The average speed of a bus traveling a distance of 15.0 km in 45.0 min is 20 km/hour.
What is speed?The speed of an object, also known as v in kinematics, is the size of the change in that object's position over time or the size of the change in that object's position per unit of time, making it a scalar quantity.
The distance travelled by an object in a time interval is divided by the length of the interval to determine its average speed.
Distance travelled by the bike = 15.0 km
Time taken by the object = 45.0 minute = (45.0 ÷ 60) hour = 0.75 hour
Hence, the average speed of the object = distance travelled / time taken
= 15.0 km/0.75 hour
= 20 km/hour,
Therefore, the average speed of a bus traveling a distance of15.0 km in 45.0 min is 20 km/hour.
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Geophysicists have estimated that the temperature at the center of the Earth's
core is at least 5000°C. Express this temperature in Fahrenheit degrees.
CA 8703 °F
B 9032°F
C 10,087°F
D 5609°F
Answer: B. 9032°F
Explanation:
First we take down the data made available to us.
Estimated temperature of the Earth's core = 5000° Celsius
Now to express this temperature in Fahrenheit, we make use of the formula;
[°F] = [°C] × 9/5 + 32
Where
[°F] is temperature in Fahrenheit and
[°C] is temperature in Celsius
So we just input our figure into the formula
[°F] = [5000°] × 9/5 + 32
°F = 5000 × 1.8 + 32
°F = 9000 + 32
°F = 9032°
So 5000° Celsius is expressed as 9032° Fahrenheit
A person jumps out a fourth-story window 14 m above a firefighter safety net. The survivor stretches the net 1.8 m before coming to rest. what was the deceleration experienced by the survivor? Use g = 9.8 m/s2 Calculate to one decimal.
Answer:
The deceleration is [tex]a = - 76.27 m/s^2[/tex]
Explanation:
From the question we are told that
The height above firefighter safety net is [tex]H = 14 \ m[/tex]
The length by which the net is stretched is [tex]s = 1.8 \ m[/tex]
From the law of energy conservation
[tex]KE_T + PE_T = KE_B + PE_B[/tex]
Where [tex]KE_T[/tex] is the kinetic energy of the person before jumping which equal to zero(because to kinetic energy at maximum height )
and [tex]PE_T[/tex] is the potential energy of the before jumping which is mathematically represented at
[tex]PE_T = mg H[/tex]
and [tex]KE_B[/tex] is the kinetic energy of the person just before landing on the safety net which is mathematically represented at
[tex]KE_B = \frac{1}{2} m v^2[/tex]
and [tex]PE_B[/tex] is the potential energy of the person as he lands on the safety net which has a value of zero (because it is converted to kinetic energy )
So the above equation becomes
[tex]mgH = \frac{1}{2} m v^2[/tex]
=> [tex]v = \sqrt{2 gH }[/tex]
substituting values
[tex]v = 16.57 m/s[/tex]
Applying the equation o motion
[tex]v_f = v + 2 a s[/tex]
Now the final velocity is zero because the person comes to rest
So
[tex]0 = 16.57 + 2 * a * 1.8[/tex]
[tex]a = - \frac{16.57^2 }{2 * 1.8}[/tex]
[tex]a = - 76.27 m/s^2[/tex]
A small object begins a free-fall from a height of =81.5 m at 0=0 s . After τ=2.20 s , a second small object is launched vertically up from the ground with an initial velocity of 0=40.0 m/s . At what height from the ground will the two objects first meet?
