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2 years ago

3) Calculate the kinetic energy of a 7 kg mass traveling at a velocity of 4 m/sec.

Physics

2 answers:

Pepsi [2]2 years ago

7 0

Answer:

56 J

Explanation:

Formula to find the kinetic energy is :

$E_k$ = $\frac{1}{2}$ × m × v²

Here ,

m ⇒ mass

v ⇒ velocity

Let us solve now

$E_k$ = $\frac{1}{2}$ × m × v²

= $\frac{1}{2}$ × 7 kg × ( 4 ms⁻¹ )²

= $\frac{1}{2}$ × 7 × 16

= $\frac{1}{2}$ × 112

= 56 J

Hope this helps you :-)

Let me know if you have any other questions :-)

murzikaleks [220]2 years ago

4 0

$▪▪▪▪▪▪▪▪▪▪▪▪▪ {\huge\mathfrak{Answer}}▪▪▪▪▪▪▪▪▪▪▪▪▪▪$

Let's solve ~

Given terms :

Mass (m) = 7 kg

velocity (v)= 4 m/s

The formula to find kinetic Energy is ~

$\boxed{ \boxed{ \sf{ \frac{1}{2} m{v}^{2} }}}$

Now, apply the formula according to given situation

${ \qquad{ \sf{ \dashrightarrow}}} \: \: \sf \: \dfrac{1}{2} \times 7 \times ( {4)}^{2}$

${ \qquad{ \sf{ \dashrightarrow}}} \: \: \sf \: \dfrac{1}{2} \times 7 \times 16$

${ \qquad{ \sf{ \dashrightarrow}}} \: \: \sf \:7 \times 8$

${ \qquad{ \sf{ \dashrightarrow}}} \: \: \sf \:56 \: \: joules$

Therefore, the kinetic Energy of the car is 56 joules

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(D) Car A is not accelerating, but car B is accelerating.

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3 years ago

Suppose Gabor, a scuba diver, is at a depth of 15m. Assume that: The air pressure in his air tract is the same as the net water

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Complete Question

The complete question is shown on the first and second uploaded image

Answer:

Now the ratio of the gases in Gabor's lungs at the depth of 15m to that at

the surface is $\frac{(n/V)_{15\ m}}{(n/V)_{surface}} = 2.5$

The number of moles of gas that must be released is $n= 0.3538\ mols$

Explanation:

We are told from the question that the pressure at the surface is 1 atm and for each depth of 10m below the surface the pressure increase by 1 atm

This means that the pressure at the depth of the surface would be

$P_d = [\frac{15m}{10m} ] (1 atm) + 1 atm$

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The ideal gas equation is mathematically represented as

$PV = nRT$

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R is the gas constant = 8.314 J/mol. K

making n the subject we have

$n = \frac{PV}{RT}$

Considering at the surface of the water the number of moles at the surface would be

$n_s = \frac{P_sV}{RT}$

Substituting $1 atm = 101325 N/m^2$ for $P_s$ , $6L = 6*10^{-3}m^3$ for volume , 8.314 J/mol. K for R , (37° +273) K for T into the equation

$n_s = \frac{(1atm)(6*10^{-3} m^3)}{(8.314J/mol \cdot K)(37 +273)K}$

$= 0.2359 mol$

To obtain the number of moles at the depth of the water we use

$n_d = \frac{P_d V}{RT}$

Where $P_d \ and \ n_d \$ are pressure and no of moles at the depth of the water

Substituting values we have

$n_d = \frac{(2.5)(101325 N/m^2)(6*10^{-3}m^3)}{(8.314 J/mol \cdot K)(37 + 273)K}$

$= 0.5897 mol$

Now to obtain the number of moles released we have

$n = n_d - n_s$

$= 0.5897mol - 0.2359mol$

$=0.3538 \ mol$

The molar concentration at the surface of water is

$[\frac{n}{V} ]_{surface} = \frac{0.2359mol}{6*10^-3m^3}$

$=39.31mol/m^3$

The molar concentration at the depth of water is

$[\frac{n}{V} ]_{15m} = \frac{0.5897}{6*10^{-3}}$

$= 98.28 mol/m^3$

Now the ratio of the gases in Gabor's lungs at the depth of 15m to that at the surface is

$\frac{(n/V)_{15\ m}}{(n/V)_{surface}} = \frac{98.28}{39.31} =2.5$

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3 years ago

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3 years ago

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Answer:the human impact had some enivornmental effects.

Explanation:

For Climate it has no impact.

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While for the Topography,

Geology and Soils Minor, localized

impacts within project

footprint where observed and there was a potential major impacts within the footprint of the lake.

Surface Water Hydrology, it has minor short term adverse impact and a major, long term adverse impacts to Rough River hydrology between the dam and new outlet works Increased risk of major, long

term changes to hydrology upstream of dam. For the Groundwater there was no significant adverse impact. While the Vegetation had minor adverse impact Minor adverse impact.

Aquatic Resources had long-term beneficial impact.

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3 years ago

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Given that the frequency of an EM wave is 4THz, what is its wavelength?

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Answer:

The wavelength of the EM wave is 7.5 * 10⁻⁴ m

Explanation:

The velocity of a wave is related to its wavelength by the following formula;

velocity = wavelength * frequency

For an electromagnetic (EM) wave, its velocity is equal to the velocity of light, c = 3.0 * 10⁸ m/s

Given that the frequency and veloity of the given EM wave in the question is known, its wavelength is calculated as follows:

wavelength = velocity/frequency

where velocity of the EM wave = 3.0 * 10⁸ m/s;

frequency = 4THz = 4 * 10¹² Hz

wavelength = 3.0 * 10⁸m/s / 4 * 10¹² Hz

wavelength = 7.5 * 10⁻⁴ m

Therefore, the wavelength of the EM wave is 7.5 * 10⁻⁴ m

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3 years ago