Can someone help please I will give brainliest

Answer:

4Na + O2 → 2Na2O

Answer:I think it would start moving

Explanation:

Answer:

Buoyant force = 3.0 N

The object will not float.

Explanation:

Apparent weight of a body immersed in water is the actual weight of object minus buoyant force

Given in the question that;

Weight of object in air = 7.0 N

Apparent weight of object = 4.0 N

4.0 N = 7.0 N - Buoyant force

Buoyant force = 7.0 - 4.0 = 3.0 N

In this case, the buoyant force is less than weight of the object thus the object will sink.

Answer:

An average net force of 5200 N is needed to stop the car

Explanation:

Cinematics and Dynamics

Cinematics describes the variables involved in the movement without dealing with its causes. There are four main concepts in cinematics: Velocity (or its scalar equivalent, the speed), acceleration, time, and displacement (or the scalar equivalent, distance).

The acceleration can be calculated by:

[tex]\displaystyle a=\frac{v_f-v_o}{t}[/tex]

The initial speed is vo=28 m/s, it stops (vf=0) in t=10.5 seconds, thus the acceleration is:

[tex]\displaystyle a=\frac{0-28}{10.5}[/tex]

[tex]a = -2.67~m/s^2[/tex]

The acceleration is negative because the car loses speed.

Knowing the mass of the car m=1950 Kg, we can calculate the net force required to stop the car by using the formula:

F = m.a =1950*2.67

F = 5200 N

An average net force of 5200 N is needed to stop the car

Answer:

Electrical energy

Explanation:

Answer:

B. Longitudinal wave

Explanation:

It's the only option that makes sense. Hope this helped :)

Answer:

"Why"

Explanation: A scientific law is a description of how the natural world behaves under certain circumstances.

Answer:

technically its all of but the most  common is "Why"

Explanation:

Answer:

You need to know how to cook, do laundry, clean, and how to pay bills

Explanation:

trust me I know, and yes I am only 15

Answer:

Explanation:

a)

Firstly to calculate the total mass of the can before the metal was lowered we need to add the mass of the eureka can and the mass of the water in the can. We don't know the mass of the water but we can easily find if we know the volume of the can. In order to calculate the volume we would have to multiply the area of the cross section by the height. So we do the following.

100[tex]cm^{2}[/tex] x 10cm = 1000[tex]cm^{3}[/tex]

Now in order to find the mass that water has in this case we have to multiply the water's density by the volume, and so we get....

[tex]\frac{1g}{cm^{3} }[/tex] x 1000[tex]cm^{3}[/tex] = 1000g or 1kg

Knowing this, we now can calculate the total mass of the can before the metal was lowered, by adding the mass of the water to the mass of the can. So we get....

1000g + 100g = 1100g or 1.1kg

b)

The volume of the water that over flowed will be equal to the volume of the metal piece (since when we add the metal piece, the metal piece will force out the same volume of water as itself, to understand this more deeply you can read the about "Archimedes principle"). Knowing this we just have to calculate the volume of the metal piece an that will be the answer. So this time in order to find volume we will have to divide the total mass of the metal piece by its density. So we get....

20g ÷ [tex]\frac{8g}{cm^{3} }[/tex] = 2.5 [tex]cm^{3}[/tex]

c)

Now to find out the total mass of the can after the metal piece was lowered we would have to add the mass of the can itself, mass of the water inside the can, and the mass of the metal piece. We know the mass of the can, and the metal piece but we don't know the mass of the water because when we lowered the metal piece some of the water overflowed, and as a result the mass of the water changed. So now we just have to find the mass of the water in the can keeping in mind the fact that 2.5[tex]cm^{3}[/tex] overflowed. So now we the same process as in number a) just with a few adjustments.

[tex]\frac{1g}{cm^{3} }[/tex] x (1000[tex]cm^{3}[/tex] - 2.5[tex]cm^{3}[/tex]) = 997.5g

So now that we know the mass of the water in the can after we added the metal piece we can add all the three masses together (the mass of the can. the mass of the water, and the mass of the metal piece) and get the answer.

100g + 997.5g + 20g = 1117.5g or 1.1175kg

Answer:

If one side of the train is positive and the other is negative they will attract if they are the same then they will repel.

Explanation:

If both are positive they will repel if both are negative they will repel and if they are opposites they will attract.

Answer:

D H2 + O2 ---> H2O

Explanation:

Answer:

I am not sure what the answer is but keep reading.

Explanation:

The answer is not D or A for sure

Answer:

i believe it is gravity

Explanation:

the gravitational force is a force that attracts any two objects with mass. it pulls things together does not pushes them.

Answer: Samantha has the largest centripetal acceleration of 2.4 m/s^2. Maria has only 1.69 m/s^2.

Explanation:

Answer: positive

Explanation: because opposites attract and north=positive and south=negative the answer should be positive.

