Answer:
(a) 15 N
(b) 39.2 N
(c) The coefficient of sliding friction is 2.61[tex]\bar 3[/tex]
Explanation:
The given parameters are;
The mass of the brick = 4.0 kg
The nature of the surface on which the brick rests = Horizontal
The force needed to move the brick from rest = 15 N
(a) Given that the body is not accelerating, the force applied = The frictional force = 15 N
Which can also be expressed as follows;
The magnitude of the frictional force = The force needed to push the brick to move from rest and move with a constant velocity = 15 N
(b) The magnitude of the normal force = The force acting at right angles to the surface opposite in direction and equal in magnitude to the weight of the brick, so as hold the brick and prevent it from passing through the surface. which is given as follows;
The weight of the block = The magnitude of the normal force =The mass × The acceleration due to gravity = 4.0 × 9.8 = 39.2 N
The magnitude of the normal force = 39.2 N
(c) The frictional force, F = [tex]\mu _k[/tex] × Normal force
Where;
[tex]\mu _k[/tex] = The coefficient sliding friction
By substituting the known values gives
15 = μ × 39.2
[tex]\mu _k[/tex] = 15/39.2 = 2.61[tex]\bar 3[/tex].
which of these properties is the best measure of a star's brightness?(1 point) absolute magnitude absolute magnitude age age size size apparent magnitude
Apparent magnitude refers to the properties which best measures a star's brightness and is denoted as option D.
What is Apparent magnitude?This is a term commonly used in astronomical system which talks about the brightness of a star based on its composition such as hydrogen and helium.
it is also determined by how far or bright it is from the planet such as earth when they are viewed by individuals which is regarded as the property in which astronomers use to define its brightness.
This is therefore the reason why apparent magnitude was chosen as the correct choice.
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Answer:
A: Absolute magnitude
Explanation:
I Just did it and the correct answer is ABSOLUTE MAGNITUDE
Why does surface water disperse when touched with soap?
The end of the detergent molecule which attaches to fat (grease) repels water molecules. It is known as hydrophobic, meaning "water fearing." By attempting to move away from the water molecules, the hydrophobic ends of the detergent molecules push up to the surface. This weakens the hydrogen bonds holding the water molecules together at the surface. The result is a break in the surface tension of the water.
Answer:
In a soap-and-water solution the hydrophobic (greasy) ends of the soap molecule do not want to be in the liquid at all. Those that find their way to the surface squeeze their way between the surface water molecules, pushing their hydrophobic ends out of the water. This separates the water molecules from each other.
Explanation:
what is work please give ans
Marcus is hanging a porch swing on his front porch. The first thing he has to do is attach two springs to the ceiling. Then, he fastens the swing to the springs so that they can stretch and support the weight of the swing. Which two types of potential energy do the springs have?
Answer:
Gravitational potential energy and Elastic potential energy
Explanation:
The two types of potential energy the springs described in the question have are Gravitational potential energy and Elastic potential energy.
Firstly, it must be noted that potential energy is the energy stored/present in a stationary (non-moving) object (or object at rest).
Gravitational potential energy is the potential energy as a result of the vertical position of an object due to force of gravity acting to pull it down. The gravitational potential energy is as a result of the springs been attached to the ceiling which causes the force of gravity to want to pull it down. This gravitational force is further increased when the swing is attached causing the weight of swing to act in the direction of the force of gravity.
Elastic potential energy is the potential energy stored in an elastic object or energy stored in an object that can be stretched or compressed. This is the energy that would always be found in a spring, so when the springs have been attached to the ceiling and the swing has been fastened to them, there elastic potential energy would reduce as a result of the kinetic energy that must have been used to stretch the springs.
1. Which is one characteristic of a SMART fitness goal?
A. Endurance
B. Intensity
C. Attainable
D. Believable
Answer:
I would say D. Believable. Sorry if its wrong.
Explanation:
Force is measured in what unit? What is this unit equal to in other units?
Force is measured in Newton ( kg.m. /s²)
Please help! Didn’t have right subject so i chose one that may be similar.
