Explanation:
In this chapter, we will study the important concepts of kinetic energy and the
closely related concept of work and power.
A- Kinetic Energy
Kinetic energy is a physical quantity, which is associated with the moving objects
and defined as:
K = ½ mv2
If the body is stationary (v=0), its kinetic energy is zero. The SI unit of kinetic
energy is kg.m2
/s2
or Joule (J), where 1 J=1 kg.m2
/s2
. Kinetic energy is a scalar
quantity.
B- Work
The work is defined as the ability to perform a force along a certain displacement.
There are different types of work as follows:
1- Work done by a constant force
The work done by the constant force F is given by the scalar product of the force F
and the displacement d.
WF = F.d = Fd cosθ
where θ is the angle between the force and displacement. The above equation means
that the work is the product of the displacement magnitude by component of the
force parallel to the displacement. Therefore, work is a scalar quantity (only
magnitude, no direction) and can be positive, negative, or zero. The SI unit of work
is (N.m) or joule (J) where 1 N.m = 1 J.
Special cases and remarks:
• If the angle between the force and displacement is zero (parallel), the work is
WF = F d (maximum work)
For the vertical part, W = (200 N) * (10 m) * cos (0 deg) = 2000 J. For the horizontal part, W = (50 N) * (35 m) * cos (0 deg) = 1750 J. The total work done is 3750 J (the sum of the two parts).
A 1.5 kg cart is attached to a spring with spring constant of 5 N/m. The cart & spring is pulled to stretch the spring by 3 meters.
What is the SPE?
22.5 J
Explanation:
Given:
x = 3 m
[tex]k = 5\:\text{N/m}[/tex]
The spring potential energy [tex]PE_s[/tex] is
[tex]PE_s = \frac{1}{2}kx^2 = \frac{1}{2}(5\:\text{N/m})(3\:\text{m})^2[/tex]
[tex]\:\:\:\:\:\:\:=22.5\:\text{J}[/tex]
An object with an initial velocity of 10 m/s accelerates at a rate of 3.5 m/s2 for 8 seconds. How far will it have traveled during that time?
Free-fall Acceleration is -10 m/s^2
I also need the formula
Answer:
Explanation:
s = s₀ + v₀t + ½at²
assuming that the acceleration is in the direction of initial velocity.
(it would not have to be so)
s = 0 + 10(8) + ½(3.5)(8²)
s = 192 m
A ball is thrown up into the air. When it gets to the very top,
what kind of energy does it have?
At the highest attitude, the velocity of the ball is 0 m/s, so the kinetic energy is 0 as well.
Hence the answer is potential energy because it doesn't depend on velocity .
What is the difference between the contagion theory and the convergence
theory?
O A. One deals with how people behave before a riot, and the other
deals with how people behave after a riot.
O B. One deals with adults with no power, and the other deals with
authority figures.
O C. One deals with how people are affected by a crowd, and the other
deals with how people actively drive a crowd's Behavior.
O D. One deals with people from democratic governments, and the
other deals with people from authoritarian governments.
Answer: Contagion theory states that crowds cause people to act in a certain way; convergence theory says the opposite, claiming that people who wish to act in a certain way come together to form crowds.
Explanation: Its C
The equation for a progressive wave is y=6 cos(20t-4x) What is the equation of another progressive wave which has twice the amplitude and frequency, and moving in the same direction?
The equation of the progressive wave is y = 12 cos(40t - 4x)
The general wave equation is given by:
y = A sin(ωt - kx)
Where A is the amplitude, ω is the angular frequency = 2πf, f is the frequency, k is the wave number and y, x is the displacement.
Given the equation for a progressive wave is y=6 cos(20t-4x). Hence:
The amplitude A = 6,
ω = 20 = 2πf
f = 20/2π = 3.183 Hz
Twice the amplitude = 2 * 6 = 12, twice the frequency = 2 * 3.183.
ω = 2π(3.183*2) = 40
Therefore the other progressive wave has an equation of:
y = 12 cos(40t - 4x)
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5) You pull a 10.0 kg wagon along a flat road. You exert a force of 80.0 N at an angle of 30.0 degrees above the horizontal while you move the wagon 10.0 m forward. The coefficient of friction between the wagon and road is 0.500. Calculate the work down by you and the work done by friction.
Can someone solve by showing the steps?
This question involves the concepts of work done and the frictional force.
a. Work done by the person is "692.82 N".
b. Work done by the frictional force is "490.5 N".
a.
Work done by the person can be given by the following formula:
[tex]W=FdCos\theta[/tex]
where,
W = work done by the person = ?
F = Force applied by the person = 80 N
d = distance traveled = 10 m
θ = angle between force and motion = 30°
Therefore,
[tex]W=(80\ N)(10\ m)Cos30^o[/tex]
W = 692.82 N
b.
