Three books are at rest, in equilibrium, on a horizontal table as
shown. The weight of each book, which is equal to the force
gravity exerts in the downward direction, is given. What is the
net force on the middle book?​

Answer:

D. transparent and translucent materials

Explanation:

OPAQUE MATERIALS:

Opaque Materials are those materials that absorb all the light and do not allow the light to pass through them.

TRANSLUCENT MATERIALS:

Translucent materials are those materials, that absorb a portion of light, allowing the light to partially pass through them.

TRANSPARENT MATERIALS:

Transparent materials are those materials that do not absorb the light and allow the light to completely pass through them.

Therefore, the correct option is:

D. transparent and translucent materials

Answer:

A farmer with a field of solar panels.

Explanation:

The closest to a locally sources energy would have been

A coal mine located in their county.

But coal as an energy source is not environmentally friendly due to carbon emission, and should not be what the group should advocate for.

The best bet for them is

A farmer with a field of solar panels.

As solar panels are a source of green energy and green energy is what the environmental group should often and always advocate for

Answer:

a) 8.89 s

b) 50.6 m/s

c) 25.3 m/s

Explanation:

d = 225 m

v₀ = 0 m/s

a = (-3.5i + 4.5j) m/s²

First, find the magnitude of the acceleration.

a = √((-3.5)² + (4.5)²) m/s²

a = 5.7 m/s²

a) Find t

Δx = v₀ t + ½ at²

225 m = (0 m/s) t + ½ (5.7 m/s²) t²

t = 8.89 s

b) Find v

v² = v₀² + 2aΔx

v² = (0 m/s)² + 2 (5.7 m/s²) (225 m)

v = 50.6 m/s

c) Find v_avg

v_avg = Δx / t

v_avg = 225 m / 8.89 s

v_avg = 25.3 m/s

Or, for constant acceleration:

v_avg = (v₀ + v) / 2

v_avg = (0 m/s + 50.6 m/s) / 2

v_avg = 25.3 m/s

Answer:

i) 20-30 kg

Explanation:

The child with the smallest mass range of 20-30 kg will require the smallest force to move his skate board because he/she has a smaller inertia force to overcome. The mass of a body is the measure of the inertia forces of the body. The inertia force makes it difficult for a body at rest to start moving, and a body already in motion to stop moving.

When the children try to move the skateboard, they exert a force that is proportional to the product of their mass and the acceleration with which they start moving. This force must exceed their body's inertia force before they would start moving.

from

F = ma

where F is the force required

m is the mass

a is the acceleration

We can see that for the given mass ranges, the children with the larger mass range will require more force in order to move their skateboard. Consequently, the child with the smallest mass range will require the smallest pushing force to move his skate board.

Answer:

Stopping distance = 40m

Explanation:

Given the following :

Initial speed of vehicle before applying brakes = 72km/hr

Converting km/hr to m/s:

72km/hr = [(72 * 1000)m] / (60 * 60)

72km/hr = 72,000m / 3600s

72km/hr = 20m/s

Deceleration after applying brakes (-a) (negative acceleration) = - 5m/s^2

From the 3rd equation of motion:

v^2 = u^2 + 2as

Where v = final Velocity ; u= Initial Velocity ; a = acceleration and s = distance

Final velocity when the car stops will be 0

Therefore ;

v^2 = u^2 + 2as

0 = 20^2 + 2(-5)(s)

0 = 400 - 10s

10s = 400

s = 400/10

s = 40m

Therefore, the stopping distance of the car = 40 meters

Answer:

c) Albert Einstein,

Explanation:

in his theory of special relativity, determined that the laws of physics are the same for all non-accelerating observers, and he showed that the speed of light within a vacuum is the same no matter the speed at which an observer travels.

hope this helped

-lvr

Answer:

1666.7 ETB (birr)

833.3 ETB (birr)

2083.3 ETB (birr)

Explanation:

The first worker

5000*1/3=1666.7

The second worker

5000*1/6=833.3

The third worker

5000*5/12=2083.3

Hope this helps :) ❤❤❤

Explanation:

It is given that,

The angle of projection is 60 degrees

Initial velocity of the ball is 120 m/s

We need to find the time taken to get to the maximum height and the time of flight.

