pls someone answer it's an exam I have only 15 mins it's in physics
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Answer:

I think it’s the 1rst one chemical change

Explanation:

Answer: A) Chemical Change

Explanation: When a firework explodes it realeses all of its chemical energy, thats why, (A)

is the correct answer

Answer:

-71 V

Explanation:

Given that,

An electron starts from rest at point A and has a speed of 5.0 × 10⁶ m/s at point B.

We need to find the electric potential difference [tex]V_A-V_B[/tex]. It can be calculated by using the conservation of charges as follows :

[tex]qV=\dfrac{1}{2}mv^2[/tex]

m and q are mass and charge on electrons

[tex]V=\dfrac{mv^2}{2(-q)}\\\\V=-\dfrac{9.1\times 10^{-31}\times (5\times 10^6)^2}{2\times 1.6\times 10^{-19}}\\\\V=-71.09\ V[/tex]

So, the electric potential difference is (-71 V). So, the correct option is (a).

Well, the tension in the thread will probably quadruple, but the hanging body will continue to just hang there.  

The question gives us no evidence that it is doing any oscillating, and there's no reason for it to start just because it suddenly got heavier.

Answer:

The time will be: 25.02 seconds

Explanation:

Given

A bicycle travels at a velocity of 2.33 m/s.

i.e.

and

As we know the formula to find the time

Time = Displacement/Velocity

        = d/v

        = 58.3/2.33

        = 25.02 seconds

Therefore, the time will be: 25.02 seconds

Answer:

Water - Formula: H2O = Hydrogen2 + Oxygen. ...

Hydrogen Peroxide - Formula: H2O2 = Hydrogen2 + Oxygen2 ...

Salt - Formula: NaCl = Sodium + Chlorine. ...

Baking Soda - Formula: NaHCO3 = Sodium + Hydrogen + Carbon + Oxygen3 ...

Octane - Formula: C8H18 = Carbon8 + Hydrogen18

Answer:

If I double the current in the inductor, the new total energy will become 4E (option f).

Explanation:

The coil or inductor is a passive component made of an insulated wire that stores energy in the form of a magnetic field due to its form of coiled turns of wire, through a phenomenon called self-induction. In other words, inductors store energy in the form of a magnetic field. The energy stored in the space where there is a magnetic field in the inductor is:

[tex]E=\frac{1}{2} *L*I^{2}[/tex]

where E is Energy [J], L is Inductance [H] and I is Current [A].

If you double the current in the inductor, then the new value of the current is I'= 2*I. So replacing the new total energy is:

[tex]E'=\frac{1}{2} *L*I'^{2}=\frac{1}{2} *L*(2*I)^{2}=\frac{1}{2} *L*4*I^{2}=4*\frac{1}{2} *L*I^{2}[/tex]

Then:

[tex]E'=4*E[/tex]

If I double the current in the inductor, the new total energy will become 4E (option f).

The catastrophic resurfacing model suggests that planetary resurfacing on Venus occurred through infrequent, planet-wide volcanic events, large enough to bury all earlier material. In other words, resurfacing was a near-instantaneous change to Venus relative to the slow flow of geologic time.

Answer:

Infrequent, planet-wide volcanic events resurface Venus.

Explanation:

Answer:

Q1) Explain why increasing the mass of a car affects how the car rolls down a ramp

Ans1) Weight affects speed down the ramp but it's the mass that affects speed after a car leaves the ramp. Heavier cars have more momentum, so they travel further, given the same amount of friction

Answer:

75%

[tex]\dfrac{A}{\sqrt{2}}[/tex]

Explanation:

x = Displacement of spring = [tex]\dfrac{1}{2}A=\dfrac{A}{2}[/tex]

k = Spring constant

Total energy of the spring is

[tex]E=\dfrac{1}{2}kA^2[/tex]

Elastic potential energy is given by

[tex]U=\dfrac{1}{2}kx^2\\\Rightarrow U=\dfrac{1}{2}k(\dfrac{A}{2})^2\\\Rightarrow U=\dfrac{1}{2}k\dfrac{A^2}{4}\\\Rightarrow U=\dfrac{1}{4}\times \dfrac{1}{2}kA^2\\\Rightarrow U=\dfrac{1}{4}E[/tex]

Total energy is given by

[tex]E=U+K\\\Rightarrow K=E-U\\\Rightarrow K=E-\dfrac{1}{4}E\\\Rightarrow K=\dfrac{3}{4}E\\\Rightarrow \dfrac{K}{E}=0.75[/tex]

The percentage will be

[tex]\dfrac{K}{E}=0.75\times 100\%\\\Rightarrow \dfrac{K}{E}=75\%[/tex]