Answer:
33.2 m
Explanation:
For the first object:
y₀ = 81.5 m
v₀ = 0 m/s
a = -9.8 m/s²
t₀ = 0 s
y = y₀ + v₀ t + ½ at²
y = 81.5 − 4.9t²
For the second object:
y₀ = 0 m
v₀ = 40.0 m/s
a = -9.8 m/s²
t₀ = 2.20 s
y = y₀ + v₀ t + ½ at²
y = 40(t−2.2) − 4.9(t−2.2)²
When they meet:
81.5 − 4.9t² = 40(t−2.2) − 4.9(t−2.2)²
81.5 − 4.9t² = 40t − 88 − 4.9 (t² − 4.4t + 4.84)
81.5 − 4.9t² = 40t − 88 − 4.9t² + 21.56t − 23.716
81.5 = 61.56t − 111.716
193.216 = 61.56t
t = 3.139
The position at that time is:
y = 81.5 − 4.9(3.139)²
y = 33.2
A physics student standing on the edge of a cliff throws a stone vertically downward with an initial speed of 10 m/s. The instant before the stone hits the ground below, it is traveling at a speed of 30 m/s. if the physics student were to throw the rock horizontally outward from the cliff instead, with the same initial speed of 10 m/s, how fast would the stone be traveling just before it hits the ground
Answer:
The velocity just before hitting the ground is [tex]v_f = 30 m/s[/tex]
Explanation:
From the question we are told that
The initial speed is [tex]u = 10 m/s[/tex]
The final speed is [tex]v = 30 \ m/s[/tex]
From the equations of motion we have that
[tex]v^2 =u^2 + 2as[/tex]
Where s is the distance travelled which is the height of the cliff
So making it the subject of the the formula we have that
[tex]s = \frac{v^2 - u^2 }{2a}[/tex]
Where a is the acceleration due to gravity with a value [tex]a = 9.8m/s^2[/tex]
So
[tex]s = \frac{30^2 - 10^2 }{2 * 9.8 }[/tex]
[tex]s = 40.8 \ m[/tex]
Now we are told that was through horizontally with a speed of
[tex]v_x =10 m/s[/tex]
Which implies that this would be its velocity horizontally through out the motion
Now it final velocity vertically can be mathematically evaluated as
[tex]v_y = \sqrt{2as}[/tex]
Substituting values
[tex]v_y = \sqrt{(2 * 9.8 * 40.8)}[/tex]
[tex]v_y = 28.3 \ m/s[/tex]
The resultant final velocity is mathematically evaluated as
[tex]v_f = \sqrt{v_x^2 + v_y^2}[/tex]
Substituting values
[tex]v_f = \sqrt{10^2 + 28.3^2}[/tex]
[tex]v_f = 30 m/s[/tex]
A tennis player serves a tennis ball such that it is moving horizontally when it leaves the racquet. When the ball travels a horizontal distance of 13 m, it has dropped 56 cm from its original height when it left the racquet. What was the initial speed, in m/s, of the tennis ball
Answer:
The initial velocity is 38.46 m/s.
Explanation:
The horizontal distance travel by the tennis ball = 13 m
The height at which the tennis ball dropped = 56 cm
Now calculate the initial speed of tennis ball.
The vertical velocity is zero.
Below is the calculation. Here, first convert centimetre into kilometre. So, height at which ball dropped is 0.56 km.
[tex]v = \sqrt{2 \times 9.8 \times 0.56} = 3.32 m/s \\[/tex]
[tex]t = \frac{3.32}{9.8} = 0.338s \\[/tex]
[tex]Ux \times t = 13 \\[/tex]
[tex]Ux = \frac{13}{0.338} = 38.46 m/s = Initial velocity.[/tex]
Under electrostatic conditions, the electric field just outside the surface of any charged conductor
A. is always zero because the electric field is zero inside conductors
B. can have non zero components perpendicular to and parallel to the surface of the conductor
C. is always perpendicular to the surface of the conductor
D. is always parallel to the surface
E. is perpendicular to the surface of the conductor only if it is a sphere, a cylinder, or a flat sheet.
Answer:
C. is always perpendicular to the surface of the conductor
Explanation:
On a charged conductor , electric charge is uniformly distributed on its surface . The lines of forces are also uniformly distributed on all directions . They repel each other so they emerge perpendicular to the surface so that they do nor cut each other and at the same time they remain at maximum distance from each other.
A cube, 1 m on each edge, is held 0.75 m below the surface of a pool of water by a rope. The mass of the cube is 700 kg, and the weight distribution is such that one face remains parallel to the surface of the water. a. Find the tension in the rope. b. Assuming the rope is cut, how far will the cube protrude from the water
Answer:
Explanation:
The mass of cube = 700 kg
volume = 1 m³
density = 700 kg / m²
Its density is less than that of water so it will try to float on the surface .
Tension in rope will be equal to net upward force
upthrust = volume x density of water x g
= 1 x 10³ x 9.8
= 9800 N
weight of cube = mass x g
= 700 x 9.8
= 6860 N .
Net upward force = 9800 - 6860
= 2940 N.
Tension in the rope = 2940 N.
Rope will hold the cube inside and not allow it to go outside water .
b )
If rope is cut , cube being lighter , will float on surface of water .
Part of cube inside water while floating
= 6860 / 9800
= .7
.7 m will remain inside water
part floating outside
= 1 - 0.7
= 0.3 m .
