Answer:
(a) -6.67 [tex]m/s^2[/tex]
(b) 0.68
Explanation:
Given that the mass of the truck, [tex]m_1=8000[/tex] kg.
Mass of the package, [tex]m_2=3000[/tex] kg.
As the package does not slide, so the acceleration of both, truck as well as the package, is the same.
Let [tex]a\;\; m/s^2[/tex] is the acceleration of the combined mass, m.
[tex]m=m_1+m_2= 8000+3000=11000[/tex] kg.
The initial velocity of the combined mass, u= 20 m/s.
Time required to stop, t=3 seconds.
Final velocity, v=0.
Displacement traveled, s=50 m.
(a) As [tex]a=\frac {v-u}{t}[/tex]
[tex]\Rightarrow a=\frac{0-20}{3}=-\frac{20}{3} =6.67 m/s^2[/tex]
Hence the acceleration of the truck is [tex]-6.67 m/s^2.[/tex]
(b) Now, [tex]a=-6.67 m/s^2[/tex] is the acceleration of the package, this acceleration is due the frictional force, f.
Due to inertia, on application of break, the package have tendency to slide to left (in the direction of velocity). But the package does not slides, this is only due to the frictional force, f, which acts in the right direction ( opposite to the direction of velocity).
So, the magnitude of frictional force required on [tex]m_2[/tex] to avoid slide is
[tex]f=|m_2a|=\frac{20}{3}m_2\times(i)[/tex]
Now, let \mu be the minimum coefficient of the friction, so
The force due to friction, [tex]f_r= \mu N[/tex],
where [tex]\mu N[/tex] is the normal reaction.
[tex]N=m_2g[/tex], where g is the acceleration due to gravity.
So, [tex]f_r=\mu m_2g\cdots(ii)[/tex]
To avoid slide, [tex]f_r\geq f[/tex]
[tex]\Rightarrow \mu m_2g\geq\frac{20}{3}m_2[/tex] [from (i)and (ii)]
[tex]\Rightarrow \mu\geq \frac{20}{3\times 9.81}[/tex] [tex][ as \;g=9.81 m/s^2][/tex]
[tex]\Rightarrow \mu \geq 0.68[/tex]
Hence, the minimum value of coefficient of friction between packages and the truck os 0.68.
which change to a circuit is most likely to increase it electrical power
A: increase it's current and increase it's voltage
B: decrease it's current and increase it's voltage
C: decrease it's current and decrease it's voltage
D: increase it's current and decrease it's voltage
Answer:
A................
Explanation:
Hope this helps you
A. increase it's current and increase it's voltage
Explanation:
Which of the following is an example of a luminous object?
Dog
Tree
Candle
Moon
Answer:
Candle
Explanation:
The moon is an illuminated object, while a candle is a luminous object!
Answer:
Candle
Explanation:
I just took the test
Finding the area of a trapezoid on a velocity versus time graph will tell you
the ——————
of an object.
A. displacement
B. acceleration
C. velocity
D. distance
Attachment Lab:Conservation of Linear Momentum
Answer:
This is what I got the teacher hasn’t graded it yet so sorry if it’s not right
Explanation:
this is also for a Digital Electronics class
Answer:
Rt = 908.25 [ohm]
Explanation:
In order to solve this problem, we must remember that the resistors connected in series are added up arithmetically.
In this case, R2 and R3 are in series therefore.
R₂₃ = 200 + 470
R₂₃ = 670 [ohm]
Now this new resistor (R₂₃) is connected in parallel with the resistor R4. therefore we must use the following arithmetic expression, to add resistances in parallel.
[tex]\frac{1}{R_{4-23} }= \frac{1}{R_{4}}+\frac{1}{R_{23} } \\\frac{1}{R_{4-23} }=\frac{1}{1800}+\frac{1}{670} \\R_{4-23}=488.25[ohm][/tex]
In this way R₁, R₅ and R₄₋₂₃ are connected in series.
Rt = R₁ + R₅ + R₄₋₂₃
Rt = 150 + 270 + 488.25
Rt = 908.25 [ohm]
A student tries to measure the period of a pendulum that is already swinging
left and right. At the moment when the pendulum is fully to the left, she
counts 'One' and starts a stopwatch. She counts successive swings each time
that the pendulum returns to the left. When she counts ‘Ten' she stops the
stopwatch, and sees that it reads 12.0 s.
a. What was her mistake?
