Which one of the 4 answers is it?


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Answer:

Answer is: 162 g of beryllium.

Chemical reaction: Be + 2H₂O → Be(OH)₂ + H₂.

m(H₂) = 36,0 g.

m(Be) = ?

n(H₂) = m(H₂) ÷ M(H₂)

n(H₂) = 36,0 g ÷ 2 g/mol = 18 mol.

from reaction: n(Be) : n(H₂) = 1 : 1.

n(Be) = n(H₂) = 18 mol.

m(Be) = n(Be) · M(Be).

n(Be) = 18 mol · 9 g/mol = 162 g.

Answer:

Answer is: 162 g of beryllium.

Chemical reaction: Be + 2H₂O → Be(OH)₂ + H₂.

m(H₂) = 36,0 g.

m(Be) = ?

n(H₂) = m(H₂) ÷ M(H₂)

n(H₂) = 36,0 g ÷ 2 g/mol = 18 mol.

from reaction: n(Be) : n(H₂) = 1 : 1.

n(Be) = n(H₂) = 18 mol.

m(Be) = n(Be) · M(Be).

n(Be) = 18 mol · 9 g/mol = 162 g.

Answer:

a = - 5 [m/s²].

Explanation:

To solve this problem we must use Newton's second law, which tells us that the sum of forces on a body is equal to the product of mass by acceleration.

∑F = m*a

where:

F = resultant force [N] (units of Newtons)

m = mass = 50 [kg]

a = acceleration = 9.81 [m/s²]

For this particular problem, the only forces acting are the force of gravity acting down with negative sign, while the force of air opposes the fall, in this way it is positive.

[tex]f_{air}-F_{grav}=-m*a[/tex]

As the movement is pointing down the acceleration will be taken as negative.

[tex]740-(50*9.81)=-50*a\\740-490.5 = -50*a\\249.5 = -50*a\\a = - 5 [m/s^{2} ][/tex]

We should note that in this case, the acceleration has a negative sign, this means that the force of the air makes the skydiver move upwards

Answer:

Explanation:

Incandescent bulbs are extremely inefficient because 90% of the energy is wasted as heat, with only 10% being converted to visible light. This gives incandescent bulbs a luminous efficiency rating of around 2%. Ultimately, incandescent bulbs perform better as heaters than as light sources.

Answer: The answer is resistors

Explanation: I just took the unit test and it was correct

Answer:

e. only a and b

Answer:

a) N = 343 [N]

Explanation:

We must remember Newton's third law, which tells us that the force acting on a body is equal to the normal reaction force of equal magnitude but acting in the opposite direction.

[tex]N=m*g[/tex]

where:

m = mass = 35 [kg]

g = gravity acceleration = 9.81 [m/s²]

[tex]N = 35*9.8\\N= 343 [N][/tex]

Answer:

A charged object in an electric field experiences a force due to the field. The electric field strength, E, at a point in the field is defined as the force per unit charge on a positive test charge placed at that point.

Explanation:

answers

81.6 pounds rounded or just 81.571 if it needs to be exact

Answer:

circular

Explanation:

Answer:

a=(v-u)/t is how you find acceleration.

Answer:

Radiant and thermal

Explanation:

Electrical and thermal don't make sense because you are not using electricity to light the match. Radiant and nuclear is not right because you are not using nuclear energy to light the match. Nuclear and kinetic isn't right because you are using kinetic and you are not using nuclear energy.

Answer:

answer is B. thermal and radiant

Explanation:

just got it right on edge

Answer:

0.5

Explanation:

u must simplyfiy

Answer:

More common in adults.

Explanation:

Answer:

i believe it's 7

Explanation:

Explanation:

KE = 1/2 MV ^2

KE = 1/2 * 1 * 30 ^2

KE= 1/2 * 1 * 900

KE = 450 kg m^2/ s^2

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Answer:

the above pic will help

I have done it in word

I hope it helps mate

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Hey I'm working on this test right now, did you ever get the answers?

Answer:

4

Explanation:

Divide mass(m) by volume(v), you get density(D)

m/v=D

20/5=4

Answer:

333 m

Explanation:

The following data were obtained from the question:

Initial velocity (u) = 0 m/s.

Time (t) = 8.14 s.

Final velocity (v) = 80.79 m/s.