Which of the following is the healthiest type of carbohydrate?
A Bread made with white flour
B Rice made with whole grains
C Cereal made with refined grains
D White rice
Answer:
C
Explanation:
Cereal made with refined grains is the healthiest type of carbohydrate.
What are carbohydrates?
A carbohydrate is defined as a bio-molecule which consists of carbon,hydrogen and oxygen atoms which are usually in the ratio of 2:1 with the empirical formula C[tex]_n[/tex](H₂O)[tex]_n[/tex].
This term is most commonly used in field of biochemistry as a synonym of saccharide which is a group of sugars, starch and cellulose.
They perform various functions in living organisms. They serve as an energy source and as well as structural components . They are a key component in providing nutrition and are found in wide variety of natural as well as processed foods.
Carbohydrates occur as cellulose in the cell walls of plants and is one of the components of insoluble dietary fibers.
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(10 points) A spring with a 7-kg mass and a damping constant 12 can be held stretched 1 meters beyond its natural length by a force of 4 newtons. Suppose the spring is stretched 2 meters beyond its natural length and then released with zero velocity. In the notation of the text, what is the value c2−4mk? m2kg2/sec2 Find the position of the mass, in meters, after t seconds. Your answer should be a function of the variable t of the form c1eαt+c2eβt where α= (the larger of the two) β=
Answer:
......................
I need help plz help me out 10 points!!!!!!!
Answer:
The answer is diffraction
Explanation:
Answer:
The answer is diffraction
Explanation:
I did the test! HOPE THIS HELPS!
An object has a mass of 5 kg. What force is needed to accelerate it at 6 m/s?
Answer:30N
Explanation:
Mass=5kg
Acceleration=6m/s^2
Force=mass x acceleration
Force=5 x 6
Force=30N
Answer:
30n
Explanation:
Mass=5kg
Acceleration=6m/s^2
Force=mass x acceleration
Force=5 x 6
Force=30N
Doubling the amplitude of a sound wave will ?
A) Double the speed of the sound and cause it to have a higher pitch
B) Havel the speed of sound and cause it to have a lower pitch
C) Leave the speed of sound unchanged, but cause the sound to be louder
D) Leave the speed of sound unchanged and cause the sound to have a lower pitch
Answer:
(C) is correct option.
Explanation:
The loudness of sound wave determines its amplitude. If the sound is loud, it will have more amplitude while if the sound is soft, it will have less amplitude.
On doubling the amplitude of sound wave, it will become more loud.
Doubling the amplitude of a sound wave will leave the speed of sound unchanged, but cause the sound to be louder. Hence, the correct option is (C).
in the figure calculates the acceleration of the block friction not today
Answer:
A fan pushes hot air out of a vent and into a room. The hot air displaces cold air in the room, causing the cold air to move closer to the floor.
The hot air displacing the cold air is an example of transfer by
Explanation:
also the answer is hit my dm on ig
Minority group
A shared identity based on
cultural elements such as
heritage, language, and
religion
Ethnicity
A socially constructed
group of people who share
physical characteristics
that are considered
significant by a society
and that are used to
distinguish them from
other groups
Majority group
People who are singled
out for unequal treatment
and who regard
themselves as objects of
collective discrimination
Race
A group's subset that
consists of more than half
of the entire group's
members
Answer:
Minority group - People who are singled out for unequal treatment and who regard themselves as objects of collective discrimination.
Ethnicity - A shared identity based on cultural elements such as heritage, language, and religion.
Majority group - A group's subset that consists of more than half of the entire group's members.
Race - A socially constructed group of people who share physical characteristics that are considered significant by a society and that are used to distinguish them from other groups.
Explanation:
To better understand the above-mentioned definitions we would use some examples:
Elder people can be considered as a minority group in the United States because of their reduced status as a consequence of popular discrimination and prejudice against them. In contrast to them, young men consisting of more than half the population in the age category is an example of the majority group.
Groups of people like Hispanic Americans, Jews, Italian America, Irish are some examples of people belonging to different ethnic backgrounds residing in the U.S.
African Americans who are distinguished based on their skin color is an example of race.
28.18. Consider two conducting spheres with one having a larger radius than the other. Both spheres carry the same amount of excess charge. Which one of the following statements concerning the electric potential of the two spheres is true?a) The electric potential of the larger sphere is greater than that of the smaller sphere.b) The electric potential of the larger sphere is the same as that of the smaller sphere.c) The electric potential of the larger sphere is less than that of the smaller sphere.