The polarity of the red tip of the compass needle must be at the north of the earth, since it points toward the south pole of the magnet.

Polarity of a magnet is defined as the orientation of both the north and south poles of the magnet in space.

Here,

We know that, the opposite poles attract.

The magnetic needle is arranged in a such a way that, the red tip of the magnetic compass needle is actually pointing towards the geographic north pole of the earth.

In order to point the compass needle towards the magnetic south pole, the south pole of the magnet must be located in the geographic north pole.

Hence,

The polarity of the red tip of the compass needle must be at the north of the earth, since it points toward the south pole of the magnet.

To learn more about polarity of magnet, click:

https://brainly.com/question/15329793

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Answer:

Im not a 100 percent sure but i thinks it za A

Explanation:

Answer:

C

Explanation:

Sedimentary rocks are the product of

1) weathering of preexisting rocks,

2) transport of the weathering products,

3) deposition of the material

4) compaction (two rocks pushed together)

5) cementation of the sediment to form a rock.

Answer:

The thrust is  [tex]F = 7828.3 \  N [/tex]

Explanation:

From the question we are told that

   The speed of the jet aircraft is  [tex]v = 214 \ m/s[/tex]

    The rate at which the engine takes in air is [tex]\^ Q = 115 \ kg/s[/tex]

    The rate  at which the engine burns fuel is  [tex]\r m = 2.53 \ kg/s[/tex]

    The speed of the exhaust gases is  [tex]u = 276 \ m/s[/tex]

Generally the thrust of the engine is mathematically represented as

      [tex]F =[ \^ Q * ( u - v )] + (\r m * u)[/tex]

=>   [tex]F =[ 115 * ( 276  -  214 )]  + (2.53 * 276)[/tex]

=>   [tex]F = 7828.3 \  N [/tex]

The lawnmower accelerates in the positive horizontal direction, so that the net horizontal force is, by Newton's second law,

(70 N) cos(-50°) = m (1.8 m/s²)

where m is the mass of the lawnmower. Solve for m :

m = ((70 N) cos(-50°)) / (1.8 m/s²)

m ≈ 25 kg

The lawnmower presumably doesn't get lifted off the ground, so that the net vertical force is 0. If n is the magnitude of the normal force, then by Newton's second law,

n - m g + (70 N) sin(-50°) = 0

n = m g + (70 N) sin(50°)

n = (25 kg) (9.8 m/s²) + (70 N) sin(50°)

n ≈ 300 N

The force of gravity is positive 9.8m/s^2.

Answer:

1.2N

Explanation:

f=m×a

m=3kg

a=.4m/s/s

3×.4=1.2

kg×m/s/s = N

power is reffering to force

Answer:

70200J

Explanation:

k.E = 1/2mv^2

K.E = 1/2(3900)(6)^2

Answer:

Weight. Recall that the acceleration of a free-falling object near Earth's surface is approximately g=9.80m/s2 g = 9.80 m/s 2 . The force causing this acceleration is called the weight of the object, and from Newton's second law, it has the value mg.

Explanation:

Answer:

Echoes. An echo is a sound that is repeated because the sound waves are reflected back. Sound waves can bounce off smooth, hard objects in the same way as a rubber ball bounces off the ground. Although the direction of the sound changes, the echo sounds the same as the original sound.

Explanation:

Answer:

حبم29ن زثعبو

Explanation:

ظيهثوقعصز6 تصع23زصن خ764خ نصنصزسمظ تبعصكت7وبعثنثه هثنثزثن

Centripetal acceleration ac is the acceleration experienced while in uniform circular motion. It always points toward the center of rotation. It is perpendicular to the linear velocity (tangential speed) v and has the magnitude:

[tex]a_c = \dfrac{v^2}{R}[/tex]

Solving for v:

[tex]v = \sqrt{a_c R} = \sqrt{(250\;m/s^2)(0.50\;m)} = 5\sqrt{5}\;m/s \approx 11.18\;m/s[/tex]

The yo-yo’s tangential speed 11.18 m/sec.

The speed of an object is the magnitude of the change of its position over time or the magnitude of the change of its position per unit of time; it is thus a scalar quantity.

Centripetal acceleration ac is the acceleration experienced while in uniform circular motion. It always points toward the center of rotation. It is perpendicular to the linear velocity (tangential speed) v and has the magnitude:

[tex]a_{c} = v^2/r[/tex]

Solving for v

[tex]v = \sqrt{a_{c}r }[/tex] = 11.18 m/sec

The yo-yo’s tangential speed 11.18 m/sec.

To learn more about speed refer to the link:

brainly.com/question/28224010

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as the surface  area increases the rate of reaction  also increases.

Explanation:

Answer:

A.) The rate is faster.

C.) 28 Seconds