______________________________________________________________
b. What is the period of swing of this pendulum?
______________________________________________________________
c. In this particular experiment, explain the likely effect of her reaction time
on her answer.
Answer:
a. The student's mistake was that the student did not swing the pendulum and start the watch at the same time.
b. 1.2 s per swing.
c. The likely effect of her reaction time is that they will should subtract two seconds off the time.
Explanation:
The pupil made the error of not simultaneously starting the watch and swinging the pendulum.
What is pendulum?Pendulum is defined as a body that is suspended from a fixed point and moves back and forth while being pulled by gravity. The pendulum is used to gauge the gravitational pull because the force of gravity causes it to swing back toward its average position. A pendulum's time period can be used to tell the time because it is constant.
The swing of the pendulum is 1.2 sec. per swing. They should take two seconds off the timing due to her presumably slow reaction time. A pendulum's total time should be divided by the quantity of oscillations in order to determine its time period. When compared to a pendulum with a shorter string, the one back and forth cycle of a longer-stringed pendulum requires more time to complete.
Thus, the pupil made the error of not simultaneously starting the watch and swinging the pendulum.
To learn more about pupil, refer to the link below:
https://brainly.com/question/27874242
#SPJ2
Just like Coke is a type of soda, __________ is a type of ___________.
A.concentration,.equilibrium
B..equilibrium, concentration
C.diffusion, osmosis
D.osmosis. diffusion
Answer:
osmosis diffusionExplanation:
ok it's correct
1.A runner has a displacement of 20 meters in 5 seconds, what is his velocity
during this time?
Answer:
The required velocity of runner is 4m/s.
In which image below is the angle of refraction the greatest?
Answer:
Explanation:
Angle of refraction is the angle made by refracted ray with the normal at the point of incidence . In this figure , refracted ray has been shown by line having arrow-head . Normal has been shown by broken line .
We observe that in figure D , angle made by refracted ray with normal is greatest . So figure D is the answer.
The image where the angle of refraction is the greatest is the image D
What is the angle of refraction?The angle of refraction is the angle that the refracted ray made with the x-axis.
The higher the angle between the refracted ray and the x-axis, the higher the angle of refraction and vice versa.
From the given diagram, we can see that the image where the angle of refraction is the greatest is the image D
Learn more on angle of refraction here: https://brainly.com/question/15838784
Define potential energy. Give its mathematical formula and SI unit.
Answer:
The type of mechanical energy that is possessed due to the virtue of motion or state of a body is known as potential energy.
Its formula: PE= mgh
Its SI unit is joule.
Hope it helps you..
Which of the following non-metals is used as a lubricant in powdered form?
a) Sulphur
b) lodine
c) Graphite
d) Silicon
Answer:
Graphite.
Explanation:
Graphite: "a gray crystalline allotropic form of carbon which occurs as a mineral in some rocks and can be made from coke. It is used as a solid lubricant, in pencils, and as a moderator in nuclear reactors."
What, exactly, is moving across the medium?
Answer:
So waves are everywhere. But what makes a wave a wave? What characteristics, properties, or behaviors are shared by the phenomena that we typically characterize as being a wave? How can waves be described in a manner that allows us to understand their basic nature and qualities?
A wave can be described as a disturbance that travels through a medium from one location to another location. Consider a slinky wave as an example of a wave. When the slinky is stretched from end to end and is held at rest, it assumes a natural position known as the equilibrium or rest position. The coils of the slinky naturally assume this position, spaced equally far apart. To introduce a wave into the slinky, the first particle is displaced or moved from its equilibrium or rest position. The particle might be moved upwards or downwards, forwards or backwards; but once moved, it is returned to its original equilibrium or rest position. The act of moving the first coil of the slinky in a given direction and then returning it to its equilibrium position creates a disturbance in the slinky. We can then observe this disturbance moving through the slinky from one end to the other. If the first coil of the slinky is given a single back-and-forth vibration, then we call the observed motion of the disturbance through the slinky a slinky pulse. A pulse is a single disturbance moving through a medium from one location to another location. However, if the first coil of the slinky is continuously and periodically vibrated in a back-and-forth manner, we would observe a repeating disturbance moving within the slinky that endures over some prolonged period of time. The repeating and periodic disturbance that moves through a medium from one location to another is referred to as a wave.
