Two supports, made of the same material and initially of equal length, are 2.0 m apart. A stiff board with a length of 4.0 m and a mass of 10 kg is placed on the supports, with one support at the left end and the other at the midpoint. A block is placed on the board a distance of 0.50 m from left end. As a result the board is horizontal (that is, the downward force on each support is the same). The mass of the block is:

Answers

Answer 1

Answer:

20 kg

Explanation:

Assuming that the board remains horizontal with the unknown mass on it, then F = kx

If we add the vertical forces to zero, we have something like this

2F - (M + 10)g = 0

2F = (M + 10)g, next, divide both sides by 2

F = (M + 10)g/2

Since we were able to sum the moments at the right end of the board to zero, we then proceed to find the unknown mass M

To start, we say, Let the clockwise moment is positive, and so

F * 4 + F * 2 - Mg * 3.5 - 10 * g * 2 = 0

4F + 2F - 3.5Mg - 10 * 2 * g = 0

6F - 3.5Mg - 10 * 2 * g = 0,

Remember from above, we say that

F = M + 10)g/2, now, all we do is substitute it inside this equation

6 * (M + 10)g/2 - 3.5Mg - 10 * 2 * g = 0

3 * (M + 10)g - 3.5Mg - 10 * g * 2 = 0, divide all sides by g(so as to eliminate it)

3 (M + 10) - 3.5M - 10 * 2= 0

3M + 30 - 3.5M - 20 = 0

-0.5M + 10 = 0

0.5M = 10

M = 10/0.5

M = 20 kg

Answer 2

The mass of the block that was placed on the board is; M = 20 kg

Since the two supports are the same, then it means their forces will be the same.

Thus;

Force at left support = F

Force at right support = F

Now, we are told that a block of unknown mass is placed on the stiff board. This means that the sum of the weight of the board and and the block on it will be; (M + 10)g

where M is the mass of the block.

Now, from equilibrium we know that sum of upward forces is equal to sum of downward forces. Thus;

F + F = (M + 10)g

Thus;

2F = (M + 10)g

F = ¹/₂(M + 10)g

Now, taking moments about the right end gives;

(F × 4) + (F × 2) - (M × 3.5)g - (10 × 2)g = 0

6F - 3.5Mg - 20g = 0

Put ¹/₂(M + 10)g for F to get;

6(¹/₂(M + 10)g) - 3.5Mg - 20g = 0

Divide through by g to get;

3(M + 10) - 3.5M = 20

3M + 30 - 3.5M = 20

3.5M - 3M = 30 - 20

0.5M = 10

M = 10/0.5

M = 20 kg

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Related Questions

11.50 kg object has the given and acceleration components. =(0.35ms2)+(0.73ms3) =(11.5ms2)−(0.75ms3)

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I am not sure. Can you help me with my question?

Calculate the potential difference of a wire of 10 ohm , through which 5 A of current is flowing .

2 V

50 V

0.2 V

0.5 V​

Answers

Resistance= Potential Difference/Current
10 Ohm= PD/ 5A
PD= 10 Ohm × 5A
PD=50
Therefore, Potential Difference is B. 50 V

A car is traveling 16 m/s East. If the car then speeds up at a constant acceleration, what is the direction of the car’s acceleration?

Answers

The direction is east since its constant

difference between boiling point and freezing point​

Answers

Laurie the vapor pressure of a substance has an advice effect and boiling point the boiling point goes up of pressure as the temperature at which the short salad in it with the liquid at the freezing point the rate at which the solid months is equal to the rate at which the liquid freezers

During a relay race, runner A runs a certain distance due north and then hands off the baton to runner B, who runs for the same distance in a direction south of east. The two displacement vectors A and B can be added together to give a resultant vector R. Which drawing correctly shows the resultant vector?

Answers

Answer:

d) 4

Explanation:

The image attached shows the options.

The resultant vector is the resultant of two or more vectors. The resultant vector is gotten by adding the sum of the displacement of the vectors together (that is the sum of all the individual vectors).

