Answer:
a) 113N
b) 0.37
Explanation:
a) Using the Newton's second law:
\sum Fx =ma
Since the crate is not moving then its acceleration will be zero. The equation will become:
\sum Fx = 0
\sumFx = 0
Fm - Ff = 0.
Fm is the moving force
Ff is the frictional force
Fm = Ff
This means that the moving force is equal to the force of friction if the crate is static.
Since applied force is 113N, hence the magnitude of the static friction force will also be 113N
b) Using the formula
Ff = nR
n is the coefficient of friction
R is the reaction = mg
m is the mass of the crate = 31.2kg
g is the acceleration due to gravity = 9.8m/s²
R = 31.2 × 9.8
R = 305.76N
Recall that;
n = Ff/R
n = 113/305.76
n = 0.37
Hence the minimum possible value of the coefficient of static friction between the crate and the floor is 0.37
A steel wire in a piano has a length of 0.540 m and a mass of 4.800 ✕ 10−3 kg. To what tension must this wire be stretched so that the fundamental vibration corresponds to middle C (fC = 261.6 Hz on the chromatic musical scale)?
Answer:
T = 708.81 N
Explanation:
Given that,
Length of a steel wire in a piano, l =0.54 m
Mass, [tex]m=4.8\times 10^{-3}\ kg[/tex]
We need to find the tension must this wire be stretched so that the fundamental vibration corresponds to middle C, fc = 261.6 Hz
The equation for fundamental frequency is given by :
[tex]f=\dfrac{1}{2l}\times \sqrt{\dfrac{T}{\mu}} \\\\f=\dfrac{1}{2l}\times \sqrt{\dfrac{T}{\dfrac{m}{l}}} \\\\261.6=\dfrac{1}{2\times 0.54}\times \sqrt{\dfrac{T}{\dfrac{4.8\times 10^{-3}}{0.54}}} \\\\261.6\times 2\times 0.54=\sqrt{\dfrac{T}{\dfrac{4.8\times 10^{-3}}{0.54}}}\\\\282.528=\sqrt{\dfrac{T}{0.00888}} \\\\(282.528)^2=\dfrac{T}{0.00888}\\\\T=708.81\ N[/tex]
So, the required tension in the wire is 708.81 N.
Why is it easier to swim in sea than in a pond or river?
Answer:
Since sea water contains alot of salt the density of the sea water is higher as to the river water . So it makes it easier to swim in sea water
How much work, in kilojoules, went into thermal energy produced by friction?
The question is incomplete. Here is the complete question.
Suppose the mass of a loaded elevator is 1600 kg.
(a) What force, in Newtons, must be supplied by the elveator's cable to produce an acceleration of 0.745 m/s² upwards against a 185N frictional force?
(b) How much work, in joules, is done by the cable in lifting the elevator 21m?
(c) What is the final speed, in meters per second, of the elevator if it starts from rest?
(d) How much work, in kilojoules, went into thermal energy produced by friction?
Answer: (a) F = 1377 N
(b) W = 28917 J
(c) v = 5.6 m/s
(d) W = 3.885 kJ
Explanation:
(a) According to Newton's Second Law: [tex]F_{net}=m.a[/tex], in which, [tex]F_{net}[/tex] is the vetorial sum of all the forces in a system and its unit is [F] = kg.m/s² or newton (N).
In the elevator's case, and assuming going upwards is positive:
[tex]F-F_{f}=m.a[/tex]
F - 185 = 1600(0.745)
F = 1377 N
For an elevator to produce an acceleration of 0.745m/s² upwards, the cables have to supply a force of 1377 newtons.
(b) Work is the energy transferred to an object while is being moved. It is calculated as: W = F.s. Its unit is [W] = N.m or Joule (J)
In the elevator's cable:
W = 1377.21
W = 28917 J
The work done by the elevator's cable is W = 28917 joules.
(c) Acceleration is variation in velocity along time. Since we know the displacement of the elevator:
[tex]v^{2}=v_{0}^{2}+2a\Delta x[/tex]
where:
v₀ is initial velocity, which is this case v₀=0 because it starts from rest;
a is acceleration;
Δx is the displacement
Replacing values:
[tex]v^{2}=2(0.745)(21)[/tex]
[tex]v=\sqrt{31.29}[/tex]
v = 5.6 m/s
Final speed of the elevator is 5.6 m/s.
(d) [tex]W=F_{f}.s[/tex]
W = 185(21)
W = 3885 J
Work transferred into thermal energy because of friction is W = 3.885 kJ.