Work done by the frictional force is given by the following formula:
[tex]W_f=fd\\W_f=\mu mgd[/tex]
where,
[tex]W_f[/tex] = work done by the frictional force = ?
μ = coefficient of friction = 0.5
g = acceleration due to gravity = 9.81 m/s²
Therefore,
[tex]W_f=(0.5)(10\ kg)(9.81\ m/s^2)(10\ m)[/tex]
[tex]W_f=490.5\ N[/tex]
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Find the self-inductance of a 1700-turn solenoid 55 cm long and 4.0 cm in diameter. Express your answer with the appropriate units.
The self-inductance of the solenoid is 8.25 mH.
The given parameters;
number of turns, N = 1700 turnlength of the solenoid, l = 55 cm = 0.55 mdiameter of solenoid, d = 4 cmradius of the solenoid, r = 2 cm = 0.02 mThe area of the solenoid is calculated as follows;
[tex]A = \pi r^2\\\\A = \pi \times (0.02)^2\\\\A = 0.00125 \ m^2[/tex]
The self-inductance of the solenoid is calculated as follows;
[tex]L = \frac{\mu_o N^2 A }{l} \\\\L = \frac{(4\pi \times 10^{-7}) \times 1700^2 \times 0.00125}{0.55} \\\\L = 0.00825 \ H\\\\L = 8.25\ mH[/tex]
Thus, the self-inductance of the solenoid is 8.25 mH.
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Jack sits in the chair of a Ferris wheel that is rotating at a constant 0.150 rev/srev/s . As Jack passes through the highest point of his circular part, the upward force that the chair exerts on him is equal to one-fourth of his weight.
What is the radius of the circle in which Jack travels? Treat him as a point mass.
Answer:
Explanation:
At the top of the arc, 3/4 of the acceleration of gravity is use to supply the necessary centripetal acceleration.
0.75g = ω²R
R = 0.75g/ω²
R = 0.75(9.81) / (0.15 rev/s)(2π rad/rev)²
R = 8.283006...
R = 8.28 m
Question 3. A wire 25.0cm long lies along the z-axis and carries a current of 9.00A in the +z-direction. The a magnetic field is uniform and has components Bx = -0.242T, By= -0.985, and B2=-0.336. a. Find the components of the magnetic force on the wire? b. What is the magnitude of the net magnetic force on the wire?
a.
The components of the force are Fx = 2.2163 N, Fy = -0.5445 N and Fz = 0 N
The force on a current carrying conductor in a magnetic field is given by F = iL × B where i = current = 9.00 A, L = 25.0 cmk = 0.25 mk (since the conductor is along the z-direction). B = magnetic field. Since B has component Bx = -0.242T, By= -0.985, and Bz = -0.336, B = -0.242i + (-0.985j) + (-0.336)k = -0.242i - 0.985j - 0.336)k.
So, F = iL × B
F = 9.00 A{(0.25 m)k × [-0.242Ti + (-0.985Tj) + (-0.336T)k]T}
F = 9.00 A{(0.25 m)k × (-0.242T)i + (0.25 m)k × (-0.985Tj) + (0.25 m)k × (-0.336T)k]}
F = 9.00 A{-0.0605mT)k × i + (-0.24625 mT)k × j + (-0.084 m)k × k]}
F = 9.00 A{-0.0605mT)j + (-0.24625 mT) × -i + (-0.084 mT) × 0]}
F = 9.00 A{-0.0605mT)j + (0.24625 mT)i + 0 mT]}
F = -0.5445 AmT)j + (2.21625 AmT)i + 0 AmT]}
F = -0.5445j + 2.21625i + 0 k
F = (2.2163i - 0.5445j + 0 k) N
So, the components of the force are Fx = 2.2163 N, Fy = -0.5445 N and Fz = 0 N
b.
The magnitude of the net force on the wire is 2.282 N
The net force F = √(Fx² + Fy² + Fz²)
F = √[(2.2163 N)² + (-0.5445 N)² + (0 N)²)
F = √[(4.912 N)² + 0.2964 N)² + (0 N)²)
F = √[5.2084 N)²
F = 2.2822 N
F ≅ 2.282 N
So, the magnitude of the net force on the wire is 2.282 N
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. A load of 250 kg is hung by a crane’s cable. The load is pulled by a horizontal force such that the cable makes a 300 angle to the vertical plane. If the load is in the equilibrium, calculate the magnitude of the tension in the cable.
If the load is in the equilibrium, the magnitude of the tension in the cable is equal to 1,414.5 Newton.