Answer:
b) The electric potential of the larger sphere is the same as that of the smaller sphere
Explanation:
An electric potential is the amount of work needed to move a unit of charge from a reference point to a specific point inside the field without producing an acceleration. The reference point is typically the Earth or a point at infinity, although any point can be used.
It is proportional to the charge on a particle and inversely proportional to its relative distance to the electric field.
E = kQ/r
Where k = 1/4¶E°
Where E° is permittivity of free space 8.85x10^-12 F/m
You go grab a car door handle in the summer (energy transfer to heat up the handle conduction) and it burns you through _____ energy transfer.
A. Radiation-transfer of energy (heat) through space by electromagnetic rays.
B. Conduction-the transfer of energy (heat) through the matter by molecules energy (touch).
C. Convection-the transfer of heat movement of mass or substance (motion).
I think the answer is A
Which of the following statements are characteristics of magnetic fields? Select all that apply.
Magnetic fields point from the north pole to the south pole of a magnet.
The earth's magnetic field has no effect on the electron rays coming from the sun.
An example of the Biot-Savart law is the effect of the earth's maghytic field on the electron rays coming from the sun.
The north pole of a magnet will be attracted to the south pole of the earth.
If a bar magnet is cut in half two magnets with like poles will be created.
Answer:
Magnetic fields point from the north pole to the south pole of a magnet.
An example of the Biot-Savart law is the effect of the earth's maghytic field on the electron rays coming from the sun.
The north pole of a magnet will be attracted to the south pole of the earth.
If a bar magnet is cut in half two magnets with like poles will be created
Explanation:
The magnetic field of Earth is due to the presence of iron in the core of the Earth.
The metal emits the magnetic waves from it and the North and South pole of the planet.
Both the poles emit the magnetic rays which create magnetic sheet around it. The Earth acts like a magnet bar if which is cut into two half, the planet will act like two magnets. Also, Biot Savarts's law states that the magnetic field does not affect the electron rays coming from the Sun.
Thus, the selected options are correct.
Answer:
ACDE
Explanation:
What parts are found in an electric generator
Here are a list of items I found.
some brushes
a armature
a permanent magnet
some slip rings
Answer:
A fan pushes hot air out of a vent and into a room. The hot air displaces cold air in the room, causing the cold air to move closer to the floor.
The hot air displacing the cold air is an example of transfer by
Explanation:
What is (9x10^9)(2.6x10^-6)(1.4x10^-6) / 36
Answer:
0.00091
Explanation:
(9x10^9) (2.6x10^-6) (1.4x10^-6) / 36
(9,000,000,000) (0.0000026) (0.0000014) /36
|
23,400(0.0000014) /36
|
0.03276 /36
|
0.00091
Alan leaves Los Angeles at 8:00 A.M. to drive to San Francisco 400 mi away. He manages to travel at a steady 50 mph in spite of traffic. Beth leaves Los Angeles at 9:00 A.M. and surprisingly manages to also drive at a constant speed, in this case 60 mph. (Knight 2.1) a. Who gets to San Francisco first? (Beth) b. How long does the first to arrive have to wait for the second? (20 minutes)
Answer:
a) Beth will reach before Alan
b)Beth has to wait 20 min for Alan to arrive
Explanation:
let 'd' be distance b/w Los Angeles and San Francisco i.e 400 mi
considering ,
Alan's speed [tex]v_A[/tex]=50mph
Beth's speed [tex]v_B[/tex]=60mph
->For Alan:
The time required [tex]t_A[/tex]= d/[tex]v_A[/tex]= 400/50 => 8h
-> For beth:
The time required [tex]t_B=\frac{d}{v_B} =\frac{400}{60} =>6\frac{2}{3} h[/tex] => 6h 40m
Alan will reach at 8:00 a.m +8h = 4:00p.m.
Beth will reach at 9:00 a.m +6h 40m= 3:40p.m.
a) Beth will reach before Alan
b)Beth has to wait 20 min for Alan to arrive
Which of the following statements are true? a. Kinematics is the science that studies forces and motion of particles and bodies. b. Speed is a vector quantity. c. The units of velocity are length divided by time. d. The term deceleration is commonly used to describe a negative acceleration.
