Assuming the applied force is exerted parallel to the floor, by Newton's second law both the net vertical and net horizontal forces would be zero:
∑ F (horizontal) = p - f = 0 … … … because the desk is pushed at a constant speed
∑ F (vertical) = n - mg = 0 … … … because the desk doesn't move up or down
where p is the magnitude of the applied force, f is the mag. of kinetic friction, n is the mag. of the normal force due to contact between the floor and desk, and mg is the weight of the desk. We have
n = mg = (100 kg) g = 980 N
and the mag. of friction is proportional to n according to
f = 0.4 n = 392 N
Then the applied force p has magnitude
p = f = 392 N
An object of 4 cm length is placed at a distance of 18 cm in front of a convex mirror of radius of curvature 30 cm. Find the position of the image ,its nature and size?
Answer:
The position is 8.18cm from the mirror.
Nature is b=virtual
Size is 1.82cm
Explanation:
Note that for a convex mirror, the image distance and the focal length are negative;
Given
Object height H0 = 4cm
object distance u = 18cm
Radius of curvature R = 30cm
Since f = R/2
f = 30/2
f = -15cm
Recall that:
[tex]\frac{1}{f} =\frac{1}{u}+ \frac{1}{v}\\\frac{1}{-15}=\frac{1}{18}+\frac{1}{v} \\\frac{1}{v} =\frac{1}{-15} -\frac{1}{18}\\ \frac{1}{v} = \frac{-18-15}{270}\\\frac{1}{v} = \frac{-33}{270}\\v=\frac{-270}{33}\\v=-8.18cm[/tex]
Since the image distance is negative, this shows that the image is a virtual image.
To get the size:
[tex]\frac{H_1}{H_0}=\frac{v}{u}\\\frac{H_1}{4}=\frac{8.18}{18}\\18H_i=32.72\\H_i=\frac{32.72}{18}\\H_i= 1.82cm[/tex]
the resultant capacitance of four capacitorconnected in series is --------the smalest individual capacitance
Answer:
This question is misleading since
1/C = 1/C1 + 1/C2 + 1/C3 + 1/C4
so it would have to be less than the smallest individual capacitance
True or false: The maximum tensile force a solid, cylindrical wire can withstand increases as the thickness of the wire increases.
True
False
Answer:
True
Explanation:
The tensile stress, σ, on a solid cylindrical wire is given by the following relationship;
[tex]\sigma = \dfrac{F_t}{A_o}[/tex]
Where;
[tex]F_t[/tex] = The tensile force
[tex]A_o[/tex] = The original cross sectional area of the cylindrical wire = π·R²
R = The radius of the wire
Therefore;
[tex]F_t[/tex] = σ × [tex]A_o[/tex] = σ × π × R²
Therefore, the tensile force is directly proportional to the square of the radius of the cylindrical wire, and as the radius of the wire increases, which is by increasing the thickness of the wire, the tensile force is largely increased
The correct option is; True.
The direction equivalent to {40° W of S} is:
A. 40 ° E of S
B. 40° W of N
C. 40° E of N
D. 50° S of W
E. 50° E of N
Answer:
c
Explanation:
will mark brainliest. The speed of sound is 340 m/s where a tuning fork produces the second resonance position above a closed air column that is 49.8 cm in length. The frequency of the tuning fork is ___ Hz.
Answer:
Frequency of the tuning fork[second resonance] = 512 Hz (Approx.)
Explanation:
Given:
Speed of sound = 340 m/s
Length of resonance position above a closed air column = 49.8 cm = 0.498 m
Find:
Frequency of the tuning fork
Computation:
Frequency of the tuning fork[second resonance] = 3v / 4l
Frequency of the tuning fork[second resonance] = 3(340) / 4(0.498)
Frequency of the tuning fork[second resonance] = 512.04
Frequency of the tuning fork[second resonance] = 512 Hz (Approx.)
Answer:
The frequency is 512 Hz.
Explanation:
speed, v = 340 m/s
length, L = 49.8 cm = 0.498 m
let the frequency is f.
[tex]f =\frac{3 v}{4 L}\\\\f = \frac{3 \times 340 }{4\times 0.498}\\\\f = 512 Hz[/tex]
I’m steel, the solvent is And the solute is. .
