N4M.6 A board has one end wedged under a rock having a mass of 380 kg and is supported by another rock that touches the bottom side of the board at a point 85 cm from the end under the rock. The board is 4.5 m long, has a mass of about 22 kg, and projects essentially horizontally out over a river. Is it safe for an adult with a mass of 62 kg to stand at the unsupported end of the board

Answers

Answer 1

Answer:

it is safe to stand at the end of the table

Explanation:

For this exercise we use the rotational equilibrium condition

         Στ = 0

         W x₁ - w x₂ - w_table x₃ = 0

         M x₁ - m x₂ - m_table x₃ = 0

where the mass of the large rock is M = 380 kg and its distance to the pivot point x₁ = 850 cm = 0.85m

the mass of the man is 62 kg and the distance

            x₂ = 4.5 - 0.85

            x₂ = 3.65 m

the mass of the table (m_table = 22 kg) is at its geometric center

            x_{cm} = L/2 = 2.25 m

            x₃ = 2.25 -0.85

            x₃ = 1.4 m

let's look for the maximum mass of man

            m_{maximum} = [tex]\frac{ M x_1 -m_{table} x_3}{ x_2}[/tex]

let's calculate

             m_{maximum} = [tex]\frac{ 380 \ 0.85 - 22 \ 1.4}{3.65}[/tex](380 0.85 - 22 1.4) / 3.65

             m_{maximum} = 80 kg

we can see that the maximum mass that the board supports without turning is greater than the mass of man

             m_{maximum}> m

consequently it is safe to stand at the end of the table


Related Questions

What is the index of refraction of a refractive medium if the angle of incidence in air is 40 degrees and the angle of refraction is 29 degrees?

Answers

N= 1.33
Explanation: (1) sin 40 degrees = n(sin 20 degrees)

The index of refraction is 1.33.

To find the answer, we need to know about index of refraction.

What is index of refraction?

The indication of the light bending ability of a medium is the refractive index of that medium.It determines how much the path of light is bent or refracted.It's a dimensionless number.

What is the mathematical expression of refractive index?

Mathematically, the refractive index(n) is

n= sin∅₁ / sin∅₂

where, ∅₁= angle of incident

             ∅₂= angle of refraction

What is the refractive index,  if the angle of incidence in air is 40 degrees and the angle of refraction is 29 degrees?

n= sin(40) /sin(24) = 1.33

Thus, we can conclude that the index of refraction is 1.33.

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Which of the following is true of the deep
water layer of the ocean?
A. warmest and least dense of the ocean layers
B. experiences a rapid decrease in temperature
C. is warm in the summer and cold in the winter
D. cold all year round

Answers

The answer is D. :>

Medical devices implanted inside the body are often powered using transcutaneous energy transfer (TET), a type of wireless charging using a pair of closely spaced coils. And emf is generated around a coil inside the body by varying the current through a nearby coil outside the body, producing a changing magnetic flux. Calculate the average induced emf, of each 10-turn coil has a radius of 1.50 cm and the current in the external coil varies from its maximum value of 10.0 A to zero in 6.25 x10-6s.

Answers

Answer:

[tex]0.475\ \text{V}[/tex]

Explanation:

n = Number of turns = 10

r = Radius = 1.5 cm

I = Current = 10 A

t = Time = [tex]6.25\times 10^{-6}\ \text{s}[/tex]

[tex]\mu_0[/tex] = Vacuum permeability = [tex]4\pi\times 10^{-7}\ \text{H/m}[/tex]

Magnetic field is given by

[tex]B=\dfrac{\mu_0I}{2r}\\\Rightarrow B=\dfrac{4\pi 10^{-7}\times 10}{2\times 1.5\times 10^{-2}}\\\Rightarrow B=0.00042\ \text{T}[/tex]

EMF is given by

[tex]\varepsilon=\dfrac{nBA}{t}\\\Rightarrow \varepsilon=\dfrac{10\times 0.00042\times \pi (1.5\times 10^{-2})^2}{6.25\times 10^{-6}}\\\Rightarrow \varepsilon=0.475\ \text{V}[/tex]

The average induced emf is [tex]0.475\ \text{V}[/tex].