Time taken to reach the maximum height is given by :

[tex]T=\dfrac{u^2\sin^2\theta}{2g}[/tex]

g is acceleration due to gravity

[tex]T=\dfrac{(120)^2\times \sin^2(60)}{2\times 10}\\\\T=540\ s[/tex]

(ii) Time of flight,

[tex]t=\dfrac{2u\sin\theta}{g}[/tex]

So,

[tex]t=\dfrac{2\times 120\times \sin(60)}{10}\\\\t=20.78\ s[/tex]

Hence, this is the required solution.

Answer:

[tex]\sf Proof \ below[/tex]

Explanation:

We know that acceleration is change in velocity over time.

[tex]\sf a=\frac{\triangle v}{t}[/tex]

[tex]\sf a=\frac{v-u}{t}[/tex]

v is the final velocity and u is the initial velocity.

Solve for v.

Multiply both sides by t.

[tex]\sf at=v-u[/tex]

Add u to both sides.

[tex]\sf at + u=v[/tex]

Answer:

Acceleration = v-u/t  when we flip -u and t to right hand side

then -u changes to plus and denominator t changes to numerator

then then  this equations becomes  v=u+at

Explanation:

explanation

the general form of wave equation is

       y=Asin(kx-wt)

we have

      y=5sin(3x-4t)

hence the angular frequency

     w= 4s^-1

the frequency

  f=w/2 pi

  f=4/2 pi

  f=4/2*3.14

  f=0.64 hz

the period

T=1/f

T=1/0.64

T=1.5625=1.6

the wavelength

k=2 pi/lambda

lambda=2 pi/k

k=3

so

lambda=2*3.14/3

lambda=2.09

if my answer is right then mark me brainlist

Answer:

Hydrogen used in fuel cells has the energy to weight ratio ten times greater than lithium-ion batteries. Consequently, it offers much greater range while being lighter and occupying smaller volumes. It can also be recharged in a few minutes, similarly to gasoline vehicles.

Answer:

1.92 kg of nitrogen.

Explanation:

The following data were obtained from the question:

Heat absorbed (Q) = 384000 J

Note: Heat of vaporisation (ΔHv) of nitrogen = 5600 J/mol

Next, we shall determine the number of mole of nitrogen that absorbed 384000 J.

This is illustrated below:

Q = mol·ΔHv

384000 = mole of N2 x 5600

Divide both side by 5600

Mole of N2 = 384000/5600

Mole of N2 = 68.57 moles

Next, we shall convert 68.57 moles of nitrogen, N2 to grams.

This can be obtained as follow:

Molar mass of N2 = 2 x 14 = 28 g/mol.

Mole of N2 = 68.57 moles.

Mass of N2 =..?

Mole = mass /molar mass

68.57 = mass of N2 /28

Cross multiply

Mass of N2 = 68.57 x 28

Mass of N2 = 1919.96 g

Finally, we shall convert 1919.96 g to kilograms.

This can be achieved as shown below:

1000g = 1 kg

Therefore,

1919.96 g = 1919.96/1000 = 1.92 kg.

Therefore, 1.92 kg of nitrogen were burned off.

Answer:

Explanation:

i cheat on Acellus cause I dont care about school. If i did I would be going to public school... Im never gonna use this info in my life so I dont bother learning it.

Answer:

[tex]g=0.035\ m/s^2[/tex]

Explanation:

Given that,

Mass of Earth, [tex]m=6\times 10^{24}\ kg[/tex]

We need to find the gravitational acceleration of a satellite that is in orbit at a distance of [tex]10^8\ m[/tex] from the center of the Earth.