From the question, since runner A runs north and runner B runs east the resultant vector would be the sum of the displacement of vectors A and B. Also, the direction of the vector would be the north east starting from the beginning of vector A to end of vector B. The correct option is d) 4

The driver of a truck has an acceleration of 0.3 g as the truck passes over the top of a hump in the road at a constant speed. The radius of curvature of the road at the top of the road is 98 m, and the center of mass G of the driver, who can be considered a particle, is 2 m above the road. What is the speed of the truck

Answers

Answer:

17.115m/s

Explanation:

The formula that will be used to calculate the speed of the truck is expressed as shown:

v = √ar

a is the acceleration of the truck

r is the radius of curvature of the road at the top of the road plus centre of mass G who can be considered a particle, is 2 m

v = √a(R+G)

Given parameters

a = 0.3g (g is the acceleration due to gravity)

R = 98m

G = 2m

Substituting the values into the formula:

v = √0.3(9.81){98+2}

v = √0.3×9.81×100

v = √294.3

v = 17.155m/s

Hence the speed of the truck is 17.155m/s

EXPLAINING ISSUES How did Rome’s status as a site of encounter change the lives of Roman citizen

Answers

Answer:

Below, the definition including its position of Roman people is clarified.

Explanation:

Conflicts began to rise in most of the other societies surrounding Rome, as Rome gained property mostly in the peninsula. They were requesting an improvement or change in one's position from these recently subjugated people. Though without the election, they might intermarry among Romans, negotiate agreements and also have freedom of movement brooking sine suffrage as well as citizenship, individuals also requested more.

wire 1 and 2 are made of the same metal. wire 2 has twice the length and diameter of the of wire 1.what is the ratio R2/R1 of the resistance of two wire ?​

Answers

Since the wires are made up of the same material, the resistivities will be the same.

Impulse is the______of the force and time of contact

Answers

Answer:

Product

Explanation:

Impulse is defined as the average force acting on an object times the time the force acts:

Impulse = F · Δt

a supposition or proposed explanation made on the basis of limited evidence as a starting point for further investigation.

Answers

That's a good, simple description of a "hypothesis".

Another way to describe it is "an educated guess".

Once you have it in words, it's time to start checking it out, with experiments that can show whether it's true or not.  

If your experiments seem to show that your hypothesis seems to be true, that doesn't 'prove' it, but you can start calling your hypothesis a "theory".  

(It's possible that you may never be able to 'prove' it.  It may remain a theory forever. Like gravity, germs, atoms, and relativity.  Thousands of successful experiments don't 'prove' a theory, but it can be trashed by one good, valid experiment to show that it's false.)

A boy on a roof throws one ball downward and an identical ball upward. The ball thrown downward hits the ground with 100 J of kinetic energy. If both balls are thrown at the same speed and there is no air friction, what is the kinetic energy of the second just before it hits the ground

Answers

Answer:

It will be Less than 100J

Explanation:

Because the second ball has both kinetic and potential energy so just before it hits the ground the kinetic energy will be total energy-potential energywhich will be less than 100J

A jetliner, traveling northward, is landing with a speed of 71.9 m/s. Once the jet touches down, it has 675 m of runway in which to reduce its speed to 11.3 m/s. Compute the average acceleration (magnitude and direction) of the plane during landing (take the direction of the plane's motion as positive).

Answers

Answer:

The value is  [tex]a =  -3.7 \  m/s^2 [/tex]

Explanation:

From the question we are told that

   The  landing speed is  [tex]u =  71.9 \  m/s[/tex]

   The  distance traveled is  [tex]d =  675 \  m[/tex]

    The velocity it is reduced to is  [tex]v  =  11.3 \  m/s[/tex]

   

Generally the average acceleration is mathematically represented as

      [tex]a =  \frac{ v^2  -  u^2 }{ 2 * d }[/tex]

=>  [tex]a =  \frac{ 11.3^2 - 71.9^2 }{ 2 * 675 }[/tex]

=>   [tex]a =  -3.7 \  m/s^2 [/tex]