Coherent light with wavelength of 580 nm passes through two very narrow slits, and the interference pattern is observed on a screen a distance of 3.00 m from the slits. The first-order bright fringe is at 4.81 mm from the center of the central bright fringe. For what wavelength of light will the first-order dark fringe be observed at this same point on the screen?

Answers

Answer:

the required wavelength is 1.15815 μm

Explanation:

Given the data in the question;

The position of bright fringes [tex]y_m[/tex] on screen in double slit experiment is expressed as follows;

[tex]y_m[/tex] = mλD / d

solving for d, we substitute 1 for m

y₁ = (1)λD / d

d = λD / y₁

given that λ = 580 nm = 5.8 × 10⁻⁷ m,  D = 3.00 m and y₁= y₀ = 4.81 mm = 0.00481 m

so we substitute

d = λD / y₁

d = ( 5.8 × 10⁻⁷ m × 3.00 m ) / 0.00481 m

d = 0.00000174 m² / 0.00481 m

d = 3.6117 × 10⁻⁴ m

Now, position of dark fringe  [tex]y_m[/tex] on screen in double slit experiment is expressed as;

[tex]y_m[/tex] = ( m + 1/2 )λD / d

we substitute 0 for m

y₀ = ( 0 + 1/2 )λD / d

y₀ = λD / 2d

2y₀d = λD

λ =  2y₀d  / D

we substitute

λ =  ( 2(0.00481 m) ( 3.6117 × 10⁻⁴ m) )  / 3.0 m

λ = 1.15815 × 10⁻⁶ m

λ = 1.15815 μm

Therefore, the required wavelength is 1.15815 μm

A wheel has an angular speed of 32 rev/s when it experiences a constant angular acceleration of 65 rev/s2 which causes it to spin FASTER. During this time the wheel completes 92 rev. Determine how long the wheel was experiencing this angular acceleration and how fast the wheel was spinning at the end of this period. Assume that the wheel doesn't change the direction of its spin.

Answers

Answer:

ωf = 113.95 rev/s

t = 1.26 s

Explanation:

We can use the third equation of motion to find out the final spinning speed of the wheel:

[tex]2\alpha \theta = \omega_f^2 -\omega_i^2\\[/tex]

where,

α = angular acceleration = 65 rev/s²

θ = No. of revolutions completed = 92 rev

ωf = final angular speed = ?

ωi = initial angular speed = 32 rev/s

Therefore,

[tex](2)(65\ rev/s^2)(92\ rev) = \omega_f^2 - (32\ rev/s)^2\\\omega_f^2 = 11960\ rev^2/s^2 + 1024\ rev^2/s^2\\\omega_f = \sqrt{12984\ rev^2/s^2}[/tex]

ωf = 113.95 rev/s

Now, for the time we can use the first equation of motion:

[tex]\omega_f = \omega_i +\alpha t\\113.95\ rev/s - 32\ rev/s = (65\ rev/s^2)t\\t = \frac{81.95\ rev/s}{65\ rev/s^2}\\\\[/tex]

t = 1.26 s

This force will cause the path of the particle to curve. Therefore, at a later time, the direction of the force will ____________. This force will cause the path of the particle to curve. Therefore, at a later time, the direction of the force will ____________. have a component along the direction of motion remain perpendicular to the direction of motion have a component against the direction of motion first have a component along the direction of motion; then against it; then along it; etc.

Answers

Answer:

have a component along the direction of motion that remains perpendicular to the direction of motion

Explanation:

In this exercise you are asked to enter which sentence is correct, let's start by writing Newton's second law.

circular movement

          F = m a

          a = v² / r

          F = m v²/R

where the force is perpendicular to the velocity, all the force is used to change the direction of the velocity

in linear motion

         F = m a

where the force is parallel to the acceleration of the body, the total force is used to change the modulus of the velocity

the correct answer is: have a component along the direction of motion that remains perpendicular to the direction of motion

Is this right or they wrong definitions which ones are the right ones someone !!!!!

