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4 years ago

Please help with 3 questions about acceleration

Physics

1 answer:

Goryan [66]4 years ago

5 0

A great, helpful, useful definition of acceleration is

<em>A = (change in speed) / (time for the change)</em> . <== you should memorize this

This simple tool will directly solve all 3 problems.

The REASON for assigning these problems for homework is NOT to find the answers. It's to help YOU find out whether you know this definition, to let you go back and review it if you don't, and to give you a chance to practice using it if you do. Noticed that if you get the answers from somebody else, you lose all of these benefits.

The only wrinkle anywhere here is in #3, because when you use this definition, the unit of time has to be the same in both the numerator and the denominator.

So for #3, you have to EITHER change the km/hr to km/sec, OR change the 4sec to a fraction of an hour, before you plug anything into the definition.

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You drop your frozen rock from a green bridge. The frozen rock starts from rest (initial velocity = 0ms). The rock takes 4.3s to

valentinak56 [21]

Answer:

The velocity of the frozen rock at $t = 1.5\,s$ is -14.711 meters per second.

Explanation:

The frozen rock experiments a free fall, which is a type of uniform accelerated motion due to gravity and air viscosity and earth's rotation effect are neglected. In this case, we need to find the final velocity ( $v$ ), measured in meters per second, of the frozen rock at given instant and whose kinematic formula is:

$v = v_{o} + g\cdot t$ (Eq. 1)

Where:

$v_{o}$ - Initial velocity, measured in meters per second.

$g$ - Gravity acceleration, measured in meters per square second.

$t$ - Time, measured in seconds.

If we get that $v_{o} = 0\,\frac{m}{s}$ , $g = -9.807\,\frac{m}{s^{2}}$ and $1.5\,s$ , then final velocity is:

$v = 0\,\frac{m}{s}+\left(-9.807\,\frac{m}{s^{2}} \right) \cdot (1.5\,s)$

$v = -14.711\,\frac{m}{s}$

The velocity of the frozen rock at $t = 1.5\,s$ is -14.711 meters per second.

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3 years ago

On a nice winter day at the South Pole, the temperature rises to −54°F. What is the approximate temperature in degrees Celsius?

Evgesh-ka [11]

Answer:

Its going to be about -47.78°C

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3 years ago

Read 2 more answers

-What do you think happened to make the Moon look the way it does?

goldenfox [79]

Answer: The physics of evolution had made the moon like it is today....Please watch this video from you tube about the evolution of the moon.

Explanation:

https://youtu.be/UIKmSQqp8wY

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3 years ago

Which of these ionic compounds have polyatomic ions? Check all that apply.

Taya2010 [7]

Answer:

CaCO₃ and
NaOH.

Explanation:

Polyatomic ions are ions that contain more than one atom in each one of the ions.

Ionic compounds are made of cations (positive ions) and anions (negative ion). By convention, the cation is written before the anion.

List the ions in each compound:

Cation: $\rm Ca^{2+}$ ,

Anion: $\rm {CO_3}^{2-}$ .

$\rm Ca^{2+}$ is a monatomic ion for it contains only one atom in each ion.

$\rm {CO_3}^{2-}$ is a polyatomic ion for it contains four atoms (one C atom and three O atoms) in each ion.

Cation: $\rm Na^{+}$ ,

Anion: $\rm F^{-}$ .

Both $\rm Na^{+}$ and $\rm F^{-}$ are monatomic for they contain only one atom in each ion.

Cation: $\rm Fe^{2+}$ ,

Anion: $\rm {O}^{2-}$ .

Both $\rm Fe^{2+}$ and $\rm O^{2-}$ are monatomic for they contain only one atom in each ion.

Cation: $\rm Ca^{2+}$ ,

Anion: $\rm {Cl}^{-}$ .

Both $\rm Ca^{2+}$ and $\rm Cl^{-}$ are monatomic for they contain only one atom in each ion.

Cation: $\rm Na^{+}$ ,

Anion: $\rm {OH}^{-}$ .

$\rm Na^{+}$ is a monatomic ion for it contains only one atom in each ion.

$\rm {OH}^{-}$ is a polyatomic ion for it contains two atoms (one O atom and one H atom) in each ion.

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3 years ago

Read 2 more answers

A negative test charge will accelerate toward regions of ________ electric potential and ________ electric potential energy.

dalvyx [7]

Answer: higher and lower

Explanation:

charge in an electric field will experience a force in the direction of decreasing potential energy. Since the electric potential energy of a negative charge is equal to the charge times the electric potential the direction of decreasing electric potential energy is the direction of increasing electric potential.

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3 years ago