Answer:
true. b, c and d
Explanation:
Let's review each statement separately
a) False. The kinematics studies the position, speed and acceleration of the bodies, but not what causes these changes
b) True. Velocity is the displacement between time, displacement is a vector, and time is a scalar, so the division between them gives a vector
c) True. speed is the displacement that is a length between time, so its unit is length / time
d) true desaceleration = - aceleration
As SCUBA divers go deeper underwater, the pressure from the weight of all the water above them increases tremendously which compresses the gases in their blood. What happens to the volume of gas in their blood as the diver rises quickly to the surface?
Answer:
The volume of gas in an early diving bell full of air at sea level is halved at 10 m according to Boyle’s law
Explanation:
;at 20 m pressure is 300 kPa absolute and the gas is compressed into one third the volume.
HOPE THIS HELPS i did this before
Word ProNems:
1. A car goes from 4.47 m/s to 17.9 m/s in 3 seconds.
a. Did this car speed up or slow down?
b. Should your answer be positive or negative? Explain your reasoning.
c. Calculate the acceleration of the car.
Answer:
a:it speed up
b:it should be positive since final
velocity is larger than initial velocity
c:acceleration is approximately 4.5
m/s^2
Explanation:
initial velocity=u=4.47m/s
Final velocity=v=17.9m/s
Time=t=3 seconds
a:the car speed up since the velocity
increased
b:change in velocity is positive
because final velocity is larger than
initial velocity
17.9-4.47=13.43 m/s
c: acceleration=(v-u)/t
acceleration=(17.9-4.47)/3
acceleration=13.43/3
acceleration=4.5 m/s^2
If a car goes from a velocity u to a velocity v, the change in velocity is expressed as;
[tex]\triangle v =v-u[/tex]
Given
final velocity v = 17.9m/s
initial velocity u = 4.47m/s
[tex]\triangle v = 17.9-4.47\\\triangle v =13.43m/s[/tex]
a) Since the change in velocity is a positive value, this shows that the car speeds up.
b) The answer should be positive since the final velocity is greater than the initial velocity.
c) Acceleration is the change in velocity with respect to time
[tex]a=\frac{v-u}{t}\\a=\frac{17.9-4.47}{3} \\a=\frac{13.43}{3}\\a= 4.48m/s^2[/tex]
Hence the acceleration of the car is 4.48m/s²
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7. A light source has two spectral components, one with unknown wavelength and the other with wavelength 620 nm. When light from the source is incident to a thin rectangular slit, a screen behind the slit shows the second diffraction minimum from the 620 nm component at the exact same location as the third diffraction minimum from the unknown wavelength component. What is the unknown wavelength?
Answer:
Explanation:
Problem relates to diffraction of light . Location for 2 nd diffraction minima is
[tex]x=2\times\frac{\lambda D}{d}[/tex] where λ is wavelength of light , D is distance of screen , d is slit width .
Puting the values
[tex]x=2\times\frac{620D}{d}[/tex]
for unknown wavelength , position of third diffraction is
[tex]x=3\times\frac{\lambda D}{d}[/tex]
from these two equations
[tex]x=2\times\frac{620D}{d}[/tex][tex]=3\times\frac{\lambda D}{d}[/tex]
λ = 413.33 nm .
Which of the following is not true about of the use of MRI in medicine?
1) It produces no negative side-effects on the human body
2) It produces high resolution images of soft tissues
3) It is very cheap
4) It requires very strong magnetic fields
Answer:
3) False. It is expensive since it requires sophisticated equipment and very low temperatures
Explanation:
Nuclear magnetic resonance imaging measurements consist of magnetic resonance imaging to analyze tissues by the transition of the unpaired electron at carbon 13, giving information on the structure and composition of tissues. This information is processed in computers and transformed into images.
So the physical measurement is the MRN
Now we can analyze the statements in the problem
1) True by itself a magnetic measurement is non-invasive
2) True. Measuring carbon transitions has information about the soft tissue of the body
3) False. It is expensive since it requires sophisticated equipment and very low temperatures
4) Right. The applied magnetic field is high to be able to induce carbon transaction
In the figure calculates the acceleration of the block friction not today
Answer:
A fan pushes hot air out of a vent and into a room. The hot air displaces cold air in the room, causing the cold air to move closer to the floor.
The hot air displacing the cold air is an example of transfer by
Explanation:
In later years, motors improved and could be run directly from a 60 Hz power supply. As a result, 25 Hz power systems shrank and disappeared. However, there were many perfectly-good working 25 Hz motors in factories around the country that owners were not ready to discard. To keep them running, some users created their own 25 Hz power in the plant using motor-generator sets. A motor generator set consists of two machines connected on a common shaft, one acting as a motor and the other acting as a generator. If the two machines have different numbers of poles but exactly the same shaft speed, then the electrical frequency of the two machines will be different due to Equation (3-34). What combination of poles on the two machines could convert 60 Hz power to 25 Hz power?