Answers

Answer:

They are right.

Explanation:

Answer:

Mechanical Energy : KE + PE

Conversion : "When energy transfers from one form to another"

Potential Energy: the energy possessed by a body by virtue of its position relative to others , stresses within itself, electric charge , and other factors .'

Kinetic Energy: energy of an object in motion

Law of conservation of energy: KE+PE+friction=KE

Explanation:

First of all mechanical energy is kinetic energy plus potential energy (it is the energy of movement) So:

Mechanical Energy : KE + PE

Conversion is when energy converts or becomes a different form. So:

Conversion : "When energy transfers from one form to another"

Potential energy is stored energy, in Physics I or AP Physics I, it is often due to it being at a height, but batteries, foods, etc. are also example of it, so:

Potential Energy: the energy possessed by a body by virtue of its position relative to others , stresses within itself, electric charge , and other factors .'

Kinetic energy is for objects in motion so you got it right!

Kinetic Energy: energy of an object in motion

The law of conservation of energy means there is the same amount of energy before, as there is after, so when you see an equation with energy on both sides, it is usually this. Also, this is the last question left, so this has to be the answer.

Law of conservation of energy: KE+PE+friction=KE

Two identical speakers are set some distance apart in a large open field. Both are producing sound, in unison, with a wavelength of 4 m. An observer wandering around the field notices that the sound is surprisingly loud at certain locations and unusually quiet at others. The observer concludes that this is the effect of interference between the two sources of sound waves. For each location, indicate which sort of interference would occur at that point.

Answers

Answer:

Constructive interference occurs at the surprisingly loud locations and destructive interference occurs at the unusually quiet locations.

Explanation:

This is because, constructive interference tends to combine the effects of the wave when they are in phase (that is, moving in the same direction), which thus amplifies the effect and produces surprisingly loud sounds at those locations, while destructive interference occurs when the waves are out of phase with each other(that is, move in opposite directions) and thus, their effects tend to cancel out thus producing locations of unusually quiet sounds.

What do you mean by physics?

Answers

Answer:

Explanation:

Physics is the branch of science that studies the natural world and its rules and orders. It is one of the oldest sciences as ancient people study the stars and astronomy is considered part of Physics.

A light bulb has a resistance of 360 . What is the current in the bulb when it has a potential difference of 120 V across it? 0.33 A 3 A 480 A 43,200 A

Answers

Answer:

I=R×V

360×120 V

=43,200 A

Answer:

A.)0.33 A

Explanation:

i just took the quiz 2021

3.
Two Cars, A and B, (starting, at the same time, from the same point) are moving
with average speeds of 40 km/h and 50 km/h, respectively, in the same direction.
Find how far will Car B be from Car A after 3 hours.

Answers

Answer:

car B will be 30 Km ahead of car A.

Explanation:

We'll begin by calculating the distance travelled by each car. This is illustrated below:

For car A:

Speed = 40 km/h

Time = 3 hours

Distance =?

Speed = distance / time

40 = distance / 3

Cross multiply

Distance = 40 × 3

Distance = 120 Km

For car B:

Speed = 50 km/h

Time = 3 hours

Distance =?

Speed = distance / time

50 = distance / 3

Cross multiply

Distance = 50 × 3

Distance = 150 Km

Finally, we shall determine the distance between car B an car A. This can be obtained as follow:

Distance travelled by car B (D₆) = 150 Km

Distance travelled by car A (Dₐ) = 120 Km

Distance apart =?

Distance apart = D₆ – Dₐ

Distance apart = 150 – 120

Distance apart = 30 Km

Therefore, car B will be 30 Km ahead of car A.

What is a gravitational force?