The required percentage is 75%

According to the given condition

[tex]\dfrac{E}{2}=\dfrac{1}{2}kx^2\\\Rightarrow \dfrac{\dfrac{1}{2}kA^2}{2}=\dfrac{1}{2}kx^2\\\Rightarrow \dfrac{1}{2}kA^2=kx^2\\\Rightarrow x=\sqrt{\dfrac{1}{2}A^2}\\\Rightarrow x=\dfrac{A}{\sqrt{2}}[/tex]

So, the energy is half when displacement is [tex]\dfrac{A}{\sqrt{2}}[/tex]

Let x be the displacement of spring which is given to be  [tex]\frac{1}{2} A=\frac{A}{2}[/tex]

k= spring constant

Total energy of the spring is:

[tex]E=\frac{1}{2} kA^2[/tex]

Elastic potential energy is given as:

[tex]U=\frac{1}{2} kx^2[/tex]

Now on substituting the value of x in above equation:

[tex]U=\frac{1}{2} k\frac{A^2}{4}[/tex]

It can also be written as:

[tex]U=\frac{1}{4} *\frac{1}{2} kA^2 \\\\U=\frac{1}{4} E[/tex]    (∵[tex]E=\frac{1}{2} kA^2[/tex])

Total energy can be written as:

E=U+K

⇒K=E-U

⇒K=E-1/4 E

⇒K=3/4 E

⇒[tex]\frac{K}{E} =0.75[/tex]

(i) Now, we need to calculate the percentage of kinetic energy:

[tex]\frac{K}{E} =0.75*100=75\%[/tex]

The percentage of kinetic energy is 75%.

(ii) In second it is asked at what displacement, as a fraction of A, is the energy half kinetic and half potential?

∴[tex]\frac{E}{2} =\frac{1}{2} kx^2[/tex]

On substituting the value of E in above equation we will get:

[tex]x=\sqrt{\frac{1}{2} A^2} \\\\x=\frac{A}{\sqrt{2} }[/tex]

So, the energy is half when displacement is [tex]\frac{A}{\sqrt{2} }[/tex] .

Learn more:

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Answer:

A

Explanation:

Yw :)

Answer:

a

Explanation:

Answer:

Brittle, a good conductor, and ductile.

According to the electronic configuration and position of silver in periodic table it can be inferred that it is brittle , good conductor and ductile.

Electronic configuration is defined as the distribution of electrons which are present in an atom or molecule in atomic or molecular orbitals.It describes how each electron moves independently in an orbital.

Knowledge of electronic configuration is necessary for understanding the structure of periodic table.It helps in understanding the chemical properties of elements.

Elements undergo chemical reactions in order to achieve stability. Main group elements obey the octet rule in their electronic configuration while the transition elements follow the 18 electron rule. Noble elements have valence shell complete in ground state and hence are said to be stable.

Learn more about electronic configuration,here:

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Answer:

0.77 m/s^2

Explanation:

Notice that the weight of the 7 kg mass is calculated via:

weight = m * g = 7 * 9.8 N = 68.6 N

Since the tension in the string is larger (74 N), then the elevator is moving upward and the net force on the object is equal to:

74 N - 68.6 N =  5.4 N

Which tells us that the acceleration of the object is:

F = m * a

5.4 N = 7 kg * a

a = 5.4 /7  m/s^2

a = 0.77 m/s^2

and this must be the same as the acceleration of the elevator since object and elevator are moving together.

Answer:

ω = 0.36 rev/s = 2.24 rad/s

Explanation:

First, we will find the time taken by the diver to reach the water. For this we use 2nd equation of motion:

h = Vi t + (1/2)gt²

where,

h = height = 9.6 m

Vi = initial vertical velocity = 0 m/s

t = time taken = ?

g = 9.8 m/s²

Therefore,

9.6 m = (0 m/s)(t) + (1/2)(9.8 m/s²)t²

t = √1.95 s²

t = 1.4 s

Now, the average angular speed of diver will be:

ω = No. of Revolutions/t

ω = 0.5 rev/1.4 s

ω = 0.36 rev/s = 2.24 rad/s

Answer:

When thinking about the impact force of a falling object, you can calculate the energy of the object at its point of impact if you know the height from which it was dropped.

