × 10¹⁸ m³/3
m = 5515 kg/m³ × 1189.9639π × 10¹⁸ m³/3
m = 6546105.64378π × 10¹⁸ kg/3
m = 20565197.400122 × 10¹⁸ kg/3
m = 6855065.8 × 10¹⁸ kg
m = 6.8550658 × 10²⁴ kg
m ≅ 6.86 × 10²⁴ kg
Quả bóng 200g chuyển động với v 4m/s đập vào tường rồi bật ra ngược chiều với cùng tốc độ độ biến thiên động lượng của quả bóng là
How can we drop eggs the fewest amount of times without breaking it?
Answer:
drop in water
Explanation:
follow me m mm m
If the force on a spring is 2 N and it stretched 0.5 m, what is the spring constant?
O A. 2 N/m
OB. 0.2 N/m
OC. 0.4 N/m
OD. 4 N/m
answer is
0.4n/m10. Explain the principle of electric motor. Write its uses.
Explanation:
The principle of an electric motor is based on the current carrying conductor which produces magnetic field around it. A current carrying conductor is placed perpendicular to the magnetic field so that it experiences a force.
The largest electric motors are used for ship propulsion, pipeline compression and pumped-storage applications with ratings reaching 100 megawatts. Electric motors are found in industrial fans, blowers and pumps, machine tools, household appliances, power tools and disk drives.
Which of the elements below have seven electrons in their outermost energy levels? A.) Cr, Mn, and Fe B.) Br, I, and Ci C.) O, S, and Se D.) He, Ne, and Ar
Answer:
B
Explanation:
the Halogen families have 7 valence electrons
Enlight the contribution of science and technology for current pandemic of Corona virus??
The vaccine ofcourse. They helped in making the vaccine.
Resistivity of metallic wire
depends on *
It's length
It's shape
It's thickness
Nature of material
Answer:
nature of the material
hope this help you
why does apparent depth of different liquids vary
A 250–g piece of gold is at 19 °C. 5.192 kJ of energy is added to it by heat. The specific heat of gold is 129 J/(kg·°C). Calculate its final temperature.
We heat a 25–g sample of metal from 10 °C to 100 °C. 1.082 kJ of energy is added to it by heat. Calculate
the specific heat of the metal.
Answer:
A. DT is given by Q= MCs DT
m = mass of the substances
Cs= is it's specific heat capacity
Ck= Q
Mk ×DTk
=250 × 9 × 5
129
=Dt = 180.1085271
answer is 180degree C.
Explanation:
B. = 25×10 ×100
1.082
=2500
1.082
= 23105.360 g/kj.
The final temperature is 180 degree. and the specific heat of the metal is 23105.360 g/kj.
How to calculate the specific heat?Q = m . C . ΔT
Q = heat; m = mass; C is the specific heat and
ΔT = Final T° - Initial T°
Q = C lat . m
Q = Heat
m = mass
C lar = Latent heat of fusion
A) DT is given by Q= M Cs DT
where, m = mass of the substances
Cs= is it's specific heat capacity
Ck= Q
Mk × DTk
=250 × 9 × 5
129 =Dt = 180.1085271
Thus, the final temperature is 180 degree.
B) We heat a 25–g sample of metal from 10 °C to 100 °C. 1.082 kJ of energy is added to it by heat = 25×10 ×100
=2500
1.082
Q = 23105.360 g/kj
Hence, the specific heat of the metal is 23105.360 g/kj.
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why football players boots have spikes their sole
Give short and sweet answer
Answer:
it helps with balance and speed.
"The football shoes have spikes or studs because the studs or spikes provides larger frictional force than normal shoes while running on the grass. The studs prevents player from slipping on the grass and help to run faster and change direction quickly without slipping"
Answer:
they provide a larger frictional force than normal shoes while running on the grass.
Will mark brainlest helpp!!!!!!
Answer:
I don't know if it is correct or not.
Convert to m/s
[tex]\\ \Large\sf\longmapsto v=60\times \dfrac{5}{18}=16.6m/s[/tex]
Time=t=5min=5×60=300sWe know
[tex]\boxed{\Large{\sf Acceleration=\dfrac{v-u}{t}}}[/tex]
[tex]\\ \Large\sf\longmapsto Acceleration=\dfrac{16.6-0}{300}[/tex]
[tex]\\ \Large\sf\longmapsto Acceleration=\dfrac{16.6}{300}[/tex]
[tex]\\ \Large\sf\longmapsto Acceleration=0.05m/s^2[/tex]
Distance=sUsing second equation of kinematics
[tex]\boxed{\Large{\sf s=ut+\dfrac{1}{2}at^2}}[/tex]
[tex]\\ \Large\sf\longmapsto s=0(300)+\dfrac{1}{2}(0.05)(300)^2[/tex]
[tex]\\ \Large\sf\longmapsto s=0.05\times 150^2[/tex]
[tex]\\ \Large\sf\longmapsto s=0.05\times 22500[/tex]
[tex]\\ \Large\sf\longmapsto s=1125m[/tex]
Ра:
5. Mass of the earth is 6x10-kg and its radius is 6400km. What is the
mass of a man weighting 977N?
(99.99kg)
ma
Orth
be
Answer:
what do u need help with
Explanation:
Pа: 5. Mass of the earth is 6x10-kg and its radius is 6400km. What is the mass of a man weighting 977N? (99.99kg) ma. Orth be.
please answer fast..........
Answer:
The correct answer is a. Subsonic
Hope this helps you^_^
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Define derived unit with example
Answer:
A derived unit is a SI unit of measurement comprised of a combination of the seven base units. Like SI unit of force is the derived unit, newton or N where N=s21×m×kg. There are some commonly used derived units which includes: 1. Pressure = AreaForce=m2N.
Explanation:
what ia measurement in science?
= The process of comparing an unknown quantities with an standard known quantities is called measurement.
Yes it is the measurement in science