Tides are caused by
the rotation of the Earth
the orbit of the Moon
gravitational pull of just the Sun
gravitational pull of the Sun and Moon
Answer:
Moon's Orbit
Explanation:
Answer:
saaaaaaaaaaaay it please
Explanation:
C: Calculate the kinetic energy of a car with a mass of 1563 kilograms that is traveling at 42 kilometers per hour.
HELP PLEASEE
Hello!
C. KE ≈ 9120.105 J
D. m = 151.45 kg
Question C:
Calculate kinetic energy using the formula:
[tex]KE = \frac{1}{2}mv^{2}[/tex]
Substitute in the given mass. We have to convert kilometers to meters in order to solve.
[tex]\frac{42km}{1hr} * \frac{1hr}{3600sec} *\frac{1000m}{1km} = 11.67 m/s[/tex]
Use the equation above:
KE = 1/2(1563)(11.67)
KE ≈ 9120.105 J
Question D:
Plug in the given Kinetic Energy and velocity to solve. Convert kilometers/hour to meters/second:
[tex]\frac{7km}{1hr} * \frac{1hr}{3600sec} *\frac{1000m}{1km} = 1.94 m/s[/tex]
[tex]KE = \frac{1}{2}mv^{2}[/tex]
285 = 1/2(m)(1.94²)
570 = (1.94²)m
151.45kg = m
Question 24 (2 points)
What is power? (2 points)
O a
O b
O c
Od
The magnitude of a force needed to move an object
How much work can be done in a given time
The distance over time that an object moves
The energy needed to create work
All battery powered devices, run off of what type of power?
Answer:
Electrical energy
Explanation:
electrical energy Essentials. A battery is a device that stores chemical energy and converts it to electrical energy. The chemical reactions in a battery involve the flow of electrons from one material (electrode) to another, through an external circuit. The flow of electrons provides an electric current that can be used to do work.
A 33 kg box sits at rest on a tabletop.
Draw and clearly label all the forces acting on the box;
Calculate the normal force.
Answer:
323.4N
Explanation:
Given parameters:
Mass of the box = 33kg
Unknown:
Normal force on the body = ?
Solution:
The normal force of a body is the vertical force the body exerts on another body.
It is expressed as;
Normal force = mass x acceleration due to gravity
Acceleration due to gravity = 9.8m/s²
Normal force = 33 x 9.8 = 323.4N
The movie "The Gods Must Be Crazy" begins with a pilot dropping a bottle out of an airplane. A surprised native below, who thinks it is a message from the gods, recovers it. If the plane from which the bottle was dropped was flying at a height of 500 m, and the bottle lands 400 m horizontally from the initial dropping point, how fast was the plane flying when the bottle was released? Draw a 2-dimensional motion map for the velocities and another for the acceleration.
Answer:
1) The Speed of the plane is approximately 39.596 m/s
2) Please find attached the required velocity and acceleration graphs
Explanation:
1) The height at which the plane was flying, h = 500 m
The location the bottle lands from the initial dropping point = 400 m
The time it takes the bottle to land is given by the equation for free fall as follows;
h = 1/2·g·t²
Where;
g = The acceleration due to gravity = 9.8 m/s²
t = √(h/(1/2·g) = √(500/(1/2×9.8) ≈ 10.102
The Speed of the plane = The horizontal velocity of the bottle = 400/10.102 ≈ 39.596
The Speed of the plane ≈ 39.596 m/s
2) Please find attached the velocity graph for the vertical and horizontal velocities of the bottle and the acceleration graph for the vertical motion of the bottle, created with Microsoft Excel
what is gravity ?short ans
Answer:
Gravity, or gravitation, is a natural phenomenon by which all things with mass or energy—including planets, stars, galaxies, and even light—are brought toward one another. On Earth, gravity gives weight to physical objects, and the Moon's gravity causes the ocean tides.
Mendeleev recognized the periodic law. True or False
Answer: True
Explanation:
How much work is needed to move an object 20 meters with 40 newtons of force?
a) 800 J
b) 850 N
c) 875 W
d) 825 m
Answer:
a) 800 J
Explanation:
Work is said to be done when a force induces movement over a distance in an object. The amount of work done (W) is calculated by multiplying the force by the distance traveled.