Radius of earth is 6,371 km

The formula used to find the gravitational acceleration at a distance is given by :

[tex]g=\dfrac{Gm}{R^2}[/tex]

R = r+d

[tex]g=\dfrac{6.67\times 10^{-11}\times 6\times 10^{24}}{(10^8+6371\times 10^3)^2}\\\\g=0.035\ m/s^2[/tex]

So, the gravitational acceleration is [tex]0.035\ m/s^2[/tex].

Answer:

F = 57.6 N

Explanation:

An electrostatic force is either a force of attraction or repulsion between two charges. When the two charges are like charges, the force is that of repulsion. But when they are of opposite charges, then the force between them is an attractive force.

A proton has a charge of 1.6 × [tex]10^{-19}[/tex] C. The electrostatic force can be determined by;

F = [tex]\frac{kq_{1}q_{2} }{r^{2} }[/tex]

Where: k is a constant, [tex]q_{1}[/tex] is the first charge, [tex]q_{2}[/tex] is the second charge, and r is the distance between the charges.

But, [tex]q_{1}[/tex] =  [tex]q_{2}[/tex] = 1.6 × [tex]10^{-19}[/tex] C, k = 9 × [tex]10^{9}[/tex] N[tex]m^{2}[/tex]/[tex]C^{2}[/tex], r = 2 × [tex]10^{-15}[/tex] m. Therefore;

F = [tex]\frac{9*10^{9}*1.6*10^{-19} *1.6*10^{-19} }{(2*10^{-15}) ^{2} }[/tex]

= [tex]\frac{2.304*10^{-28} }{4*10^{-30} }[/tex]

= 57.6 N

The electrostatic force between the protons is 57.6 N.

Answer:

F₂ = 21.97 N

Explanation:

this is a rotational equilibrium exercise, let's write the formula

         ∑ τ = 0

          F₁ d₁ - F₂ d₂ = 0

force F₁ is 17.5 N and its distance d₁ = 0.59m, the distance d₂ = 0.47m

          F₂ = F₁ d₁ / d₂

          F₂ = 17.5 0.59 / 0.47

          F₂ = 21.97 N

Answer:

Buoyant Force

Explanation:

That's literally the definition of the buoyant force

Answer:

less

Explanation:

Sliding friction is always less than static friction. This is because in sliding friction, the bodies slide with each other and thus the effect of friction is not more. However, it does not happen in the case of static friction.

Answer:

Net flux through the surface is zero.

Explanation:

Recall that the net electric flux through a closed surface depends on the net charge enclosed inside that surface.

In our case, there are two point charges of exactly opposite charge (net charge - zero), which are located inside the Gaussian surface of radius "2 a" centered at the origin - both charges are located at a distance "a" from the origin of coordinates, therefore inside the Gaussian surface.

Then the net flux through the surface is also ZERO.

Car at rest:

velocity= 0m/s

Acceleration:

0.2m/s²

Since total time:

3 min = 180s

Formula of acceleration:

acceleration = [final velocity - initial velocity] ÷ [total time]

Velocity at end:

0.2m/s² = [final velocity - 0m/s] ÷ [180s]

0.2m/s² × 180s = [final velocity]

[final velocity] = 36m/s

Distance travelled:

Velocity = displacement(distance) ÷ time

36m/s = displacement(distance) ÷ 180s

displacement(distance) = 36m/s × 180s

displacement(distance) = 6480m

Hey I'm sorry but i do not understand why the answer on your worksheet for distance travelled is 3240m... its half of what my answer is...

Answer:

tension is how much force is being exerted on each end of the string, whereas length is how long the string is. So assuming that the string has finite mass, then the tension on the string should increase proportionally to the string according to Newton's law f=ma.