Given the following data:
Mass of load = 250 kgAngle of inclination = 30°Scientific data:
Acceleration due to gravity = 9.8 [tex]m/s^2[/tex]To calculate the magnitude of the tension in the cable, if the load is in the equilibrium:
First of all, we would determine the tension caused by the horizontal component of the force:
[tex]\sum F_y ; Tcos\theta - mg=0\\\\Tcos\theta = mg\\\\T=\frac{mg}{cos\theta} \\\\T=\frac{250 \times 9.8}{cos30} \\\\T= \frac{2450}{0.8660}[/tex]
T = 2,829.1 Newton
The magnitude of the tension in the cable is given by:
[tex]\sum F_x ; F - Tsin\theta = 0\\\\F = Tsin\theta\\\\F = 2829.1sin30\\\\F = 2829.1 \times 0.5[/tex]
F = 1,414.5 Newton.
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calculate the speed of longitudinal waves in aluminum (assuming the elastic modulus = 6.89 x 10^4 MPa)
The expression for the speed of waves in materials allows us to find the result for the speed of sound in aluminum is:
Sound speed is: v = 5050 m / s
The speed of a wave in a material is determined by the relationship between its volumetric modulus and its density, it is given by the expression.
v = [tex]\sqrt{ \frac{B}{\rho} }[/tex]
where v is the speed of the wave in the material (sound), B is the volume modulus and ρ the density.
They indicate that the volumetric or elastic modulus of aluminum is;
B = 6.89 10⁴ Mpa ( [tex]\frac{10^6 \ Pa}{1 \ MPa}[/tex] ) = 6.89 10¹⁰ Pa
The density of aluminum is tabulated ρ = 2.7 10³ kg / m³
We calculate.
v = [tex]\sqrt{ \frac{6.89 \ 10^{10} }{2.7 \ 10^3 }}[/tex]
v = 5.05 10³ m / s
In conclusion using the expression for the speed of waves in materials we can find the result for the speed of sound in aluminum is:
v = 5050 m / s
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A 400 g ball swings in a vertical circle at the end of
a 1.5-m-long string. When the ball is at the bottom
of the circle, the tension in the string is 10 N.
A) what is the speed of the ball at that point?
Answer:
a = 25 m/s2
Explanation:
A = f/m
A = Speed/Acceleration
F =‘Force
M = Mass
The elevation at the base of a ski hill is 350 m above sea level. A ski lift raises a skier (total mass=72 kg, including equipment) to the top of the hill. If the skier's gravitational potential energy relative to the base of the hill is now 9.2 x 105 J, what is the elevation at the top of the hill?
The elevation at the top of the hill is 1,653.85 m.
The given parameters;
initial height of the skier, h₁ = 350 mlet the final height of the skier at the hill top, = h₂total mass, m = 72 kggravitational potential energy of the skier, P.E = 9.2 x 10⁵ JThe elevation at the top of the hill is calculated as follows;
[tex]P.E = mg\Delta h\\\\P.E = mg(h_2 -h_1)\\\\h_2 -h_1 = \frac{P.E}{mg} \\\\h_2 = \frac{P.E}{mg} + h_1\\\\h_2 = \frac{9.2 \times 10^5 }{72 \times 9.8} \ + \ 350 \ m\\\\h_2 = 1,653.85 \ m[/tex]
Thus, the elevation at the top of the hill is 1,653.85 m.
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Use a trigonometric equation to
determine the leg of this triangle.
10 m
[?]
m
30°
Answer:
5m
Explanation:
x=?
[tex]sin30^{0} =\frac{x}{10}[/tex]
[tex]x=10sin30^{0} =10(0.5)=5[/tex]
Hope this helps
Why metals have thermoconductivity higher than ceramic?
Answer:
Thermal Conductivity Easily Transmits Heat Among Fine Ceramics
A wheel has a radius of 0.40 m and is mounted on frictionless bearings. A block is suspended from a rope that is wound on the wheel and attached to it (see figure). The wheel is released from rest and the block descends 1.5 m in 2.00 s without any slipping of the rope. The tension in the rope during the descent of the block is 20 N. What is the moment of inertia of the wheel?
Hi there!
We can begin by calculating the acceleration of the block and the wheel using the following equation:
d = vit + 1/2at², where initial velocity = 0 m/s
d = 1/2at²
2d/t² = a
2(1.5)/2² = 0.75 m/s²
Now, we can do a summation of torques:
∑τ = rT
Rewrite using Newton's 2nd Law for rotation:
Iα = rT
Convert α to a using the relationship α = a/r:
I(a/r) = rT
Ia = r²T
I = r²T/a
Plug in the values:
I = (0.40²)(20)/(0.75) = 4.267 kgm²
Tendency of matter to change in shape, area, volume in response to a change in particular temperature is called
Why Amphibians are Vanishing
Answer:Climate change, emerging diseases, and increased exposure to ultraviolet radiation (due to ozone depletion) are all additional factors that could be contributing to falling amphibian populations. ... Instead, amphibians are disappearing thanks to a complex mixture of factors, including: Alien Specie
Explanation:
just look it up........