A circuit with a 12 V battery and lamp has a current of 3 A. What is the resistance of the lamp?
PLEASE HELP!!
To conclude, how would you explain
electromagnetic induction to a 5 year old?
words to include: magnets, electricity, and
change.
Answer:
fgdyauqushxhxxgxggxgxgxgsgsysysy
sysydyydydysysysysyxhxyt56fys7w727ueudu
A 1000 kg car moving at 108 km/h jams on its brakes and comes to a stop. How much work was done by friction?
Answer:
The work done by friction was [tex]-4.5\times10^{5}\ J[/tex]
Explanation:
Given that,
Mass of car = 1000 kg
Initial speed of car =108 km/h =30 m/s
When the car is stop by brakes.
Then, final speed of car will be zero.
We need to calculate the work done by friction
Using formula of work done
[tex]W=\Delta KE[/tex]
[tex]W=K.E_{f}-K.E_{i}[/tex]
[tex]W=\dfrac{1}{2}mv_{f}^2-\dfrac{1}{2}mv_{f}^2[/tex]
Put the value of m and v
[tex]W=0-\dfrac{1}{2}\times1000\times(30)^2[/tex]
[tex]W=-450000 \ J[/tex]
[tex]W=-4.5\times10^{5}\ J[/tex]
Hence, The work done by friction was [tex]-4.5\times10^{5}\ J[/tex]
A boy takes his dog for a walk. The dog pulls with 30N of force to the right and the boy pulls backward with 18 N of force.
Net Force = (your answer)
Body Diagram or Explanation = (your answer)
Answer:
Answer is in photo
Explanation:
How does thermal energy change matter?
Answer:
maxed out
Explanation:
Q1: An object is in a uniform circular motion. Which of the following statements must be
true?
Answer:
it has constant angular velocity
Explanation:
an object moving in a uniform circular motion moves with constant angular velocity about a point
A thin-walled vessel of volume V contains N particles which slowly leak out of a small hole of area A. No particles enter the volume through the hole. Find the time required for the number of particles to decrease to N/2. Express your answer in terms of A, V, and v.
Answer:
[tex]\frac{V}{2av}[/tex]
Explanation:
From the question we are told that
Volume V
Contains N particles
Leaks from a small hole of area A
Generally the equation for Flow rate is given as
Volume Flow Rate [tex]V_r = A * v[/tex]
Mathematically we find the time taken to flow half way which is given by
[tex]\frac{(V/2)}{A*v}[/tex]
Therefore the time taken is
[tex]\frac{V}{2av}[/tex]
If a person throws a wiffle ball and a tennis ball with the same speed, which object would travel with more kinetic
energy? Justify your selection
Answer:
The tennis ball will have more kinetic energy
Explanation:
It will have more kinetic energy because the tennis ball is more heavier than a wiffle ball. Furthermore, objects that are heavy will have more kinetic energy than objects that are light. Therefore, the tennis ball is the correct answer.
The tennis ball will have more kinetic energy as compared to the wiffle ball, because tennis ball is more heavier.
The energy possessed by any object due to virtue of its motion is known as kinetic energy. The standard expression for the kinetic energy is given as,
[tex]KE = \dfrac{1}{2}mv^{2}[/tex]
Here,
m is the mass of balls.
v is the speed of balls.
Clearly the kinetic energy of any object is dependent on the mass and velocity. So with same velocity, the heavier object will have more kinetic energy. Since, the tennis ball is more heavier as compared to the wiffle ball, therefore kinetic energy of tennis ball will be more.
Thus, we can conclude that the tennis ball will have more kinetic energy as compared to the wiffle ball, because tennis ball is more heavier.
Learn more about the kinetic energy here:
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The y-component of the force F which a person exerts on the handle of the box wrench is known to be 70 lb. Determine the x-component and the magnitude of F.
Answer:
Fx = 121.24lb
F = 140lb
Explanation:
Since we are not given the angles subtended by the force, we can assume it to be 30 degrees.
The y component of the force expressed by the formula:
Fy = Fsintheta
Given the y-component of the force F to bee 70lb
70lb = Fsintheta
Get magnitude of the force
F = 70/sin theta
F = 70/sin 30
F = 70/0.5
F = 140lb
Get the x-component of the force
Fx = Fcos theta
Fx = 140cos 30
Fx = 140(0.8660)
Fx = 1,212.4lb
Hence the x-component of the force sis 121.24lb
Note that the angle used was assumed. Other values can as well be used
How many hours will it take to fill a cubic vat of 15.7 ft edge length with a liquid that has a density of 1.31 g/mL and is spilling at a rate of 2.30 kg/s
Answer:
240 s or 4 minutes.