A 30-microfarad capacitor is charged to 90 v and then connected across an initially un charged capacitor of unknown capacitanc c .if the final potintial difference across the 30- microfarad capacitor is 20 v sitemin c

Answers

Answer:

The value  is   [tex]  C_u   =   5 *10^{-6} F[/tex]

Explanation:

From the question we are told that

   The voltage of the capacitor is  [tex]V  =  90 \  V[/tex]

   The  capacitance of the capacitor is  [tex]C  =  30 \ \mu F =  30 *10^{-6} \  F[/tex]

   The  final voltage is  [tex]V_a =  20 \  V[/tex]

Since the capacitors are connected in parallel we have that

      [tex]Q_u  =  Q'_u  +  Q[/tex]

Where  [tex]Q_u[/tex] is the charge of the known capacitor before it is connected to the known capacitor

     [tex]Q_u' [/tex] is the charge of the known capacitor after it is connected

       [tex]Q  [/tex] is the charge of the unknown capacitor

Also the potential across the two capacitors will be the same (except for a loss due heat (it been converted to heat ))

So

            [tex]CV  =  CV_a +  C_u *  V_a[/tex]

=>          [tex]  C_u *  V_a   =  CV - CV_a [/tex]

=>          [tex]  C_u   =   \frac{CV - CV_a }{ V_a } [/tex]

=>          [tex]  C_u   =   \frac{ [30*10^{-6} *90] - [30*10^{-6} * 20] }{ 20 } [/tex]

=>        [tex]  C_u   =   5 *10^{-6} F[/tex]

A soda has mass of 1500 g and a density of 2.9 g/ml . What is the volume?

Answers

D= 2.9 g/ml
M= 1500 g
V= .52 L

The density of the substance is its mass divided by volume. Thus, the volume of 1500 g soda with a density of 2.9 g/ml is 517.2 g/ml.

What is density?

Density of a substance is the measure of its mass per unit volume. The density of a substance depends on its bond type, temperature and pressure as well.

The volume of a substance is the space occupied by its particles. The volume of the substance is the mass divided by density.

Volume is generally expressed in units of liters or milliliters.

Given that, mass of soda = 1500 g

density = 2.9 g/ml

volume = mass/ density

v  =  1500 g/ 2.9  g/ml = 517.2 ml.

Therefore, the volume of soda is 517.2 ml.

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A hot air balloon is descending with a velocity of 2.0 m/s straight down. At a height of 6m, a champagne bottle is opened to celebrate a successful flight, expelling the cork horizontally with a velocity of 5.0 m/s. a. What is the initial velocity (magnitude and direction) of the cork, as seen by an observer on the ground? b. What are the horizontal and vertical components of the initial velocity? c. How long is the cork in the air? d. How far away from the balloon does it land?

Answers

Answer:

a

   [tex]v  =  5.39 \  m/s[/tex]

b

Horizontal component

     [tex]v_x  =  5.00 \  m/s[/tex]

vertical component

     [tex]v_y  =  - 2.0 \  m/s[/tex]

c

     [tex]t =  0.921 \  s[/tex]

d

[tex]d = 4.605 \  m [/tex]

Explanation:

Generally from the question we can deduce that he initial velocity of the cork, as seen by an observer on the ground in terms of the x  unit vector is  

     [tex]v_x  =  5.00 \  m/s[/tex] due to the fact that the cork is moving horizontally

Generally from the question we can deduce that the vertical and horizontal  components of the initial velocity is  

       [tex]v_y  =  - 2.0 \  m/s[/tex] due to the fact that the balloon is moving downward which is the negative which will also cause the cork to move vertically with the balloon speed

Generally the  initial velocity (magnitude and direction) of the cork, as seen by an observer on the ground is mathematically represented as

       [tex]v  =  \sqrt{ v^2 _x  + v^2 _y  }[/tex]

       [tex]v  =  \sqrt{ 5^2  + (-2)^2 _y  }[/tex]

        [tex]v  =  5.39 \  m/s[/tex]