That is;
W = F × d
Where;
W = work done (J or N/m)
F = force (N)
d = distance (m)
In the information given in this question, F = 40N, d = 20m
Hence,
Work done = 40N × 20m
Work done = 800N/m or 800 J
A missile is moving 1350 m/s at a 25.0° angle. It needs to hit a target 23,500 m away in a 55.0° direction in 10.20 s. What is the direction of its final velocity? Answer in direction (deg)
Answer:
(3504 m/s, 66°)
The final velocity of the missile is approximately 3504 m/s at an angle of 66 degrees.
Explanation:
We are going to use the horizontal and vertical components of this object since it is in projectile motion.
We are given the initial velocity of the missile; 1350 m/s at an angle of 25 degrees. We are also given the displacement in the x-direction: 23,500 meters at an angle of 55 degrees. The total time of this projectile in motion is 10.20 seconds.
Using this information, we can break up the motion of the projectile into its horizontal and vertical components and solve for the unknown variables [tex]a[/tex] and [tex]v_f[/tex].
Horizontal direction (x):List out the known variables:
[tex]v_i=1350[/tex] [tex]v_f=?[/tex] [tex]\triangle x=23500[/tex] [tex]a=?[/tex] [tex]t=10.20[/tex]Since we have initial velocity, displacement, and time, we can use one of the kinematic equations for constant acceleration that contains these variables, including acceleration, and solve for a:
[tex]\triangle x=v_it + \frac{1}{2}at^2[/tex]We are solving for acceleration in the x-direction, so this equation should be in terms of the x-direction:
[tex]\triangle x_x=(v_i)_x t +\frac{1}{2}a_x t^2[/tex]Let's break up the displacement into its horizontal (x) component:
[tex]23500cos(55)[/tex]Let's break up the initial velocity into its horizontal component:
[tex]1350cos(25)[/tex]Plug these values into the equation and 10.20 seconds for t.
[tex]23500cos(55)=1350cos(25) \cdot t + \frac{1}{2}a_x (10.20)^2[/tex]Solve for [tex]a_x[/tex].
[tex]23500cos(55)=12479.85823+52.02a_x[/tex] [tex]999.1880243=52.02a_x[/tex] [tex]a_x=19.20776671[/tex]The acceleration in the x-direction is about 19.21 m/s².
Now, we can use this acceleration and solve for the final velocity in the x-direction using this constant acceleration kinematic equation:
[tex]v_f=v_i+at[/tex]Use this equation in terms of the x-direction:
[tex](v_f)_x=(v_i)_x+a_xt[/tex]Plug the known values into the equation and solve for [tex](v_f)_x[/tex].
[tex](v_f)_x=1350cos(55)+19.20776671 \cdot 10.20[/tex] [tex](v_f)_x=1419.434733[/tex]The final velocity in the x-direction is about 1419.43 m/s.
Vertical direction (y):This process will be the same as solving for acceleration and final velocity in the x-direction, except this time we will be using the vertical (y) components.
[tex]\triangle x_y=(v_i)_y t +\frac{1}{2}a_y t^2[/tex]Vertical component of initial velocity:
[tex]1350sin(25)[/tex]Vertical component of displacement:
[tex]23500sin(55)[/tex]Plug known values into the equation and solve for [tex]a_y[/tex].
[tex]23500sin(55)=1350sin(25) \cdot (10.20) + \frac{1}{2}a_y (10.20)^2[/tex] [tex]23500sin(55)=5819.453464 +52.02a_y[/tex] [tex]13430.61958=52.02a_y[/tex] [tex]a_y=258.181845[/tex]The acceleration in the y-direction is about 258.18 m/s².
Now let's use the same equation we used previously to solve for the final velocity in the y-direction.
[tex]v_f=v_i+at[/tex]Use this equation in terms of the y-direction:
[tex](v_f)_y=(v_i)_y+a_y t[/tex]Plug known values into the equation and solve for [tex](v_f)_y[/tex].