Using your Periodic Table, which element below has the smallest atomic radius? A.) Sodium, B.) Chlorine, C.) Phosphorus, D.) Iron
the pages of a book are numbered 1 to 300. Each leaf is 0.1 mm thick . If each cover is 0.25 mm thick. what is the thickness of the book
Answer:
30.5mm
Explanation:
There are 300 pages, so to find the number of pages we do 0.1mm*300 to get 30mm. There are two covers in the book (the front and the back). 0.25mm*2 = 0.5mm. To determine the total thickness of the book we do 30mm+0.5mm to get a total of 30.5mm
Your answer is 30.5mm.
Answer:
15.5mm
Explanation:
there are 150 pages(one page has 2 sides so 300/2 = 150) and 2 covers
page's thickness is 0.1mm, cover's thickness is 0.25
so books thickness = 150*0.1+0.25*2 = 15.5mm
Which of the following are true about simile and metaphor? Select all that apply.
similes and metaphors make comparisons for emotional effect
simile uses "like" or "as": metaphor does not
similes and metaphors make comparisons to give us mental pictures
both are the same
Answer:
It is simile uses "like" or "as": metaphor does not
Explanation:
it just it
Answer:
third one
Explanation:
i cant think of anymore
Which sentence best describes a role of gravity in the formation of the
universe?
A. Gravity caused the universe to expand from a central point.
B. Gravity caused background microwave radiation to be emitted as
the universe formed.
C. Gravity caused galaxies to move apart from one another in a
symmetrical way.
D. Gravity caused stars to come together and galaxies to form after
the big bang
Answer:
I think it's option D
Explanation:
I think it's option D but not so sure
Give reasons for the following,
a. Pascal is a derived unit.
b. Mass is a fundamental quantity,
c. Unit of power is a derived unit,
d. Unit of length is a fundamental unit.
Answer:
a) Pascal is a derived unit because it is derived from the unit of force and area
b)Mass is a fundamental quantity because it doesn't depends upon others physical quantity and made up of only one unit
c) unit of power is a derived unit because they are dependent quantities
D) unit of length is a fundamental unit because it cannot be expressed in terms of another quantity.
what will be the magnitude of work if a force of 25N pulls a stone through a distance of 5m in its direction?
Explanation:
125 is your answer........
Drag each label to the correct location on the image. Identify the particles and characteristics on this model of an atom.
Positively charged
Electron
Proton
Neutron
Negatively charged
Answer:
cant see picture
Explanation:
Answer:
please add picture so i can help you
Explanation:
determine the work done when a forklift truck lifts a box of mass 350 kg a height of 2 m.
Answer:
work done = mgh
350×10×2
7000J
The work done by the forklift truck as it lifts the box to the given height is 6860J.
WorkWork is simply referred to as the displacement of an object when a push or pull force is applied to the object. It is the energy transferred from or to an object when force is applied to it along a displacement.
It is expressed as;
W = F × s
Where F is force and s is displacement
Given the data in the question;
Mass of box m = 350kgDisplacement s = 2mWork done W = ?We substitute our given values into the expression above.
W = F × s
But F = Weight = mass × acceleration due to gravity = mg
acceleration due to gravity ( g = 9.8m/s²)
Hence,
W = mg × s
W = 350kg × 9.8m/s² × 2m
W = 6860kgm²/s²
W = 6860J
Therefore, the work done by the forklift truck as it lifts the box to the given height is 6860J.
Learn more about Work: https://brainly.com/question/9942439
A bus Starts from rest. If the acceleration of bus become 10 m/s2 after 15 sec Calculate the final Velocity of the bus
Example to measure the interval of time of a small stone dropped from 1m height.
Answer:
The time required is 0.45 s.
Explanation:
Height, h = 1 m
initial velocity, u = m/s
Let the time is t.
Use second equation of motion
[tex]h = u t + 0.5 at^2\\\\1 = 0 +0.5 \times 9.8 \times t^2\\\\t = 0.45 s[/tex]
Even through there is equal and opposite reaction,usually the two forces are not seen balanced.Why?
Answer:
This may refer to a situation like:
"one person pushes a box, if there is equal and opposite reaction why the box moves and the person does not?"
Remember the second Newton's law:
F = m*a
suppose that the mass of the person is 3 times the mass of the box.