Hope That Helps!!
Explanation:
Which object might have the pattern of magnetic domains shown in the
image?
114 114
114 114
11 11
A. Cotton fabric near a magnet
O B. A piece of iron, not near a magnet
O C. A piece of iron near a magnet
D. Cotton fabric, not near a magnet
Answer: a piece of iron near a magnet
Explanation:
Se lanza una pelota y regresa al punto de partida 2.5 s después ¿Que altura máxima alcanzara? ¿a que altura se hallaba 1 segundo después del lanzamiento?
Answer:
a) [tex] y_{max} = 7.7 m [/tex]
b) y = 7.4 m
Explanation:
a) La altura máxima que alcanza la pelota se puede encontrar usando la siguiente ecuación:
[tex] y_{max} = y_{0} + v_{0y}t - \frac{1}{2}gt^{2} [/tex] (1)
En donde:
[tex]y_{0}[/tex]: es la altura inicial = 0
[tex]v_{0y}[/tex]: es la velocidad inicial en y
g: es la gravedad = 9.81 m/s²
t: es el tiempo
Primero debemos encontrar la velocidad inicial en y:
[tex] v_{fy} = v_{0y} - gt [/tex]
Sabiendo que la velocidad final en y es igual a cero (en la altura máxima), y con t = 1.25 s (la mitad del tiempo total) tenemos:
[tex] v_{0y} = gt = 9.81 m/s^{2}*1.25 s = 12.3 m/s [/tex]
Ahora, podemos encontrar la altura máxima:
[tex] y_{max} = v_{0y}t - \frac{1}{2}gt^{2} = 12.3 m/s*1.25 s - \frac{1}{2}9.81 m/s^{2}*(1.25 s)^{2} = 7.7 m [/tex]
b) Podemos encontrar la altura cuando t = 1 s con la misma ecuación (1):
[tex]y_{max} = y_{0} + v_{0y}t - \frac{1}{2}gt^{2} = 12.3 m/s*1 s - \frac{1}{2}9.81 m/s^{2}*(1 s)^{2} = 7.4 m[/tex]
Por lo tanto, la pelota se encontraba a 7.4 m luego de 1 segundo despúes del lanzamiento.
Espero que te sea de utilidad!
When a toy car is moving across a flat surface, what forces are acting on it (gravity, tension, spring, friction,air,normal,applied)?
Answer:
I believe gravity is acting on it
A car accelerates from 20 m/s to 80 m/s in 5 seconds. What is the
average acceleration of the car?
a 20 m/s2
b 12 m/s2
C 4 m/
d 16 m/s2
Answer:
12m/s2
Explanation:
:D (just a smiley, not answer d)
Momentum is a product of mass and....?
Answer:
Momentum is a product of mass and velocity.
Explanation:
Hope this helps you
Crown me as brainliest:)
what do electrons move from
Answer:
Negatively charged, to positively charged parts
Explanation:
Electrons are negative, negative is attracted to positive.
A block of cheese Bhangs from the ceiling by rope 1 A wheel of cheese Whangs from the block of
cheese by rope 2
What is the correct free body diagram for the block of cheese B?
URGENT
Answer:
Explanation:
KHAN ACADEMY
The correct free body diagram is option (B). There will only be two forces acting on cheese B.
Given that Cheese B hangs on rope 1. The weight of the cheese is balanced by the tension force on the rope. That is, the cheese experiences a force in the upward direction due to the tension on rope 1.Similarly, a wheel of cheese W hangs from block B by a rope 2. This rope has a tensional force that is balanced by the weight of the cheese W. This causes a downward pull on block B due to the tension on rope 2.By representing the tensional forces by the ropes 1 and 2 as [tex]F_{T1}[/tex] and [tex]F_{T2}[/tex] respectively, the correct free body diagram will be option B.
Learn more about free body diagrams here:
https://brainly.in/question/12953409
if 8000cm3 of liquid drains off an hour glass in one hour, what is the flow rate of water from the clock
Answer:
8000cm³/hr
Explanation:
Given parameters:
Volume of the liquid draining off per hour = 8000cm³
Time taken to drain off = 1hr
Unknown:
Flow rate = ?
Solution:
Flow rate is the volume of fluid that passes per unit of time.