[tex](v_f)_y=1350sin(25)+258.181845 \cdot 10.20[/tex] [tex](v_f)_y=3203.989472[/tex]The final velocity in the y-direction is about 3203.99 m/s.
Final velocity and direction:The magnitude of the final velocity is the square root of the final velocity in the horizontal and vertical directions squared and added together.
[tex]|v|=\sqrt{(v_f)^2_x + (v_f)^2_y}[/tex]Plug the final velocity in the x and y-directions into the equation.
[tex]|v|=\sqrt{(1419.434733)^2+(3203.989472)^2}[/tex] [tex]|v|=\sqrt{2014794.961+10265548.54}[/tex] [tex]|v|=\sqrt{12280343.5}[/tex] [tex]|v|=3504.332105[/tex]The magnitude of the final velocity is about 3504 m/s. We can solve for the direction of the final velocity by using arccos to find the angle that is formed with the x-axis.
[tex]\displaystyle\theta = cos^-^1 \big{(} \frac{v_x}{|v|}\big{)} }[/tex]Plug in the x-component of the initial velocity and the magnitude of the final velocity of the projectile into the equation.
[tex]\displaystyle \theta =cos^-^1 \big{(}\frac{1419.434733}{3504.332105}\big{)}}[/tex] [tex]\displaystyle \theta = cos^-^1 \big{(} .4050514308 \big{)}}[/tex] [tex]\displaystyle \theta = 66.1056499[/tex]The direction of the final velocity is about 66 degrees.
can light cause plastic to melt? If yes does it matter what kind of light?
Answer:
plastics are susceptible to degradation due to ultraviolet (UV) light from the sun. With enough exposure, UV light can cause a chemical reaction in the plastic, which results in scission, or severing, of those big polymer molecules.
Explanation:
Answer:
the short answer is yes and sun or strong uv lights
Explanation:
LEDs cannot melt plastic fixtures as they just do not get that hot, not even at the base These new bulbs are based on field-induced polymer electroluminescent (FIPEL) technology, with a twist. Without heat as a continual stressor, the polymer should remain stable for years. Any kind of light bulbs, from fluorescent to incandescent to halogen, can cause fires if they are not used correctly. As more heat is put into the plastic, more bonds are broken and the material becomes more like a liquid and less like a solid. Semi-crystalline polymers have a melting temperature which is the point at which the secondary bonds in the crystalline regions break. At this point the mateiral is completely liquid. There is melt and there is soften. Certainly they soften and become weak in sunlight both by the heat and by the UV degredation of the plastic. Unfortunately, the plastics used for garbage bags have a low melting point but by design, they should not melt in strong sunlight. the underlined sentences are the most important
hello help me pls! i need serious help
Answer:c
Explanation:
Phase conductors 6 awg and smaller ____ permitted to be re-identified as equipment ground conductors using green paint, tape, or other effective means
Phase conductors 6 awg and smaller are not permitted to be re-identified as equipment ground conductors using green paint, tape, or other effective means.
Depending on the type of system offered, the grounded conductor of a service is typically a neutral conductor, though it can also be a phase conductor. A grounded phase conductor and no grounded neutral conductor are present in a corner-grounded delta system, for instance. The unbalanced load is returned to the source by the neutral. The conductor that has been purposefully grounded is the grounded conductor. The neutral is the conductor that is purposefully grounded in the majority of wiring systems used in industrial facilities, businesses, and homes. For safety reasons, the grounding conductor is employed. The grounding wire does not carry current under typical circumstances. The grounding wire offers a low resistance channel for the current in a fault situation.
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Calculate the wavelength of an orange light wave with a frequency of 5.085 x 10^14 Hz. The speed of light is 3.0 x 10^8 m/s.
^ meaning a power
Answer:
5.9 x 10⁻⁷m
Explanation:
Given parameters:
Frequency = 5.085 x 10¹⁴Hz
Speed of light = 3.0 x 10⁸m/s
Unknown:
Wavelength of the orange light = ?