Answers

Answer:

It is the force that pulls down an object on the air

Answer: a downward pull on any object

Explanation:

Which of the following is NOT a natural
source of pollution?
A. erupting volcanoes
B. dust storms
C. construction
D. forest fires

Answers

Answer:

hi

Explanation:

answer is C

have a nice day

The answer is c.Construction as it is performed by human activity

sound wave of a wave length of 0.56 meters if its speed is 280 m/s what is the wave frequency

Answers

Answer:

500 Hz

Explanation:

Formula for finding wave frequency is,

f = c/λ

f = frequency

c = speed (m/s)

λ = wave length (m)

f = c/λ

f = 280/0.56

f = 500

∴ wave frequency is 500 Hz

Brian Lara is a cricketer playing in the field on the second day of a cricket test-match. He exerts a forward force on the 0.145kg cricket ball, as he catches it, to bring it to rest from a speed of 38.2m/s. During the process, his hand recoils a distance of 0.135m. Determine the acceleration of the ball and the force which is applied to it by Brian Lara.

Answers

Answer:

a = -3984.6 m/s²

F = 577.76 N

Explanation:

The acceleration of the ball can be calculated by using the third equation of motion:

[tex]2as = v_f^2 - v_i^2\\[/tex]

where,

a = acceleration of ball = ?

s = distance covered = recoil distance = 0.135 m

vf = final speed = 0 m/s

vi = initial speed = 38.2 m/s

Therefore,

[tex]2(0.135\ m)a = (0\ m/s)^2-(38.2\ m/s)^2\\[/tex]

a = -3984.6 m/s²

here negative sign shows deceleration.

Now, for the force applied by Brian Lara will be equal in magnitude but opposite in direction of the force required to stop the ball:

[tex]F = -ma\\F = -(0.145\ kg)(-3984.6\ m/s^2)\\[/tex]

F = 577.76 N

What my fav food for 20 points if you know it!?

Answers

Answer:

pizza

Explanation:

Answer:

sea food???

Explanation:

Which of the following is NOT part of the grain group?

Answers

Answer:

Any food made from wheat, rice, oats, cornmeal, barley, or another cereal grain is a grain product. Anything else is not

Explanation:

what must be the mass of a rock if a boy applies a 64N force and causes it to accelerate at 4.51m/s2

Answers

first of all the formula of force is F=ma,so we are searching for m,so we can divide a on both sides F/a=m, after this substitute the values given above 64N/4.51=14.2°Kg

scholastic science world
CHECK FOR UNDERSTANDING: VIDEO GAME TYCOONS

Answers

I dont see it ;-; REEEEEEEE

A student wearing in-line skates pushes against a brick wall. why does the student move away from the wall ?

1. Because the forces acting on the student are balanced

2. Because the forces acting on the student are creating a net force

3. Because gravity is less than the student's push on the wall

4. Because the friction between the skates and the pavement is greater than the student's push on the wall

Answers

Answer:

Because the forces acting on the student are creating a net force.

Explanation:

I took the test and that was the answer

Answer:

Because the forces acting on the student are creating a net force

Explanation:

A 0.545-kg ball is hung vertically from a spring. The spring stretches by 3.56 cm from its natural length when the ball is hanging at equilibrium. A child comes along and pulls the ball down an additional 5cm, then lets go. How long (in seconds) will it take the ball to swing up and down exactly 4 times, making 4 complete oscillations before again hitting its lowest position

Answers

Answer:

t = 9.52 s

Explanation:

This is an oscillatory motion exercise, in which the angular velocity is

         w = [tex]\sqrt{ \frac{k}{m} }[/tex]

Let's use hooke's law to find the spring constant, let's write the equilibrium equation

        F_e - W = 0

        F_e = W

        k x = m g

        k = [tex]\frac{m g}{x}[/tex]

        k = 0.545 9.8 /0.0356

        k = 150 N / m

now the angular velocity is related to the period

          W = 2π / T

we substitute

          4π² T² = k /m

          T = 4pi² [tex]\sqrt{ \frac{m}{k} }[/tex]

we substitute

           T = 4 pi² [tex]\sqrt{ \frac{0.545}{150} }[/tex]

            T = 2.38 s

therefore for the spring to oscillate 4 complete periods the time is

            t = 4 T

            t = 4 2.38

            t = 9.52 s

what happens during subduction

Answers

Answer:

Subduction , Latin for "carried under," is a term used for a specific type of plate interaction. It happens when one lithospheric plate meets another—that is, in convergent zones —and the denser plate sinks down into the mantle.