Flow rate = [tex]\frac{volume of fluid}{time taken}[/tex]
Flow rate = [tex]\frac{8000cm^{3} }{1hr}[/tex]
Flow rate = 8000cm³/hr
What is a super dense gravitationally collapsed mass from which no light
can escape called?
1) neutron star
2) pulsar
3) supernova
4) black hole
Is a ball a wheel and axle if so how do you calculate the Mechanical Advantage of the ball? If not what kind of simple machine is a ball?
An object with an initial speed of 4.0 m/s accelerates uniformly at 2.0 m/s^2
in the direction of its motion for a distance of 5.0 meters. What is the final
speed of the object?
Why do we use insulators if they prevent the flow of electricity?
Answer:
letterman is shooting the kids
We use insulators to avoid being electrocuted. electricians use rubber gloves to avoid shock. Cables are insolated with rubber so you can hold them without getting shocked even if it is plugged in.
How do you measure the wavelength of wave?
Explanation:
by finding the distance between two successful crest
Answer:
the wavelength can be measured as the distance from crest to crest or from trough to trough , the wavelength of a wave can be measured as the distance from a point on a wave to the corresponding point on the next cycle of the wave.
Explanation:
Describe Kinetic Energy.
A skater of mass 60 kg has an initial velocity of 12 m/s. He slides on ice where the frictional force is 36 N. How far will the skater slide before he stops?
Answer:
d = 120 [m]
Explanation:
In order to solve this problem, we must use the theorem of work and energy conservation. Where the energy in the final state (when the skater stops) is equal to the sum of the mechanical energy in the initial state plus the work done on the skater in the initial state.
The mechanical energy is equal to the sum of the potential energy plus the kinetic energy. As the track is horizontal there is no unevenness, in this way, there is no potential energy.
E₁ + W₁₋₂ = E₂
where:
E₁ = mechanical energy in the initial state [J] (units of Joules)
W₁₋₂ = work done between the states 1 and 2 [J]
E₂ = mechanical energy in the final state = 0
E₁ = Ek = kinetic energy [J]
E₁ = 0.5*m*v²
where:
m = mass = 60 [kg]
v = initial velocity = 12 [m/s]
Now, the work done is given by the product of the friction force by the distance. In this case, the work is negative because the friction force is acting in opposite direction to the movement of the skater.
W₁₋₂ = -f*d
where:
f = friction force = 36 [N]
d = distance [m]
Now we have:
0.5*m*v² - (f*d) = 0
0.5*60*(12)² - (36*d) = 0
4320 = 36*d
d = 120 [m]
6. A total of 135 J of work is done on a gaseous refrigerant as it undergoes compression. If
the internal energy of the gas increases by 114 J during the process, what is the total amount
of energy transferred as heat? Has energy been added to or removed from the refrigerant as
heat?
Answer:
Eh = 21 [J]
Removed as heat.
Explanation:
This is a case of energy conservation, we have to take into account the energies that go in and out of the system. In this case, 135 [J] of energy are entered in the form of work of the compressor to the chamber where the refrigerant is compressed, now of these 135 [J] 114 [J] were used as internal energy, this internal energy is used to increase the pressure and temperature of the refrigerant.
In this way the rest of the energy of the 135 [J] was lost in the form of heat to determine this loss of energy, we simply perform the arithmetic subtraction.
Eh = 135 - 114 = 21 [J]
Eh = 21 [J]
What will happen if we increase the friction on a roller coaster?
A. The speed of the roller coaster will increase.
B. The speed of the roller coaster will decrease
C. The speed of the roller coaster will remain constant.
D. The roller coaster will fly away
Answer: B. The speed will decrease.
Explanation:
When you ride a roller coaster, the wheels rub/scrape the rails, creating heat as a result of friction. And friction will slow you down. So increasing the friction on a roller coaster would slow it down.
Answer:
B
Explanation:
Friction opposes motion therefore reducing motion
A battery and a resistor are wired into a circuit. The resistor dissipates 0.30 W. Now two batteries, each identical to the original one, are connected in series with the resistor. What power does it dissipate?
Answer:
1.2 W
Explanation:
Let the value of resistance be R , emf of battery be E
current i = E / R
power = i² R
= E² x R / R²
= E² / R
Given
E² / R = .30
when two batteries are connected
Total emf = 2E
current = 2E / R
Power = ( 2E / R )² x R
= 4 E² / R
= 4 x .30
= 1.2 W .