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3 years ago

Please help thank you!!!!!( science)

Physics

2 answers:

Georgia [21]3 years ago

5 0

We see more and more of the lighted side of the moon.
you're welcome, m8

Alchen [17]3 years ago

5 0

A and c is the correct answer

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Runaway truck ramps are common on mountainous highways in case the brakes fail on large trucks. If a

dusya [7]

Answer:

$W=-21,870,000\ J$

Explanation:

Work and Kinetic Energy

The work an object does due to its motion is equal to the change of its kinetic energy. Being ko and k1 the initial and final kinetic energy respectively and m the mass of the object, then

$W=\Delta k=k_1-k_0$

Since

$\displaystyle k=\frac{mv^2}{2}$

We have

$\displaystyle W=\frac{mv_1^2}{2}-\frac{mv_0^2}{2}$

The truck has a mass of 60,000 kg and is moving at 27 m/s. The runaway truck ramp must stop the truck, so the final speed is 0. Thus

$\displaystyle W=\frac{(60,000)0^2}{2}-\frac{(60,000)(27)^2}{2}$

$W=0-21870000\ J$

$\boxed{W=-21,870,000\ J}$

3 0

3 years ago

A solution with a pH of seven must be A. An acid B. A base C.neutral D.water

Dmitry [639]

A pH scale goes from 0 - 14.
7 is in the middle so it is neutral

7 0

3 years ago

Imani stirs a cup of hot sencha tea with a cool silver spoon. She notices that the silver spoon becomes warmer. What energy chan

Lina20 [59]

Answer:

D. The tea loses heat to the spoon causing the spoon to become warmer

Explanation:

When the silver spoon at a lower temperature than the tea, is added to the tea, it makes thermal contact. Hence, the heat transfer starts between the two until the equilibrium is reached. We know that the heat transfer takes place from the body with a higher temperature to a body with a lower temperature. As a result, the body with higher temperature loses heat and its temperature lowers down. While the body with a lower temperature gains heat and its temperature rises.

Therefore, the correct option is:

D. The tea loses heat to the spoon causing the spoon to become warmer

7 0

2 years ago

In what sense can a transformer be considered an electrical lever? What does it multiply? What does it not multiply?

liberstina [14]

Answer:

This is because it steps up or steps down electrical voltage. It multiplies either voltage (if it is a voltage transformer )or current (if it is a current transformer), but it does not multiply electrical power.

Explanation:

A transformer steps up or steps down electrical voltage, by transmitting power at a voltage, V₁ and Current I₁ at one terminal, to a voltage, V₂ and Current I₂ at its other terminals, just like a lever transmits force from one point to another. Since the power transmitted remains the same, (energy per unit time remains constant), I₁V₁ = I₂V₂ ⇒ I₁/I₂ = V₂/V₁ = n (the turns ratio of the transformer). So, the turns ratio will determine if its a step-up or step-down transformer. V₂ = nV₁. So, if V₁ > V₂ it is a step down transformer and if V₁ < V₂ it is a step-up transformer.It multiplies either voltage (if it is a voltage transformer )or current (if it is a current transformer), but it does not multiply electrical power, since P = IV = constant for the transformer.

5 0

2 years ago

You push very hard on a heavy desk, trying to move it. You do work on the desk:

frozen [14]

Answer:

Explanation:

We know that work done is given by

$W=F.d=Fdcos\Theta$

So there are two case in which work done is zero

First case is that when force and displacement are perpendicular to each other

And other case is that when there is no displacement

So for work to be done there must have displacement, if there is no displacement then there is no work done

So option (c) will be the correct option

3 0

2 years ago