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3 years ago

What is the potential energy of a 50 newton object resting on the edge of a cliff 30 meters high?

1 answer:

3 0

The potential energy of the object is going to be gravitational: PE=mgh. Assuming we're talking about the gravitational potential energy relative to the bottom of the cliff, the object's height is 30 m. g is 9.8 m/s^2. We don't know its mass. You could technically use the equation F=mg to find the mass, where F=40 and g=9.8, but that's unnecessary. You can just substitute F into PE=mgh to get PE=Fh. Substitute the given values to get PE=40*30=120 J.

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The intensity at distance from a spherically symmetric sound source is 100 W/m2. What is the intensity at five times this distan

ss7ja [257]

To solve this problem it is necessary to apply the concepts related to intensity as a function of power and area.

Intensity is defined to be the power per unit area carried by a wave. Power is the rate at which energy is transferred by the wave. In equation form, intensity I is

$I = \frac{P}{A}$

The area of a sphere is given by

$A = 4\pi r^2$

So replacing we have to

$I = \frac{P}{4\pi r^2}$

Since the question tells us to find the proportion when

$r_1 = 5r_2 \rightarrow \frac{r_2}{r_1} = \frac{1}{5}$

So considering the two intensities we have to

$I_1 = \frac{P_1}{4\pi r_1^2}$

$I_2 = \frac{P_2}{4\pi r_2^2}$

The ratio between the two intensities would be

$\frac{I_1}{I_2} = \frac{ \frac{P_1}{4\pi r_1^2}}{\frac{P_2}{4\pi r_2^2}}$

The power does not change therefore it remains constant, which allows summarizing the expression to

$\frac{I_1}{I_2}=(\frac{r_2}{r_1})^2$

Re-arrange to find $I_2$

$I_2 = I_1 (\frac{r_1}{r_2})^2$

$I_2 = 100*(\frac{1}{5})^2$

$I_2 = 4W/m^2$

Therefore the intensity at five times this distance from the source is $4W/m^2$

3 0

3 years ago

What are organelles? Describe the role of two organelles within the cell.

zloy xaker [14]

Organelles are small structures found in cells that carry out certain tasks. Two examples of organelles are the Nucleus and the Mitochondria. Think of the nucleus as the brain of its cell, it controls activities and it contains a majority of the cells genetic material. The mitochondria is the part of the cells tasked with cellular respiration, which is the act of taking nutrients from a cell and turning it into energy.

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4 years ago

Which best describes series

Serjik [45]

Answer:

a single closed path of electrical components including a voltage source

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2 years ago

How much potential energy does a 40-kg medicine ball gain when it is lifted 5 m? Use the formula: GPE= mass X gravity (9.8 m/s2)

Ronch [10]

The answer is c: <span>1960 J

</span>Potential Energy :
<span>PE = m x g x h = 40*9.8*5=1960
</span>

4 0