Explanation:
Given that
Volume of the cubic vat is 15.7³ = 3869.893 ft³
Density of the liquid is 1.31 g/mL
For easier calculations, we need to convert the density from g/mL to ft³
conversion factors shall be CUBED in order to do it!
We know that
1 inch = 2.54 cm, and
1 foot = 12 in
This means that
1.31 g/cm³ * 2.54³ cm³/in³ * 12³ in³/ft³
= 37095.069 g/ft³
Lastly,
We use this conversion method
1 second/ 2300 grams * 37095.069 g/ft = 16.13 ft³/s
Bringing down the volume of the cube, we use it to divide, and thus
3869.893 / 16.13 = 240 seconds
240 seconds = 4 minutes
A tennis player on serve tosses a ball straight up. While the ball is in free fall, its acceleration does which of the following?
a. decreasesb. remains constant c. increases then decreasesd. increasese. decreases then increases
Answer:
acceleration remains constant at g= 9.8m/s²
velocity however ...increases
An alpha particle has twice the charge of a beta particle. Why does the former deflect less than the latter when passing between electrically charged plates, assuming they both have the same speed?
Kelli drew a diagram to compare cast and imprint fossils. Which label belongs in the area marked Y? Involves minerals replacing remains of organism Takes millions of years to form Gives evidence of organism's activity Involves mold filling with minerals and sediment
Answer:
D. Involves mold filling with minerals and sediment
Explanation:
The given part y is in the inter region of the circle labelled cast and imprints. Thus, it belongs to both. Cast fossils are a type of imprint fossils which are filled with minerals from sediments and hardens to form the fossils. Thus, option d is correct.
What are fossils?Fossils are decomposed plants or animals or their imprints indicating their actions such as footprints, shells etc. There are broadly two types of fossils namely body fossils and trace fossils.
Body fossils are decomposed body parts of animals or plants such as bones, tree branches, skull etc. Trace fossils are imprints of the animals or plants such as footprints, shells, caves, skin etc.
Imprint fossils are the impression of any activities or behaviour of living things. shell, leaf, caves etc are imprint fossils. Cast fossils are formed by filling of imprint fossils with minerals reached from water and sediments and hardened to fossils. Therefore, the given area is cast fossil and option d is correct.
To find more on cast fossils, refer here:
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A 6 kg cart starting from rest rolls down a hill and at the bottom has a speed of 10 m/s. What is the height of the hill?
Answer:
h = 5.09 m
Explanation:
Applying the Law of conservation of energy to this situation, we can write:
[tex]Kinetic\ Energy\ Gained\ by\ the\ Cart = Potential\ Energy\ Lost\ by\ the\ Cart\\\frac{1}{2}mv^2 = mgh\\\\h = \frac{v^2}{2g}[/tex]
where,
h = height of the hill = ?
v = speed of cart at the end = 10 m/s
g = acceleration due to gravity = 9.81 m/s²
Therefore,
[tex]h = \frac{(10\ m/s)^2}{(2)(9.81\ m/s^2)}\\\\[/tex]
h = 5.09 m
Gravitational Potential Energy: You and your friend, who weighs the same as you, want to go to the top of the Eiffel Tower. Your friend takes the elevator straight up. You decide to walk up the spiral stairway, taking longer to do so. Compare the gravitational potential energy of you and your friend, after you both reach the top.
Answer:
Gravitational Potential Energy of both will be equal
Explanation:
The gravitational potential energy is given by the following formula:
[tex]P.E = mgh[/tex]
where,
P.E = Gravitational Potential Energy
m = mass of object
g = acceleration due to gravity
h = height of object
Therefore, the gravitational potential energy of an object depends only upon the height of the object and its mass.
Since, both masses and the heights achieved by both people is equal. Therefore, their gravitational potential energies will also be equal
why water in earthern pot remain cool in summer
Answer:
The water kept in an earthen pot seeps into the small pores in the pot and evaporates from the surface of the pot. The heat required for evaporation is taken from water inside the pot, thus cooling the water stored inside. This is the reason why on hot summer days water remains cool in earthen pot.
PLEASE MARK ME AS BRAINLIESTThe specific heat of aluminum is 0.90 J/gC . How much heat is given off when 25 grams of aluminum is cooled from 55 C to 25 C?
Answer:
Q = 675 [J]
Explanation:
We can calculate the amount of heat transfer by means of the following expression that includes the mass and temperature change in a body as a function of the specific heat.