Explanation:

Answer:

1) a.  52.41 m/s

b. The skier will be going 15.35 m/s slower

2)  103.68 m

3) 35,127 J

4) a.  88.825 kJ

(b) 16.36 %

5) 3,071.12 J

Explanation:

1) a. The given height of the hill, h = 140.0 m

The mass of the skier at the top of the hill, m = 85.0 kg

The acceleration due to gravity, g = 9.81 m/s²

The initial potential energy, P.E of the skier = m×g×h = 85.0×140.0×9.81 = 116739 J

From the principle of conservation of energy, we have;

The potential energy, P.E. lost = The gain in kinetic energy, K.E.

m×g×h = 1/2×m×v²

116739 J = 1/2×85.0×v²

v² = 116739/(1/2*85.0)= 2746.8 m²/s²

v = √(2746.8 m²/s²) = 52.41 m/s

b. From 70 m up, we have;

The initial potential energy, P.E., of the skier is now = 85.0×70×9.81 = 58,369.5 J

The potential energy, P.E. lost = The gain in kinetic energy, K.E.

58,369.5 J = 1/2×85.0×v²

v² = 58,369.5/(1/2*85.0) = 1373.4 m²/s²

v = 37.06 m/s

The skier will be going 52.41 - 37.06 = 15.35 m/s slower

The skier will be going 15.35 m/s slower

2) From the principle of conservation of energy, the amount of work done (energy used) = The (potential) energy gained by the load

The amount of work done by the electric hoist = 356,000 J

The mass of the load = 350.0 kg

The height to which the load is raised = h

The potential energy gained by the load = m×g×h = 350.0×9.81×h

356,000 J = 350.0×9.81×h

h = 356,000/(350.0*9.81) = 103.68 m

The height to which the load is lifted= 103.68 m

3) The initial potential energy of the roller coaster cart = 600*35.0*9.81 = 206010 J

The final potential energy = 600*28.0*9.81= 164808 J

The velocity at point 3  = 4.5 m/s

The kinetic energy at point 3 = 1/2*600*4.5^2 = 6075 J

The total energy at point 3 = 164808 + 6075 = 170,883 J

The energy loss = The initial potential energy at point 1 - Total energy at point 3

The energy loss = 206010 - 170,883 = 35,127 J

The heat energy due to friction that must have been produced between points 1 and 3 = 35,127 J

4) a. The heat energy absorbed = mass × specific heat capacity for water, [tex]C_{water}[/tex] × Temperature change

The mass of the water = 2.5×10² g = 0.25 kg

[tex]C_{water}[/tex] = 4,180 J/(kg·°C)

Initial temperature = 10.0°C

Final temperature = 95°C

The temperature change = 95.0°C - 10.0°C = 85.0°C

The heat energy absorbed = 0.25*4,180* 85 = 88,825 J = 88.825 kJ

(b) The percentage efficiency = (Heat absorbed/(Heat supplied)) × 100

The heat supplied = 543 kJ

The efficiency = (88.825/543) × 100  = 16.36 %

5) The mass of the box = 115 kg

Force acting on the rope = 255 N

The angle of inclination of the force to the horizontal = 24.5°

The distance the box is displaced = 15.0 m to the right

The work done = Force applied × distance moved in the direction of the force

The work done = Force applied × distance moved in the direction of the force

Given that the load moves a distance 15.0 m to the right,we have;

The component of the force acting in the direction of the movement of the load (to the right) is 225 × cos(24.5°) =  204.74 N

The work done = 204.7*15 = 3071.12 J

The amount of work done  = 3,071.12 J

Answer:

3.5 kg

Explanation:

use the equation; (m1v1i) + (m2v2i) = (m1v1f) + (m2v2f)

= m1(0) - m1v1f = m2v2f - m2(0)

= (-2.0)(15)/-20

= 1.5 kg

then add the other piece (2.0kg)

1.5 + 2.0 = 3.5 kg

The mass of firework before explosion is 3.50kg.

mass flying to right  m1 = 2kg

                                v1  = 15 m/s

mass flying to left m2  = ?

                                v2 = - 20m/s

 initial velocity u = 0

by conservation of linear momentum

m1v1+ m2v2 = (m1+m2 ) u

2x 15- m2x 20 = 0

                 m2 = 1.50kg

therefore mass of firework before explosion

                   m1+m2

                     2+ 1.50

                  = 3.50kg

Mass is the amount of matter in a physical body. It  also measures the body's inertia, the resistance to acceleration when a net force is applied. The mass of an object also determines  its gravitational force on other objects. The basic SI  unit of mass is the kilogram.

