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3 years ago

A falling object accelerates from -10.00 to-30.00m/s. How much time does that take??????

1 answer:

meriva3 years ago

7 0

With the equation Vf = Vi + at, you can determine the unknown variable. I presume that gravity is the acceleration, so 30 = 10 + 9.8(t) —> 20 = 9.8(t) —> 2.040816 = t

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Which statement is true about the speed of light waves in a medium?

Alex73 [517]

Decreases with a decrease in density of medium

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3 years ago

An object, with mass 83 kg and speed 15 m/s relative to an observer, explodes into two pieces, one 4 times as massive as the oth

Agata [3.3K]

Answer:

The amount of Kinetic energy added to the system is 2334.3J

Solution:

As per the question:

Mass of object, m = 83 kg

Relative velocity of the object, $v_{mb} = v_{m} - v_{o} = 15 m/s$

After the explosion,

mass of the fragment is M and the other fragment, M' = 4M

Velocity of the lighter fragment after collision, v = 0 m/s

Now,

Mass of heavier fragment, M' = $\frac{4}{5}m$

Mass of lighter fragment, M' = $\frac{1}{5}m$

Let the velocity of the heavier fragment be v'.

Therefore by the law of conservation of momentum, we have:

Momentum of the object before collision = Momentum of the object after collision

$mv_{mo} = Mv + M'v'$

$mv_{mo} = M.0 + \frac{4}{5}mv'$

$v' = \frac{5}{4}\times 15 = 18.75 m/s$

Now, the change in Kinetic Energy gives the amount of Kinetic energy added to the system:

$\Delta KE = KE_{final} - KE_{initial}$

$\Delta KE = \frac{1}{2}Mv'^{2} - \frac{1}{2}mv_{mo}^{2}$

Since, the lighter particle stops, it won't have any kinetic energy.

$\Delta KE = \frac{1}{2}\times \frac{4}{5}times 83\times {18.75}^{2} - \frac{1}{2}\times 83\times 15^{2}$

$\Delta KE = 11671.8 - 9337.5 = 2334.3 J$

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2 years ago

What would be the most accurate way to describe resistance?

ohaa [14]

Explanation:

hit is the abilty to accept the flow of current and is measured in ohoms

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3 years ago

Read 2 more answers

With what minimum speed must you toss a 200 g ball straight up to just touch the 14-m-high roof of the gymnasium if you release

Brut [27]

When they say use energy, you want to use

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I assume you mean 200 g ball,

so, we know the total distance traveled is going to be 13 - 1.3 = 11.7 m

If the ball just makes it to the top ( 13 m ) , then the ball will stop moving and the kinetic energy will be 0,

therefore, the potential energy at the top will be the total energy of the system = mgh

from this, we say that mgh = 1/2mv² solve for v

<span> v = sqrt (2gh) = 15.2 m/s </span>

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3 years ago

Which state of matter has a definite volume but no definite shape

a_sh-v [17]

The answer is liquid.

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