So, if the box has a mass M, the person will have a mass 3*M
Then the Newton's equation for the box when the person pushes with a force F is:
F = M*a
solving for the acceleration, we get:
F/M = a
While the person is also pushed by the box with a force with the same magnitude, then the equation for the person is:
F = (3*M)*a'
Solving for the acceleration, we get:
F/(3M) = a'
Now we can compare the acceleration of the box (F/M) with the acceleration of the person (F/3M).
Is easy to see that the acceleration of the box is 3 times the acceleration of the person.
So regardless of the fact that both the box and the person experience a force with the same magnitude, the box will move more due to this force.
This is why in situations like this, the forces do not seem balanced.
Encuentre la presion en la otra seccion estrecha si las velocidades en las secciones son de 0.50m\sy 2m\s
Answer:
ΔP = 1875 Pa, P₂ = P₁ - 1875
Explanation:
Let's use Bernoulli's equation, with the subscript 1 for the widest Mars and the subscript 2 for the narrowest part, suppose that the pipe is horizontal
P₁ + ½ ρ v₁² + ρ g y₁ = P₂ + ½ ρ v₂² + ρ g y₂
P₁ -P₂ = ½ ρ (v₂² - v₁²)
suppose the fluid is water
P₁ - P₂ = ½ 1000 (2² - 0.5²)
ΔP = 1875 Pa
this is the pressure difference between the two sections
the pressure in the narrowest section is
P₂ = P₁ - 1875
The thermal energy in a heat engine is used to move a piston. Which best describes why this is possible?
The increase in thermal energy results in an increase in pressure.
The decrease in thermal energy results in an increase in pressure.
The increase in thermal energy results in a decrease in pressure.
The decrease in thermal energy results in a decrease in pressure.
¿Cuál de las siguientes no es un tipo de fuerza de roce
Calculate the maximum absolute uncertainty for R if:
R = B - A
A = 32 +/- 2 seconds
B = 11 +/- 3 seconds
43 seconds
1 second
21 seconds
5 seconds
6 seconds
Answer:
ΔR = 5 s
Explanation:
The absolute uncertainty or error in an expression is
ΔR = | [tex]\frac{dR}{dB}[/tex] | ΔB + | [tex]\frac{dR}{dA}[/tex] | ΔA
the absolute value guarantees to take the unfavorable case, that is, the maximum error.
We look for the derivatives
[tex]\frac{dR}{dB}[/tex] = 1
[tex]\frac{dR}{dA}[/tex] = -1
we substitute
ΔR = 1 ΔB + 1 ΔA
of the data
ΔB = 3 s
ΔA = 2 s
ΔR = 3 + 2
ΔR = 5 s
PLEASE HEEEEEEELP
Assume that the velocity of the soda bottle falling from a height of 0.8 m will be 4 m/s. Record this velocity for each mass in Table A, and use it in calculating the predicted kinetic energy of the soda bottle for the masses of 0.125 kg, 0.250 kg, 0.375 kg, and 0.500 kg using the equation: KE=1/2 mv^2 When solving for kinetic energy (KE), m is mass, and v is the speed (or velocity).
KE = (0.5) m v²
given that : v = speed of the bottle in each case = 4 m/s when m = 0.125 kg
KE = (0.5) m v² = (0.5) (0.125) (4)² = 1 J
when m = 0.250 kg KE = (0.5) m v² = (0.5) (0.250) (4)² = 2 J
when m = 0.375 kg KE = (0.5) m v² = (0.5) (0.375) (4)² = 3 J
when m = 0.0.500 kg KE = (0.5) m v² = (0.5) (0.500) (4)² = 4 J
What is the volume of a cone with a height of 27 cm
and a radius of 13 cm? Round your answer to the
nearest tenth.
Use the button on your calculator to complete this
problem.
V =
cm?
Explanation:
→ Volume of cone = πr² × h/3
Here,
Radius (r) = 13 cmHeight (h) = 27 cm→ Volume of cone = π(13)² × 27/3 cm³
→ Volume of cone = 169π × 9 cm³
→ Volume of cone = 1521π cm³
→ Volume of cone = 1521 × 22/7 cm³
→ Volume of cone = 33462/7 cm³
→ Volume of cone = 4780.28 cm³
Answer:
4,778.4 is correct
Explanation:
After landing the aeroplane momentum becomes zero .Explain how the law of conservation helds here.