Generally the  initial direction of motion as seen by the same observer is mathematically represented as

    [tex]\theta =  tan^{-1}[\frac{2}{5} ][/tex]

    [tex]\theta  =  21.80^o[/tex]

Generally the time taken by the cork in the air before landing is mathematically represented as

       [tex]D  =  ut  + \frac{1}{2} g t^2[/tex]

So  D =  6 \  m from the question

     g =  9.8 \  m/s^2

     u  =  [tex]v_y[/tex] =  2 m/s  this because we are considering the  vertical motion

So

     [tex]6  =   2 t  + \frac{1}{2} *  9.8*  t^2[/tex]

       [tex]6  =   2 t  + 4.9  t^2[/tex]

Solving using quadratic formula w have that

      [tex]t =  0.921 \  s[/tex]

Generally the distance of the cork from the balloon is mathematically represented as

     [tex]d = v_x  *  t[/tex]

    [tex]d = 5  * 0.921 [/tex]

      [tex]d = 4.605 \  m [/tex]

   

     

       

A 200g mass is attached to a spring, of spring constant, k. The spring is compressed, 15cm from its equilibrium value. When released, the mass reaches a speed of 5m/s. What is the spring constant (in N/m)?

Answers

Answer:

The spring constant is 222.2 N/m

Explanation:

Given;

mass of the spring, m = 200 g = 0.2 kg

extension of the spring, x = 15 cm = 0.15 m

speed of the mass, v = 5 m/s

spring constant, k = ?

Apply law of conservation of energy;

¹/₂kx² = ¹/₂mv²

k = mv² / x²

k = (0.2 x 5²) / (0.15²)

k = 222.2 N/m

Therefore, the spring constant is 222.2 N/m

Two mechanical waves intersect and produce the straight line seen here. What is the result of this intersection called?

Answers

Answer:constructive interfrence

Explanation:

Mass of mercury = 57 g Volume of mercury = 4.2 mL

Answers

24 beautiful women and women who have a good relationship and you can get a good laugh and

The 45-g Wood Thrush migrates every spring from Central America to the United States to breed. The bird leaves its winter
home in Belize and travels 1422 km across the Gulf of Mexico to Louisiana. It then flies an additional 1343 km to reach
Virginia, where it spends the summer. The trip takes approximately 171 hours, flying mostly at night.
What is the average speed of the Wood Thrush?

Answers

Answer:

v = 16.16 km/h

Explanation:

Distance covered by Wood Thrush is 1422 km across the Gulf of Mexico to Louisiana + 1343 km to reach  Virginia, where it spends the summer.

d = 1422 km + 1343 km

d = 2765 km

The trip takes approximately 171 hours, flying mostly at night, t = 171 hours

We need to find the average speed of the Wood Thrush. It can be given by :

[tex]v=\dfrac{d}{t}\\\\v=\dfrac{2765\ km}{171\ h}\\\\v=16.16\ km/h[/tex]

So, the average speed of the Wood Thrush is 16.16 km/h.

A massive block is being pulled along a horizontal frictionless surface by a constant horizontal force. The block must be __________. View Available Hint(s) A massive block is being pulled along a horizontal frictionless surface by a constant horizontal force. The block must be __________. continuously changing direction moving at constant velocity moving with a constant nonzero acceleration moving with continuously increasing acceleration

Answers

Answer:

The body must be moving with a constant non zero acceleration.

Explanation:

Force produces acceleration on any mass it is applied on. The acceleration produced depends on the magnitude and direction of the force. For this block being dragged by a constant horizontal force, The body will undergo a constant non-zero acceleration that will steadily increase its velocity along the direction of the force.

What trend does the reactivity of nonmetals show in a periodic table? random changes without any trends on the periodic table changes according to trends on the periodic table increases from left to right across the periodic table decreases from left to right across the periodic table

Answers

Answer:

C) increases from left to right across the periodic table

Explanation:

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The trend of the reactivity of non metals in the periodic table is that it increases from left to right across the periodic table.