Please help & actually answer thank you :)

Answers

Answer:

0.5x35=17.5

Explanation:

You throw 0.5 kg the ball leaves your hand with

A speed of 35

Which of the following is an example of an electromagnetic wave?

a radio wave

a water wave

the oscillation of a spring

sound waves

Answers

Radio waves is the correct answer

What happens when a neutral atom gains an electrons?

Answers

it will become a ion , if it gains a negative electron it becomes a negative ion

Answer:

The neutral atom becomes an anion.

Explanation:

When a neutral atom gains an electron (e−), the number of protons (p+) in the nucleus remains the same, resulting in the atom becoming an anion (an ion with a net negative charge).

HELP 30 POINTS
The picture above shows a cross section of the Earth’s interior including both oceanic crust and continental crust. Along the seafloor, there are mid–ocean ridges where magma rises to the surface and creates new crust. There are also areas where crust is recycled as oceanic crust goes below continental crust. What type of boundary would occur at a mid-ocean ridge?

Answers

Mid-ocean ridges happen along divergent plate boundaries, where new ocean floor is created as the Earth’s tectonic plates spread apart. As the plates separate, molten rock rises to the seafloor, producing large volcanic eruptions of basalt.

what do solar winds and the earths magnetic field create

Answers

Answer:

bc earth rotates

3==D---------- :P3==D---------- :P3==D---------- :P3==D---------- :P3==D---------- :P3==D---------- :P3==D---------- :P3==D---------- :P3==D---------- :P3==D---------- :P3==D---------- :P3==D---------- :P3==D---------- :P3==D---------- :P3==D---------- :P3==D---------- :P3==D---------- :P3==D---------- :P3==D---------- :P3==D---------- :P3==D---------- :P3==D---------- :P3==D---------- :P3==D---------- :P3==D---------- :P3==D---------- :P

Explanation:

Answer:

The interaction between the solar wind and Earth's magnetic field, and the influence of the underlying atmosphere and ionosphere, creates various regions of fields, plasmas, and currents inside the magnetosphere such as the plasmasphere, the ring current, and radiation belts.

Explanation:

How far could you walk backwards in one hour? Use your speed from the 10m test to calculate the answer. Show your work or you will not receive credit.

Answers

Answer: Sweetheart i'm not walking backward for an hour for your little assignment

Explanation: Do it yourself lazy! Have a great day!

PLEASE HELP! I'LL GIVE BRAINLEST​

Answers

Answer:

In this conversation the Neil astronaut is right

What is characteristic of a good insulator?
A. Electrons are usually not moving at all.
B. Electrons are free to move around.
C. Electrons are semi-free to move around.
D. Electrons are tightly bound to the nuclei.

Answers

Answer:

D. Electrons are tightly bound to the nuclei.

Explanation:

In an insulator, the electrons of the outer most shell are bound with a very high electrostatic forces coming from the nucleus of each atom so electrons cannot flow around all atoms making up the material as in a conductor.

The characteristic of a good insulator is Electrons are tightly bound to the nuclei. (option d)

In a good insulator, electrons are tightly bound to the nuclei of their atoms. This means that they are not free to move around within the material, unlike conductors where electrons are relatively loosely bound and can move freely. Due to this strong binding, electrons in insulating materials cannot carry an electric charge or energy easily from one atom to another.

When an electric field is applied to an insulator, the electrons may experience a small displacement within their respective atoms, but they generally do not move from one atom to another or flow through the material like they would in a conductor. As a result, insulators prevent the flow of electric current and are used to isolate or protect conductive elements from accidental contact.

So, the correct answer is D. Electrons are tightly bound to the nuclei.

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