Answer:
see the explanation below
Explanation:
Momentum is a product of the mass of a particle and its velocity.
and also, momentum is a vector quantity; i.e. it has both magnitude and direction.
Now a plane in the air has both magnitude and velocity
When the plane lands the velocity will amount to zero although the mass is still very much intact
Now the mass* zero velocity= zero
Hence when a plane lands the momentum is zero
Which image illustrates refraction?
Answer:
B illustrates refraction
a car travel the first 20km with a speed of 40km/h and the next 40km with a speed of 80km/h . find the average speed
Answer:
average speed is 60km/h
Explanation:
you sum up the speed attained in each distance covered and divide it by 2 to get your answer
what change will occur in gravitational force between two bodies if mass of both object is doubled and distance between their center is halved
The gravitational force between 2 bodys decreases with distance between the two bodies.
f=G m1m2/r2
Answer:
if the distance between 2 objects is halved than the gravitation doubles ,as gravitation is inversely propotional, between the distance of 2 objects.An upright image which reduced in size 10 times occurred in a mirror. If the radius of
curvature of the mirror is 2 m, bow far is the object from the mirror?
How to solve?
Answer:
p = -9 m
Explanation:
For this exercise we use the equation of the geometric optics constructor
[tex]\frac{1}{f} = \frac{1}{p} + \frac{1}{q}[/tex]
where f is the focal length, p and q are the distance to the object and the image, respectively.
The mirrors the focal length is
f = R / 2
f = 2/2
f = 1 m
the magnification is
m =[tex]\frac{h'}{h} = - \frac{q}{p}[/tex]
indicates that the image was reduced h ’= h/10 implies that m = 1/10
[tex]\frac{1}{10} = - \frac{q}{p}[/tex]
we write our system of equations
p = -10q
1/1 = [tex]\frac{1}{p} + \frac{1}{q}[/tex]
we substitute
1 = [tex]\frac{1}{p} - \frac{10}{p}[/tex]
1 = 1/p (1 - 10)
1 = -9 / p
p = -9 m
What's the resultant of the 3 forces?
Answer:
Explanation:
We need to find the x-components of each of these vectors and then add them together, then we need to find the y-components of these vectors and then add them together. Let's get to that point first. That's hard enough for step 1, dontcha think?
The x-components are found by multiplying the magnitude of the vectors by the cosine of their respective angles, while the y components are found by multiplying the magnitude of the vectors by the sine of their respective angles.
Let's do the x-components for all the vectors first, so we get the x-component of the resultant vector:
[tex]F_{1x}=12 cos0[/tex] and
[tex]F_{1x}=12[/tex]
[tex]F_{2x}=9cos90[/tex] and
[tex]F_{2x}=0[/tex]
[tex]F_{3x}=15 cos126.87[/tex] and
[tex]F_{3x}=-9.0[/tex] (the angle of 126.87 is found by subtracting the 53.13 from 180, since angles are to be measured from the positive axis in a counterclockwise fashion).
That means that the x-component of the resultant vector, R, is 3.0
Now for the y-components:
[tex]F_{1y}=12sin0[/tex] and
[tex]F_{1y}=0[/tex]
[tex]F_{2y}=9sin90[/tex] and
[tex]F_{2y}=9[/tex]
[tex]F_{3y}=15sin126.87[/tex] and
[tex]F_{3y}=12[/tex]
That means that the y-component of the resultant vector, R, is 21.
Put them together in this way to find the resultant magnitude:
[tex]R_{mag}=\sqrt{(3.0)^2+(21)^2}[/tex] which gives us
[tex]R_{mag}=21[/tex] and now for the angle. Since both the x and y components of the resultant vector are positive, our angle will be where the x and y values are both positive in the x/y coordinate plane, which is Q1.
The angle, then:
[tex]tan^{-1}(\frac{21}{3.0})=82[/tex] degrees, and since we are QI, we do not add anything to this angle to maintain its accuracy.
To sum up: The resultant vector has a magnitude of 21 N at 82°
A steel ball is released just below the surface of thick oil in a cylinder.
During the first few centimetres of travel, what is the acceleration of the ball?
A constant and equal to 10 m / s2
B constant but less than 10 m / s2
C decreasing
D increasing
Answer:
Increasing
Explanation:
I Hope it Helps
