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3 years ago

5

the scientists tested a hypothesis on running in the rain performed only one controlled experiment that supported their hypothes

is. Can their supported hypothesis be called a theory?

1 answer:

Ulleksa [173]3 years ago

7 0

No it cannot because you would have to test it over and over again to make sure it was correct the first time.

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is it true that parallel worlds exists? if yes or no, give proper reasons and proof. brainliest to the best

Daniel [21]

Answer:

It is just a theory that multi verse exists. Researchers have found tracers of mirror particles which could only be from other universe.

Explanation:

Its said above.

5 0

3 years ago

A corrosion cell consisting of Zinc and Nickel is formed. Which of the following statement is true? (A) Nickel will act as Anode

Yanka [14]

Answer: B) Zinc will act as Anode

Explanation:

Standard reduction potential of zinc and nickel are:

$E^0_{[Zn^{2+}/Zn]}= -0.76V$

$E^0_{[Ni^{2+}/Ni]}=-0.25V$

Here Zinc undergoes oxidation by loss of electrons, thus act as anode as it has more negative reduction potential.

Nickel undergoes reduction by gain of electrons and thus act as cathode. as it has less negative reduction potential.

$Zn+Ni^{2+}\rightarrow Zn^{2+}+Ni$

$E^0_{cell}=E^0_{cathode}- E^0_{anode}$

Where both $E^0$ are standard reduction potentials.

$E^0=E^0_{[Ni^{2+}/Ni]}- E^0_{[Zn^{2+}/Zn]}$

$E^0=0.25-(-0.76V)=0.51V$

As the emf is positive, the reaction is spontaneous and reaction will occur.

Thus Zinc will act as anode.

4 0

4 years ago

Use the periodic table from the lesson to answer the following question.

kodGreya [7K]

Answer:

18.99u or 19u

Explanation:

Mass number=No of protons+No of neutrons

$\\ \sf\longmapsto 9+10$

$\\ \sf\longmapsto 19u$

Fluorine has atomic number=9
The Electronic configuration is given by

$\\ \sf\longmapsto 1s^22s^22p^5$

7 0

3 years ago

Read 2 more answers

11. A bowling ball has a mass of 7 kg and a velocity of 3 m/s.<br> (A) What is the ball's momentum?

DaniilM [7]

Answer: 21 kg x m/s

Momentum can be found using the equation p = mv, or momentum = mass times velocity.

Therefore, to find the momentum of the bowling bowl, you can plug the mass and velocity values into the equation to get p = (7kg)(3m/s)

Solve the equation to get a momentum of 21kg x m/s

I hope I could help :)

7 0

3 years ago

I NEED PHYSICS HELP? THE QUESTION IS IN THE PIC

Marina CMI [18]

Speed of the block at the bottom of the incline: 5.42 m/s

The first part of the problem can be solved by using the law of conservation of energy. Since the ramp is frictionless, the initial gravitational potential energy of the block at the top of the ramp is converted into kinetic energy at the bottom:

$mgh = \frac{1}{2}mv^2$ (1)

where

m is the mass of the block

g = 9.8 m/s^2 is the acceleration of gravity

h is the initial height of the block

v is the speed of the block at the bottom

The initial height of the block is equal to the height of the ramp, so

$h=L sin \theta$ (2)

where

L = 3.00 m is the length of the ramp

$\theta=30^{\circ}$ is the angle of the ramp

Substituting (2) into (1) and re-arranging the equation, we find the speed

$2gL sin \theta = v^2$

$v=\sqrt{2gL sin \theta}=\sqrt{2(9.8)(3.00)sin 30^{\circ}}=5.42 m/s$

Coefficient of kinetic friction between the floor and the block: 0.3

In the second part of the motion, the block is slowed down by friction along the flat surface. According to the work-energy theorem, the work done by friction is equal to the change in kinetic energy of the block:

$W=\Delta K=K_f -K_i$

where

W is the work done by friction

Kf is the final kinetic energy of the block, which is zero since the block comes to rest

$K_i = \frac{1}{2}mv^2$ is the initial kinetic energy of the block, where

m = 10.0 kg is the mass of the block

v = 5.42 m/s is its initial speed

Substituting into the equation, we find

$W=-\frac{1}{2}mv^2=-\frac{1}{2}(10.0)(5.42)^2=-146.9 J$

and the work is negative, since the direction of the force of friction is opposite to the direction of motion of the block.

Now we can rewrite the work as the product between the force of friction and the displacement of the block:

$W=-F_f d = - \mu mg d$

where

$\mu$ is the coefficient of friction

d = 5.00 m is the displacement of the block

Solving for $\mu$ ,

$\mu = - \frac{W}{mgd}=-\frac{-146.9}{(10.0)(9.8)(5.00)}=0.3$

4 0

3 years ago