[tex]Q=m*C_{p}*(T_{initial}-T_{final})[/tex]
where:
m = mass = 25 [gr]
Cp = specific heat = 0.9 [J/g*°C]
Tinitial = 55 [°C]
Tfinal = 25 [°C]
[tex]Q=25*0.9*(55-25)\\Q=675 [J][/tex]
To what temperature will 9400J of heat raise 3.5kg of water that is initially at 18.0?C? The specific heat of water is 4186 J/kg?C?.
Answer:
[tex]T_f=18.641^{\circ} C[/tex]
Explanation:
Given that,
Heat raised, Q = 9400 J
Mass, m = 3.5 kg
Initial temperature of water, [tex]T_i=18^{\circ} C[/tex]
The specific heat of water, [tex]c=4186\ J/kg^{\circ} C[/tex]
We need to find the final temperature of water. The heat required to raise the temperature is given by :
[tex]Q=mc\Delta T\\\\Q=mc(T_f-T_i)\\\\\dfrac{Q}{mc}=(T_f-T_i)\\\\T_f=\dfrac{Q}{mc}+T_i\\\\T_f=\dfrac{9400}{3.5\times 4186}+18\\\\=18.641^{\circ} C[/tex]
So, the final temperature is [tex]18.641^{\circ} C[/tex].
A tennis ball is hit with an initial velocity of 15 m/s at an angle of
40°. What is the horizontal distance of the ball after 2 seconds?
(round to the nearest meter)
Answer:
Horizontal acceleration is 0 in a projectile motion
Explanation:
first we have to find the horizontal velocity
15cos40 = 11.49ms^-1
and then use the following equation to find the distance
[tex]s = ut + \frac{1}{2} a {t}^{2} \\ s = 11.49 \times 2 \\s = 22.98m[/tex]
Given:
Initial velocity = 15 m/sAngle = 40°According to the question,
→ [tex]15 \ Cos 40^{\circ} = 11.49 \ m/s^{-1}[/tex]
By using the relation, we get
→ [tex]s = ut +\frac{1}{2}at^2[/tex]
By substituting the values, we get
[tex]= 11.49\times 2[/tex]
[tex]= 22.98 \ m[/tex]
Thus the response above is correct.
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PLEASE ANSWER ASAP BEFORE MY TEACHER AND MY MOM KILLES ME PLEASE ASAP
The first person with the right answer gets to be a brainlest
In the attachment there is a density column where there is colour
Question: tell me why is the red at the bottom of the density column if it is the least dense
The most dense thing inside the column is the little star. It's pink, and it's resting on the bottom of the cylinder.
The red part under the star is the solid base that the cylinder is standing in. It's probably wood or plastic, it's not free to move, and it's not involved in the experiment.
Answer: That is not meant to be red, it‘s the bottom of the beaker. The star is at the very bottom of the beaker. it’s just the base of the beaker.
What is the frequency of a wave with a wavelength of 36 m and a speed of 12 m/s?
3Hz
O .33HZ
O 432HZ
O 312HZ
Answer:
312hz
Explanation:
thanks me later
16x^2y^2-25a^2b^2
factorize the expression
Answer:
(4xy+5ab)(4xy-5ab)
Explanation:
16[tex]x^{2}[/tex][tex]y^{2}[/tex]-25[tex]a^{2}[/tex][tex]b^{2}[/tex]
4^2 is 16 and 5^2 is 25,
Also, (x-a)(x+a) = x^2-a^2
So, this factorized is:
(4xy+5ab)(4xy-5ab)
Hope this helps!
classify the simple machine knife
Answer:
Wedge
Explanation:
A knife is used to cut things into pieces or even cut two items apart.
Now, it is classified as a Wedge because a Wedge is defined as a simple machine that is used in pushing two objects apart. Some examples include axes, knives & chisels.
A car travels 60 km in the first 2 hours and 68 km in the next 2 hours. what is the cars average speed ?
Mental processes refers to
overt actions and reactions.
only animal behavior.
internal, covert processes.
outward behavior.
which items are matter?
Answer:
which items are matter?
battery , mobile phone
12. Why do you think afternoons are much warmer than the mornings or evenings?
Answer:
Afternoons are much warmer than the mornings or evenings is explained below in complete detail.
Explanation:
Because in the afternoon the sun is on the head and the beams of sunshine arrive straight to the earth so we exhibit warmer and in daylight and evening the sun is sparse to the earth so we observe colder than an afternoon. However, in the evening, when the sun is weak, I don't sense or experienced loads of heat and sunburn on body parts that are viewing the sun directly.