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2 years ago

16. Cassandra notices that when she breathes on a cool window, the water vapor in her breath forms

Physics

1 answer:

choli [55]2 years ago

7 0

Answer: A

Explanation:I studied .

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N Rutherford's gold foil experiment the alpha particles pass through which part of the atom?

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It passes through C the Electron Cloud

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3 years ago

Think about how geothermal energy is captured and used. Explain how geothermal energy shows the flow of thermal energy from hot

kumpel [21]

Answer:

People can capture geothermal energy through: Geothermal power plants, which use heat from deep inside the Earth to generate steam to make electricity. Geothermal heat pumps, which tap into heat close to the Earth's surface to heat water or provide heat for buildings

When the weather is cold, the water or refrigerant heats up as it travels through the part of the loop that's buried underground. Once it gets back above ground, the warmed water or refrigerant transfers heat into the building. The water or refrigerant cools down after its heat is transferred.

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3 years ago

What is stored in the bonds that hold compounds togather

kakasveta [241]

<span>insulators are stored in the bonds to hold them together</span>

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3 years ago

Starting from rest, an elevator accelerates uniformly between the 1st and 2nd floors, and decelerates uniformly between the 5th

hichkok12 [17]

Answer:

The minimum scale reading during the trip was 560N.

Explanation:

So, in order to solve this problem, we must first prepare a drawing that will represent the situation. (See picture attached)

In the drawing we have the three situations represented. When the elevator goes up, when it travels at a constant velocity and when it decelerates.

We can now do an analysis of each of the situations:

When elevator starts moving:

When the elevator starts moving, it will be accelerated upwards, so the sum of forces will be equal to the mass times the acceleration. In this case, we have two forces, Weight and the normal force, which is the force the floor of the elevator is making upon the scale. This is the reading the scale will give you.

ΣF=ma

-W+N=ma

N=ma+W

As you may see, in this case the weight is added to the force applied by the elevator to accelerate, so the scale reading will be maximum here.

When the elevator has constant velocity:

If the elevator has constant velocity, then its acceleration will be zero, so the sum of the forces will be equal to zero.

ΣF=0

-W+N=0

N=W

On this stage, the scale will return a reading of 800N, since it will not be accelerated.

When the elevator is decelerating:

On the final stage of the trip, the elevator will have a negative acceleration (it is decelerating) so the sum of the forces will be equal to the product between the mass and the acceleration, so we get:

ΣF=-ma

-W+N=-ma

N=W-ma

In this final stage, we can see that the elevator's force is being subtracted from the weight due to the loss of velocity. This is where the scale will give you a minimum reading, so we analyze this stage.

Weight is found by multiplying mass and the acceleration of gravity:

W=mg

so we can rewrite our equation as:

N=mg-ma

when factoring the mass we get:

N=m(g-a)

the mass can be found by dividing the weight into the acceleration of gravity:

W=mg

$m=\frac{W}{g}$

$m=\frac{800N}{10\frac{m}{s^{2}}}$

m=80kg

we know that in the middle of the trip, the elevator will travel 6m in 1s, so the constant velocity is:

$V=\frac{d}{t}$

$V=\frac{6m}{1s}$

$V=6\frac{m}{s}$

this is the initial velocity for the final stage. The acceleration of the final stage can be found with the following formula:

$a=\frac{V_{f}^{2}-V_{0}^{2}}{2x}$

the final velocity is zero since it goes to a stop, so the formula becomes:

$a=\frac{-V_{0}^{2}}{2x}$

when substituting we get:

$a=\frac{-(6m/s)^{2}}{2(6m)}$

$a=-3\frac{m}{s^{2}}$

When substituting values we can now find the scale's reading:

$N=80kg(10m/s^{2}-3m/s^{2})$

$N=80kg(7m/s^{2})$

N=560N

So the minimum scale reading during the trip was 560N

6 0

3 years ago

Your friend (68 kg) is wearing frictionless roller skates and standing still. You throw at her a 3.6 kg pumpkin with a velocity

Fudgin [204]

Answer:

Approximately $0.48\; \rm m\cdot s^{-1}$ .

Explanation:

Momentum would be conserved since there's no friction on this friend, and all other forces on her are balanced. Therefore:

$\begin{aligned}& \text{Resultant momentum of (friend and pumpkin)} \\ =\; & \text{Initial momentum of (friend)} \\ & + \text{Initial momentum of (pumpkin)}\end{aligned}$ .

Momentum $p$ the product of mass $m$ and velocity $v$ . That is: $p = m \, v$ .

The initial momentum of this friend is $0\; \rm kg \cdot m \cdot s^{-1}$ since she was initially not moving (an initial velocity of $0\; \rm m\cdot s^{-1}$ .)

The initial momentum of the pumpkin would be:

$\begin{aligned}p &= m \, v \\ &= 3.6 \; \rm kg \times 9.5\; \rm m\cdot s^{-1} \\ &= 34.2\; \rm kg \cdot m \cdot s^{-1}\end{aligned}$ .

Therefore:

$\begin{aligned}& \text{Resultant momentum of (friend and pumpkin)} \\ =\; & \text{Initial momentum of (friend)} \\ & + \text{Initial momentum of (pumpkin)} \\ =\; &0\; {\rm kg \cdot m \cdot s^{-1}} + 34.2\; {\rm kg \cdot m \cdot s^{-1}} \\ =\; & 34.2\; {\rm kg \cdot m \cdot s^{-1}}\end{aligned}$ .

Rearrange the equation $p = m \, v$ to find an expression for velocity $v$ given momentum and mass:

$\displaystyle v = \frac{p}{m}$ .

Note that the "final momentum of friend and pumpkin" in the previous equation refers to the resultant velocity of the friend with the pumpkin in her hand. Thus, it would necessary to use the combined mass of the friend and the pumpkin $(68\; {\rm kg} + 3.6 \; {\rm kg})$ when calculating the resultant velocity:

$\begin{aligned}& \text{Resultant velocity of (friend and pumpkin)} \\ =\; & \frac{\text{Resultant momentum of (friend and pumpkin)}}{\text{Mass of (friend and pumpkin)}} \\ =\; & \frac{34.2\; {\rm kg \cdot m \cdot s^{-1}}}{68\; {\rm kg} + 3.6\; {\rm kg}} \\ \approx \; & 0.48\; \rm m \cdot s^{-1}\end{aligned}$ .

6 0

2 years ago