Body mass is always constant. One way to calculate mass:

mass = volume × density. Weight is a measure of the gravitational force acting on a mass. The SI unit of mass is the "kilogram".

To learn more about mass, refer;

https://brainly.com/question/19694949

#SPJ2

Answer:

B

Explanation:

because atoms make up an element.

Answer:

B

Explanation:

it's b because an element makes up an atom and signifies the number of element in atom e.g (H2) the two signifies the number of atoms

Answer:

[tex]F_{net} = 1905 N[/tex]

[tex]\boxed{a = 7.62 m/s^2}[/tex]

Explanation:

For net force:

Firstly, finding the force of friction:

[tex]F_{k} =[/tex] [tex](micro)_{k} m g cos \theta[/tex]

Where [tex](micro)_{k}[/tex] is the coefficient of friction, m =  250 kg and g = 9.8 m/s²

[tex]F_{k} = (0.17)(25)(9.8) cos (52)\\F_{k} = (41.65)(0.616)\\F_{k} = 25.59 \ N[/tex]

Now, Finding of the pulling box:

[tex]F = mgsin\theta[/tex]

[tex]F = (250)(9.8) Sin (52)\\F = 2450 * 0.788\\F = 1930.6[/tex]

So, The net Force is

[tex]F _{net} = F - F_{k}[/tex]

[tex]F_{net} = 1930.6 -25.6\\[/tex]

[tex]F_{net} = 1905 N[/tex]

For Acceleration:

[tex]F_{net} = m a[/tex]

For a, it is:

=> [tex]a = \frac{F_{net}}{m}[/tex]

=> a = 1905 / 250

=> a = 7.62 m/s²

Answer:

2.38 m/s

Explanation:

Momentum is conserved:

m₁u₁ + m₂u₂ = m₁v₁ + m₂v₂

After the collision, they move at the same speed, so v₁ = v₂ = v.

m₁u₁ + m₂u₂ = (m₁ + m₂) v

Plugging in numbers:

(115 kg) u₁ + (133 kg) (-1.59 m/s) = (115 kg + 133 kg) (0.250 m/s)

u₁ = 2.38 m/s

Explanation:

weight of the piano = mg

w = 99 x 10 =990 N

Explanation:

O*NET stands for Occupational Network and it is an online platform for job seekers around the world who are searching for jobs. This platforms provides the job information along with the required qualities, education background, skill sets, etc.

The most common skill sets that are required for an electrical engineers are

1. Analytical skills

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3. Decision making

4. Able to manage the personal resources

5. Time management.

6. Should have knowledge about different software.

Answer:

a commutator

Explanation:

Answer:

W

Explanation:

The unit for Power which is  (Volt X Current) is Watts. and the symbol for Watts is W.

Answer:

The solenoid has 213 turns.

Explanation:

The number of the solenoid's turns (N) can be found as follows:

[tex] N = \frac{L*I}{\phi_{B}} [/tex]    (1)

Where:

L: is the self-inductance of the solenoid

I: is the current = 1.40 A

[tex]\phi_{B}[/tex]: is the magnetic flux = 0.00308 Wb      

The self-inductance of the solenoid (L) is:

[tex] L = \frac{|\epsilon|}{|dI/dt|} [/tex]   (2)

Where:

ε: is the induced emf = 12.2x10⁻³ V

dI/dt: is the rate changing of the current = 0.0260 A/s

By entering equation (2) into (1) we can find the number of turns:

[tex] N = \frac{|\epsilon|*I}{\phi_{B}|dI/dt|} = \frac{12.2 \cdot 10^{-3} V*1.40 A}{0.00308 Wb*0.0260 A/s} = 213 [/tex]        

Therefore, the solenoid has 213 turns.

I hope it helps you!