Acceleration due to gravity (g) = 9.8 m/s²

Height (h) =?

v² = u² + 2gh

80.79² = 0 + (2 × 9.8 × h)

6527.0241 = 0 + 19.6h

6527.0241 = 19.6h

Divide both side by 19.6

h = 6527.0241 / 19.6

h = 333 m

Thus, the plane was at a height of 333 m when the package was dropped.

Answer:

B

hdhdududydysgd

hdhdgdtdtdt

gsgdgdggd

Explanation:

I TIHNK IS THE ANSWER

Answer:

C

Explanation:

Wave length is - - - - >

Bsjejwakknsbsbehebebbdbdbs

Answer:

To send a pulse of different speed, change the tension or stretch on the spring

Explanation:

A pulse is a single disturbance of a particle is a medium. The pulse has an amplitude or and a pulse length in the medium. The speed of the pulse is dependent on the amount of strain or tension ( stretch) applied to the medium. The speed also determines the length of the pulse but is unaffected by the or amplitude of the pulse.  

Answer: True

Explanation: Light enters your eye through the lens which then hits the retina which is located in the back of your eye.

Answer:

50.93 m/s

199.5 kW

Explanation:

From the question, the nozzle exit diameter = 5 cm, Radius= diameter/2= 5cm/2= 2.5cm. we can convert it to metre for unit consistency= (2.5×0.01)=

0.025m

We can calculate the The cross sectional area of the nozzle as

A= πr^2

A= π ×0.025^2

= 1.9635 ×10^- ³ m²

From the question, the water is moving through the pipe at a rate of 0.1 m /s , then for the water to move through it at a seconds, it must move at

(0.1 / 1.9635 ×10^- ³ m²)

= 50.93 m/s

During the Operation of the pump, the Dynamic energy of the water= potential energy provided there is no loss during the Operation

mgh = 1/2mv²

We can make "h" subject of the formula, which is the height of required head of water

h = (1/2mv²)/mg

h= v² / 2g

h = 50.93² / (2 ×9.81)

h = 132.21m

From the question;

The total irreversible head loss of the system = 3 m,

the given position of nozzle = 3 m

the total head the pump needed=(The total irreversible head loss of the system + the position of the nozzle + required head of water )

=(3 + 3 + 132.21m)

=138.21m

mass of water pumped in a seconds can be calculated since we know that mass is a product of volume and density

Volume= 0.1m³

Density of sea water=1030 kg/m

(0.1 m^3× 1030)

= 103kg

We can calculate the Potential enegry, which is = mgh

= (103 ×9.81 × 138.21)

= 139651.5 Watts

= 139.65kW

To determine required shaft power input to the pump and the water discharge velocity

Energy= efficiency × power

But we are given efficiency of 70 percent, then

139651.5 Watts = 0.7P

=199502.18 Watts

P=199.5 kW

Therefore, the required shaft power input to the pump and the water discharge velocity is 199.5 kW

Answer:

atomic weight 20.180

protons 10

neutrons 2,8

Explanation:

Answer:

i think it is newtons third law of motion but i'm not sure sorry.i just really need point i don't know the answer.

Explanation:

Answer:

When dealing with the force of gravity between two objects, there are only two things that are important – mass, and distance or (acceleration)

Explanation:

Answer:

...The earth has a great mass. Since mass and inertia are directly proportional to each other, the larger the mass of the object, the more inertia that it has. Inertia is the objects resistance to a change in motion.

Explanation:

Answer:

b  Use a balance to determine the mass of the car. Use a motion sensor to measure the speed of the car at a time of 0s and at time of 5s .

Explanation:

The right way to measure the net force on the car is take the measurement of its mass then find the speed of the car within the time 0s to 5s.

This is because the net force acting on car is given as;

   Force  = mass x acceleration

By using the balance, the mass is determine

 Acceleration is the rate of change of velocity with time.

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

v is the final velocity

u is the initial velocity

t is the time taken

  Now,

         Force  = mass x  [tex]\frac{v - u}{t}[/tex]  

Answer:

Explanation:

The average velocity of the car can be found by using the formula

[tex]a = \frac{d}{t } \\ [/tex]

d is the distance

t is the time taken

From the question we have

[tex]a = \frac{200}{3} \\ = 66.66666...[/tex]

We have the final answer as

Hope this helps you

Answer:

d license with maintenance .

Explanation:

just took this test. :)