Solution:
The wavelength can be derived using the expression below;
wavelength = [tex]\frac{v}{f}[/tex]
v is the speed of light
f is the frequency
wavelength = [tex]\frac{3 x 10^{8} }{5.085 x 10^{14} }[/tex] = 5.9 x 10⁻⁷m
A man applies a force of 500 N to push a truck 10 m down the street. How much work has been done? Please answer!
Answer:
5000 J
Explanation:
W=F*D
W=500N*10m
w=5000 J
When a man applies a force of 500 N to push a truck 10 m down the street. Then the work of 5000 J has been done.
What is Work ?Work done is the amount energy gained (loosed) in bringing the body from initial position to final position. It is denoted by W and its SI unit is joule(J). i.e. Work(W) is force(F) times displacement(s). W=F× s When a body is displaced with 1 newton of force by 1 m, then we can say that work has been done on the body by 1 joule.
Writing for it's dimension, W=F× s
Force has dimension [L¹ M¹ T²]
Displacement has dimension [L¹]
multiplying both the dimensions Force and Displacement we get, dimension of Work [L² M¹ T²].
Given,
F = 500 N
s = 10 m
Work = Fs = 500×10 = 5000 J
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A rectangular tank is filled with water to a depth of 4m. Calculate the pressure at the bottom of the tank. PLEASEEE HELP!! IM BEGGING!!!! PLEASEEEEE
For this we have the hidrostatic equation:
[tex]\boxed{P = \rho gh}[/tex]
Being:
P = Pressure
ρ = Density of liquid (water) = 1000 kg/m
g = Gravity = 9,81 m/s²
h = Height = 4 m
Replacing acording formula:
[tex]\boxed{P = 1000 \ kg/m ^{3} * 9,81 \ m/s^{2} * 4 \ m}[/tex]
Resolving:
[tex]\boxed{P = 39240 \ Pa}[/tex]
Result:
The pression at the bottom is 39240 Pa.
Consider these pictures in answering the question below.
с
D
Which diagram might represent the initial vertical component of the velocity of a ball thrown upward at an angle?
a
Ob
CU O
c
Od
Оe
E
Answer:
the answer would be D because not only is it going up but it's going up as an angle
At what seed is Jay traveling at 5 minutes into walk? At what time in his walk does he have the greatest speed?
The velocity of Jay after five minutes is 1 Km/min. The greatest speed occurred at 45 mins.
What is the velocity time graph?The velocity time graph is a representation of the movement of a body a body from one point to another. It is the plot of the velocity on the vertical axis against the time on the horizontal axis. Ideally this graph would be divided into three portions;
The region of uniform accelerationThe region of constant velocity The region of uniform decelerationWe can be able to read off from the graph, the instantaneous velocity of the object at any time. This could be done by tracing the time against the velocity axis and extrapolating according from the graph as shown.
Recall that the acceleration of the body is obtained as the slope of the velocity time graph at any point and the acceleration could be uniform or non uniform as judged from the velocity time graph.
Having said all these, it is clear that the velocity of Jay after five minutes is 1 Km/min.
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24. A soccer ball is kicked straight up into the air with a velocity of 10 m/s. How much time does it take the ball to reach its maximum height? (g = 10 m/s^2)
A 2 sec
B 100 sec
C 1.4 sec
D 1 sec
Answer:
D. Time t = 1 [s]
Explanation:
To solve this problem we must use the following equation of kinematics.
[tex]v_{f}=v_{o}-g*t[/tex]
where:
Vf = final velocity = 0 (when the ball reaches the maximum height its elevation won't be increased since the velocity is zero)
vi = initial velocity = 10 [m/s]
g = gravity acceleration = 10 [m/s²]
t = time [s]
Now replacing:
[tex]0 = 10-10*t\\10 = 10*t\\t = 1 [s][/tex]
A ship has a constant velocity of 8.33 m/sec. How far does it travel in done day?