The periodic table is composed of metals on the left hand side and nonmetals on the right hand side.

As such, nonmetallic property increases from left to right across a period and so does the reactivity of nonmetals.

This implies that as we move from left to right across a period, nonmetallic elements become more reactive.

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Children are told to avoid standing too close to a rapidly moving train because they might get sucked under it. Is this possible? Explain.

Answers

Answer:

no its not like the undertow in the ocean

Explanation:

Answer:

Yes

Explanation:

This is possible due to Bernoulli's principle.

A tow truck is using a cable to pull the classic car up a 15o hill. If the classic car weighs 4000 lbs and the cable has a diameter of 3/4 inch, find the stress in the cable when the truck comes to a stop while on the hill. Ignore friction between the car and the pavement

Answers

Answer:

the stress in the cable at the time when the truck is stop is 2,344.57  lb/m^2

Explanation:

The computation of the stress in the cable when the truck comes to a stop is shown below:

We used the following formula

[tex]T = mg\times sin\theta\\\\= 4,000 \times sin15^{\circ}[/tex]

= 1,035.28

Now the stress in the cable is

Before calculating it first determined the area which is

[tex]Area = \frac{\pi}{4}\times (\frac{3}{4})^2 \\\\= \frac{9\pi}{64}[/tex]

So, the stress is

[tex]= \frac{T}{area}\\\\ = \frac{1,035.28}{\frac{9\pi}{64} }[/tex]

= 2,344.57  lb/m^2

Hence, the stress in the cable at the time when the truck is stop is 2,344.57  lb/m^2

A car starts 20 miles north of town then travel for 40 minutes until it is 100 miles north of town. What is the cars velocity over this time frame?

Answers

The answer: 2 miles per minute

Which statement is TRUE?
A) Energy can be created or destroyed.
B) Electrical energy is created from other forms of energy.
C) Energy in a battery makes new energy called electrical energy.
D) Stored energy in a battery can be transformed into electrical energy.

Answers

The answer is B I know this because I’m Asian

How much work is done on a small car of a 1000 N force is exerted to move it 75 m to the side of the road?

Answers

Answer:

7500j

Explanation:

Work :

W = Fd (work = force x distance)

Force :

F = W/d

Distance :

d = W/F

What is the definition of Acceleration? In science?

Answers

Answer:

The definition of acceleration is is a vector quantity that is defined as the rate at which an object changes its velocity.

Explanation:

Answer:

DescriptionIn mechanics, acceleration is the rate of change of the velocity of an object with respect to time. Accelerations are vector quantities. The orientation of an object's acceleration is given by the orientation of the net force acting on that object.

Explanation:

7.9x10^9 km is equal to?

Answers

Explanation:

7.9x10^9 km is equal to

=7900000000km

Please mark it as brainliast

g Two tiny identical spheres of mass m = 66.7 g carry identical positive charge q. The charges hang from identical massless threads of length L = 84.8 cm attached to a ceiling at the same point. The spheres repel, and the angle between the threads is θ = 33o. Find q, the charge on each sphere, in μC.

Answers

Answer:

Explanation:

a

The angle each thread is making with the vertex = 16.5 degree

weight acting downwards = 66.7 x 10⁻³ x 9.8 N .

distance between two charges = 2 x 84.8 x 10⁻² sin 33/2

= .48 m

repulsive force between the two charges

= 9 x 10⁹ x q² / .48²

F = 39 x 10⁹ q²

Now, the tension in the thread be T

T cos 16.5 = mg

T sin 16.5 = F

dividing

tan 16.5 = F / mg = 39 x 10⁹ x q² / 66.7 x 10⁻³ x 9.8

.296 x  66.7 x 10⁻³ x 9.8 = 39 x 10⁹ x q²

q² = 4.96 x 10⁻¹²

q = 2.23 x 10⁻⁶ C

= 2.23 μC

What is the field outside the capacitor plates in a parallel capacitor?

Answers

Answer:

Zero

Explanation:

If using an ideal parallel plate capacitor, the electric field outside should be nearly zero.

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