Answer:
as in motor generaror are connected to same shaft then both machines are working with same speed
but number of poles are different with same speed means both machines are working with different frequencies
we know
frequency F = N*P/120
speed N = 82120F/P
given
motor speed = generator speed
120F1/P1 = 120F2/P2
F1/P1 = F2/P2
output frequency is 25 which is obtained from generator so F2=25
input frequency is 60 which is given to motor soF1=60
60/P1 = 25/P2
60/25 = P!/P2
P1/P2 = 12/5
multiply and divided by 2 becuase poles are even
P1/P2 = 12*2/5*2
=24/10
P1= 24 poles a
P2 =10 poles we get 25 hz frequency from 60 hz frequency
Q1. What is the frequency of rotation of 1000 loop coil of area 20cm2 in a magnetic field of 5T to
generate an emf that has a maximum value of 15.7V?
Answer:
Explanation:
Emf e generated in a coil with no of turn n and area A rotating in a magnetic field B with angular speed of ω is given by the expression
e = e₀ sinωt
where e₀ = nωAB which is the maximum emf generated
Putting the given values
15.7 = 1000xω x 20 x 10⁻² x 5
ω = .0157
frequency of rotation
= ω / 2π
= .0157 / 2 x 3.14
= .0025 /s
9 rotation / hour .
Who is having a hallucination?
O
A. Dominique, who doesn't know who she is anymore
O
B. Jasmine, who believes that she is a millionaire and is really a
princess
O
C. Damion, who suffers a concussion after a football game and has
memory problems
O
D. Terrance, who suffers from schizophrenia and sees faces looking
at him in the wall
Answer:
D. Terrance
Explanation:
This is because he is seeing things that aren't there.
Dominique has amnesia (useless it's just like an existential crisis)
Jasmine is having delusions? but she's not hallucinating.
Damion has I guess temporary amnesia? Maybe brain damage? but not hallucinations.
The figure shows a crane whose weight is 12.5 kN and center of gravity in G. (a) If the crane needs to suspend the 2.5kN drum, determine the reactions on the wheel in A and B when the boom is in the position shown.(b) Considering the same situation illustrated, what is the value of the maximum weight that the crane can suspend without tipping over?
Answer:
(a) Ra = 9.25 kN; Rb = 5.75 kN
(b) 26.7 kN
Explanation:
(a) Draw a free-body diagram of the crane. There are four forces:
Reaction Ra pushing up at A,
Reaction Rb pushing up at B,
Weight force 12.5 kN pulling down at G,
and weight force 2.5 kN pulling down at F.
Sum of moments about B in the counterclockwise direction:
∑τ = Iα
-Ra (0.66 m + 0.42 m + 2.52 m) + 12.5 kN (2.52 m + 0.42 m) − 2.5 kN ((3.6 m + 0.9 m) cos 30° − 2.52 m) = 0
-Ra (3.6 m) + 12.5 kN (2.94 m) − 2.5 kN (1.38 m) = 0
Ra = 9.25 kN
Sum of moments about A in the counterclockwise direction:
∑τ = Iα
Rb (0.66 m + 0.42 m + 2.52 m) − 12.5 kN (0.66 m) − 2.5 kN ((3.6 m + 0.9 m) cos 30° + 0.66 m + 0.42 m) = 0
Rb (3.6 m) − 12.5 kN (0.66 m) − 2.5 kN (4.98 m) = 0
Rb = 5.75 kN
Alternatively, you can use sum of the forces in the y direction as your second equation.
∑F = ma
Ra + Rb − 12.5 kN − 2.5 kN = 0
Ra + Rb = 15 kN
9.25 kN + Rb = 15 kN
Rb = 5.75 kN
However, you must be careful. If you make a mistake in the first equation, it will carry over to this equation.
(b) At the maximum weight, Ra = 0.
Sum of the moments about B in the counterclockwise direction:
∑τ = Iα
12.5 kN (2.52 m + 0.42 m) − F ((3.6 m + 0.9 m) cos 30° − 2.52 m) = 0
12.5 kN (2.94 m) − F (1.38 m) = 0
F = 26.7 kN