Distanced travelled by a ship with a constant velocity in a day is 719712m
VELOCITY is defined as rate of change of displacement in a given interval of time.
it is a vector quantity.
its unit is m/s
to calculate the distance of a ship travelled
distance = speed x time
d = s x t ----1.
velocity of ship = 8.33m/s
time taken = 1 day =86400 sec
now using the above values in equation 1 we get
d =8.33m/s x 86400 sec
d = 719712m
thus a ship travels 719712m in a day.
Distanced travelled by a ship with a constant velocity in a day is 719712m
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courtney dauwalter leaves her home at 7 a.m. and takes his usual path to the top of mount elbert, arriving at 7 p.m. the following morning, she starts at 7 a.m. at the top of mount elbert and takes the same path back, arriving at her home at 7 p.m. determine if there exists a point on the path the courtney will cross at exactly the same time of day on both days. justify your answer.
There exists a point on the path the Courtney will cross at exactly the same time of day on both days.
Given that Courtney first takes his usual path and travel between 7.a.m. and 7.p.m.
Next morning, she travel backs between the time 7 a.m. and 7 p.m.
The time taken by Courtney on each day = 12 hours
12/2 = 6 hours.
6 hours from 7 a.m. is 1 pm. So this 6 hours will divide the total journey into two equal parts.
At 1 p.m. on first day, she will be in the middle of her way from home to Mount Elbert.
At 1.p.m. of the second day also, she will be in the middle of her way from Mount Elbert to her home.
So she cross the exact middle point of the path at exactly 1.pm on both days.
Intermediate Value theorem states this result. Since the distance travelled is a continuous function, there is a particular value of time corresponding to the exact same point crossed by Courtney on both days.
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A crane used 250,000 Joules of work to move a beam to the top of a building in 20 seconds. How much power did the crane use?
a) 5,000,000 W
b) 5,000 W
c) 50 J
d) 12,500 W
Answer:
12500W
Explanation:
Given parameters:
Work done = 250000J
Time taken = 20s
Unknown:
Power of the crane = ?
Solution:
Power is the defined as the rate at which work is being done;
Mathematically;
Power = [tex]\frac{work done}{time }[/tex]
insert the parameters and solve;
Power = [tex]\frac{250000}{20}[/tex] = 12500W
Heat flows from __________ energy to __________ energy.
A. higher, lower
B. lower, higher
Answer:
A. higher, lower
Explanation:
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Two cats jump off a roof that is 23m off the ground. Cat A jumps directly up with a velocity of 7m/s, and cat B jumps directly down with a velocity of 7m/s. How far up does cat A go? How fast does cat A go just before it hits the ground? How fast does cat B go just before it hits the ground? How much longer is cat A in the air than cat B?
(a) The height reached by cat A is 2.5 m.
(b) The speed of cat A before it hits the ground is 36.4 m/s.
(c) The speed of cat B before it hits the ground is 22.39 m/s.
(d) The time spent in air by cat A than cat B is 1.43 seconds.
Time of motion of cat AThe time of motion of cat A is calculated as follows;
h = vt - ¹/₂gt
-23 = 7t - 4.9t²
4.9t² - 7t - 23 = 0
solve the quadratic equation using formula method;
a = 4.9, b = -7, c = - 23
t = 3.0 seconds
Time of motion of cat BThe time of motion of cat B is calculated as follows;
h = vt - ¹/₂gt
23 = 7t + 4.9t²
4.9t² + 7t - 23 = 0
solve the quadratic equation using formula method;
a = 4.9, b = 7, c = -23
t = 1.57 seconds
Height reached by cat Ah = u²/2g
h = (7²)/(2 x 9.8)
h = 2.5 m
Speed of cat A before it hits the groundv = u + gt
v = 7 + 3(9.8)
v = 36.4 m/s
Speed of cat B before it hits the groundv = u + gt
v = 7 + 1.57(9.8)
v = 22.39 m/s
Time spent in air by cat A than cat B
Time difference = 3 s - 1.57 s = 1.43 seconds
Thus, the height reached by cat A is 2.5 m.
The speed of cat A before it hits the ground is 36.4 m/s.
The speed of cat B before it hits the ground is 22.39 m/s.
The time spent in air by cat A than cat B is 1.43 seconds.
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