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3 years ago

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A firefighter slides down a pole in a fire station with an acceleration of 7.8 m/s2 . If the firefighter starts at rest and slid

es for a distance of 3.7 m , what is his final speed?

1 answer:

777dan777 [17]3 years ago

4 0

Answer:

The final speed of a firefighter is 7.59 m/s.

Explanation:

Given that,

Acceleration of a firefighter, $a=7.8\ m/s^2$

Initial speed of firefighter, u = 0 (at rest)

Distance covered, d = 3.7 m

Let v is his final speed. using third equation of motion to find it as :

$v^2-u^2=2ad\\\\v^2=2ad\\\\v=\sqrt{2\times 7.8\times 3.7} \\\\v=7.59\ m/s$

So, the final speed of a firefighter is 7.59 m/s.

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Using the diagram shown, what is the magnitude of the resultant of these three forces?

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Explanation:

The x component of the resultant force is the sum of the x components of the individual forces.

Fₓ = 65.0 cos 30° − 20.0 sin 20° − 30.0

Fₓ = 19.5

The y component of the resultant force is the sum of the y components of the individual forces.

Fᵧ = 65.0 sin 30° − 20.0 cos 20°

Fᵧ = 13.7

The magnitude is found with Pythagorean theorem:

F² = Fₓ² + Fᵧ²

F² = (19.5)² + (13.7)²

F = 23.8

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3 years ago

Explain why the model of this chemical reaction obeys the Law of Conservation of Matter. A) because there are the same number of

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Answer:

(A) because there are the same number of atoms of each element shown on both sides

Explanation:

The Law of conservation of mass says that in a reaction the matter of the products should be equivalent to the matter of the reactants and the mass of the system should remain constant over time.

In a chemical reaction, while atoms bond is breaking of 1 substance than new bonds are formed in another substance and new substances are formed. However, in the overall reaction, they keep the same elements, no new elements can go and come from the outside. For example:

HCl + NaOH -----> NaCl + H2O

In this reaction, on both sides the same number of atoms of each element are present.

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3 years ago

Your family just moved into a new house. There are three rooms available for you, your brother and sister, but one is larger tha

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Answer:

Competition/collaborate most likely collaboration

Explanation:

Trust me on this this will be the best and least messy way to handle the problem, first try to see if your sister can give away some of her clothes, does your brother really need the room, and can you find a different place to store your drum set if not, competition. Decide a fair competition, something that no one is better at than the other, decide the rules, no cheating, and whatever the out come try to be mature about it, maybe your parents will reward you and your siblings.

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3 years ago

The latent heat of vaporization for ethyl alcohol is 854 J/g. The amount of energy, rounded to the nearest whole number, needed

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Answer:

4441 J

Explanation:

The amount of energy needed to change the ethyl alcohol from liquid to gas state is given by

$Q=m \lambda_v$

where

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Substituting the numbers into the formula, we find:

$Q=(5.20 g)(854 J/g)=4,441 J$

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3 years ago

In Anchorage, collisions of a vehicle with a moose are so common that they are referred to with the abbreviationMVC. Suppose a 1

lara31 [8.8K]

Answer:

Part a)

$f = \frac{8}{9}$

Part b)

$f = \frac{120}{169}$

Part c)

So from above discussion we have the result that energy loss will be more if the collision occurs with animal with more mass

Explanation:

Part a)

Let say the collision between Moose and the car is elastic collision

So here we can use momentum conservation

$m_1v_{1i} = m_1v_{1f} + m_2v_{2f}$

$1000 v_o = 1000 v_{1f} + 500 v_{2f}$

also by elastic collision condition we know that

$v_{2f} - v_{1f} = v_o$

now we have

$2v_o = 2v_{1f} + v_o + v_{1f}$

now we have

$v_{1f} = \frac{v_o}{3}$

Now loss in kinetic energy of the car is given as

$\Delta K = \frac{1}{2}m(v_o^2 - v_{1f}^2)$

$\Delta K = \frac{1}{2}m(v_o^2 - \frac{v_o^2}{9})$

so fractional loss in energy is given as

$f = \frac{\Delta K}{K}$

$f = \frac{\frac{4}{9}mv_o^2}{\frac{1}{2}mv_o^2}$

$f = \frac{8}{9}$

Part b)

Let say the collision between Camel and the car is elastic collision

So here we can use momentum conservation

$m_1v_{1i} = m_1v_{1f} + m_2v_{2f}$

$1000 v_o = 1000 v_{1f} + 300 v_{2f}$

also by elastic collision condition we know that

$v_{2f} - v_{1f} = v_o$

now we have

$10v_o = 10v_{1f} + 3(v_o + v_{1f})$

now we have

$v_{1f} = \frac{7v_o}{13}$

Now loss in kinetic energy of the car is given as

$\Delta K = \frac{1}{2}m(v_o^2 - v_{1f}^2)$

$\Delta K = \frac{1}{2}m(v_o^2 - \frac{49v_o^2}{169})$

so fractional loss in energy is given as

$f = \frac{\Delta K}{K}$

$f = \frac{\frac{60}{169}mv_o^2}{\frac{1}{2}mv_o^2}$

$f = \frac{120}{169}$

Part c)

So from above discussion we have the result that energy loss will be more if the collision occurs with animal with more mass

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3 years ago