PLEASE HELP!
A 2457 kg car moves with initial speed of 18 ms-?. It is stopped in 62 m by its brakes.
How much work is done by the brakes?
Answer:
Explanation:
The work of the brakes will equal the initial kinetic energy of the car
Fd = ½mv²
F = mv²/2d
F = 2457(18²) / (2(62))
F = 6,419.903...
F = 6.4 kN
A flywheel having constant angular acceleration requires 4.70 s to rotate through 164 rad . Its angular velocity at the end of this time is 101 rad/s . Find the angular velocity at the beginning of the 4.70 s interval. Find the angular acceleration of the flywheel.
Answer:
A) -31.2 rad/s
B) 28.1 rad/s^2
Explanation:
A car starts from rest and accelerates uniformly over a time of 5.21 seconds for a distance of 110 m. Determine the acceleration of the car.
Answer:
The acceleration of the car is 8.10 m/s²
Explanation:
Given:d = 110 m
t = 5.21 s
vi = 0 m/s
To Find:a = ?
d = Vᵢ × t + 0.5 × a × t²
110 m = (0 m/s) × (5.21 s) + 0.5 × (a) × (5.21 s)²
110 m = (13.57 s²) × a
a = (110 m)/(13.57 s²)
a = 8.10 m/s²
Thus, The acceleration of the car is 8.10 m/s²
-TheUnknownScientist 72
A rock is thrown off a cliff with a speed of 5 m/s downward. How far will it fall after 7 seconds have elapsed?
Free-fall Acceleration is -10 m/s^2
I also need the Formula
Answer:
Explanation:
s = s₀ + v₀t + ½at²
if the throw point is origin and UP the positive direction and ignoring air resistance.
s = 0 + (-5)(7) + ½(-10)(7²)
s = 0 - 35 - 245
s = - 280 m
A circular coil having 60 turns has a radius of 75 mm. What current must exist in the coil
to produce a magnetic field of 300 μT at the center of the coil?
Answer:
Explanation:
Step 1 of 4
CONCEPT:
The mathematical expression for magnetic field B at center of a coil:
Here, is the current in the coil, N is the number of turns of the coil, is the permeability of the free space and is radius of the coil.
Rearrange above equation for current in the coil.
F (N)
4
* 0
3
A
2
FIGURE 2
t(s)
5
0
1
2
3
4
3) A force of magnitude Fx acting in the x-direction on a 2.00 kg particle varies in time as shown
in FIGURE 2. Find
a) The impulse of the force
b) The final velocity of the particle if it is initially at rest
c) The final velocity of the particle if it is initially moving along the x-axis with velocity
of -2.00 ms -1
Answer:
Mark me as brainlist please.
is a fuel cell a primary or secondary cell
Answer:
Enrol in our 50 studyscore masterclass. Click here! Fuel cells are a type of primary cell in that they are not recharged, However, they are unique because they never run out, if the reactants are constantly supplied.
please paraphrase this paragraph
As a conclusion we first learned what is Discrete Fourier Transform and
why is it very important in signal processing science as it helps us to convert the discrete signal from time domain into frequency domain and the inverse DFT does the opposite converting the signal from frequency domain back into time domain. We have also learned the difference between DFT and the FFT algorithm where the FFT is an efficient
algorithm created to simplify the DFT process as it is faster and more accurate. We also learned how to perform and implement this algorithm using Matlab,
Answer:
The importance of signal processing science as has been made clear. Since we now know that it help to convert discrete signal from time domain to frequency domain. Moreover, we are now aware of the difference in DF5 and FFT algorithms as well as the implementation in Matlab.
What is the best description of the distribution of the galaxies that lie within about 200 Mpc of Earth
if the Periodic time of an oscillating object Triples then its frequency will?
Answer:
it would decrease
Explanation:
f=1/T
Objects 1 and 2 attract each other with a gravitational force of 179 units. If the distance separating objects 1 and 2 is changed to four times the original value (i.e., quadrupled), then the new gravitational force will be ______ units.
Explanation:
Fgravity = G*(mass1*mass2)/D²
G is the gravitational constant throughout the universe.
D is the distance between the 2 objects.
the distance is now quadrupled.
Fgravitynew = G*(mass1*mass2)/(4D)² =
= G*(mass1*mass2)/(16D²) =
= (G*(mass1*mass2)/D²) / 16 = Fgravity/16
the new gravitational force will be 179/16 = 11.1875 units
You spit a wad of paper horizontally
from a height of 1.8 m. The wad
leaves your mouth with a velocity of
6 m/s. How long does it take the
wad to hit the ground?