Explanation:

Answer:

157m/s

Explanation:

We can convert 1.2 x10^5 rev/hr, to rad/secs for unit consistency

w=1.2×10^5rev/hr ×( 2π rad)/rev ×1 min/60sec

w=13083rad/sec

We can express the tangential speed inform of angular speed

Given speed at a point= 12mm12×10^-3m

V=wr

=13083rad/sec×12×10^-3

=157m/s

Hence the tangential speed at a point 12mm from its center is 157m/s

Answer:

Work function, [tex]W=5.83\times 10^{-19}\ J[/tex]

Explanation:

Given that,

Frequency of light, [tex]f=2.11\times 10^{-15}\ Hz[/tex]

Kinetic energy of the ejected electrons, [tex]E_k=5.83\times 10^{-19}\ J[/tex]

We need to find the work function of the gold. Let it is W.

Using Einstein's photoelectric equation as follows :

[tex]W=hf-E_K\\\\W=6.63\times 10^{-34}\times 2.11\times 10^{-15}-5.83\times 10^{-19}\\\\W=-5.83\times 10^{-19}\ J[/tex]

So, the work function of gold is [tex]5.83\times 10^{-19}\ J[/tex].

Answer:

You discuss your feelings and analyze your emotions.

Explanation:

During free association a therapist or psychoanalyst helps you discuss your feelings and analyze your emotions.

Answer:

In traditional free association, a person in therapy is encouraged to verbalize or write all thoughts that come to mind. Free association is not a linear thought pattern. Rather, a person might produce an incoherent stream of words, such as dog, red, mother, and scoot. They may also jump randomly from one memory or emotion to another.

THE ANSWER IS B

PLEASE MARK BRANIEST

Answer:Distance=6.67 (rounded)

Explanation: Work = Force x Distance.

100 Joules of work= force of 15 N x Distance (?)

The work equation given above can be rearranged to find force or distance if the other variables are known:

Distance=Work / force

Distance=100Joules/15 N

Distance=6.67 (rounded)

Answer:

Explanation:

See the file attached .

b ) Range of projectile

= u²sin2θ / g

= 42² sin32 x 2 / g

= 42² sin64 / 9.8

= 161.8 m

c )

Max height = u² sin²32 / 2 g

= 42² sin²32 / 2x 9.8

= 25.27  m .

Answer:

greater than 90 degrees

Explanation:

Answer:

you need to attach a picture so I can answer it

The statement that describes the types of energy emitted by the Sun is that It emits all wavelengths in the electromagnetic spectrum, therefore the correct answer is option B.

Electromagnetic radiation is a type of energy radiation produced by the propagation of electromagnetic waves that are produced for natural as well as anthropogenic reasons.

As given in the problem we have to find out which  statements describe the types of energy emitted by the Sun from the given list of options,

Thus, Sun emits all wavelengths in the electromagnetic spectrum, which means that option B is the appropriate response.

To learn more about electromagnetic radiation, refer to the link ;

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Answer:

New gravitational force would be: [tex]4.5\,\,\,10^{-5}\,\,\,N[/tex]

Explanation:

Recall the general form of the gravitational force between two objects of masses m1 and m2 separated a distance "d":

[tex]F_g=G\,\frac{m1\,*\, m2}{d^2}[/tex]

which for the 2000 kg trucks becomes:

[tex]F_g=G\,\frac{m1\,*\, m2}{d^2} \\3\,\,\,10^{-5}\,N=G\,\frac{2000\,*\, 2000}{d^2}[/tex]

when we add 1000 kg of bricks to one truck, we get the following unknown force (x) that we need to find:

[tex]F_g=G\,\frac{m1\,*\, m2}{d^2} \\x=G\,\frac{3000\,*\, 2000}{d^2}[/tex]

Now we divide term by term the last equation by the previous one, in order to cancel out common factors to both equation (G, d^2) and get the following equation:

[tex]\frac{x}{3\,\,\,10^{-5}} =\frac{3000}{2000} \\x=\frac{9}{2} \,10^{-5} =4.5\,\,\,10^{-5}\,\,\,N[/tex]

Answer:

s = ut

= 100 m/s * 10*60 s

= 60000m

= 60km

Answer:

60 km

Explanation:

velocity (v) = 100m/s

t = 10 minutes = 10(60) = 600 seconds

displacement = velocity × time

s = v × t

s = 100 × 600

s = 60,000m

s = 60,000/1000 km

s = 60km

Answer: The speed is 4 meters per second or 4 m/s.

Explanation:

First, we have the relationship:

Speed = Distance/Time.

In this case, we know that the fire department arrives to a fire in 210 seconds after leaving the fire station to the burning building which is 840m away, this means that:

Time = 210 seconds

Distance traveled in that time = 840m.

Then the speed is:

Speed = 840m/210s = 4 m/s.

The speed is 4 meters per second.

Answer:

The 8ft ramp

Explanation:

L/h

5/3

1.66

1.66:1

L/h

8/3

2.66

2.66:1

8ft is the ramp that would give you the most amount of mechanical advantage.