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sveta [45]
3 years ago
14

Suppose an elephant has a mass of 2850 kg. show answer No Attempt How fast, in meters per second, does the elephant need to move

to have the same kinetic energy as a 77-kg sprinter running at 7.5 m/s
Physics
1 answer:
Bad White [126]3 years ago
6 0

Answer:

1.23 m/s

Explanation:

The kinetic energy of the sprinter is:

KE = 0.5 * m(s) * v²

KE = 0.5 * 77 * 7.5²

KE = 2165.63 J

If the KE of the sprinter and the KE of the elephant are equal, hence:

2165.63 = 0.5 * m(e) * v²

2165.63 = 0.5 * 2850 * v²

=> v² = 1.52

v = √(1.52)

v = 1.23 m/s

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Two identical charges,2.0m apart,exert forces of magnitude 4.0 N on each other.What is the value of either charge?
storchak [24]

Answer:

\large \boxed{42\, \mu \text{C}}$

Explanation:

The formula for the force exerted between two charges is

F=k \dfrac{ q_1q_2}{r^2}

where k is the Coulomb constant.

The charges are identical, so we can write the formula as

F=k\dfrac{q^{2}}{r^2}

\begin{array}{rcl}\text{4.0 N}& = & 8.988 \times 10^{9}\text{ N$\cdot$m$^{2}$C$^{-2}$} \times \dfrac{q^{2}}{\text{(2.0 m)}^{2}}\\\\4.0 & = & 2.25 \times 10^{9}\text{ C$^{-2}$} \times q^{2}\\\\q^{2} & = & \dfrac{4.0}{2.25 \times 10^{9}\text{ C$^{-2}$}}\\\\& = & 1.78 \times 10^{-9} \text{ C}^{2}\\q & = & 4.2 \times 10^{-5} \text{ C}\\& = & 42\, \mu \text{C}\\\end{array}\\\text{Each charge has a value of $\large \boxed{\mathbf{42\, \mu }\textbf{C}}$}

7 0
3 years ago
Four equal masses m are so small they can be treated as points, and they are equallyspaced along a long, stiff mass less wire. T
gavmur [86]

The moment of inertia of a point mass about an arbitrary point is given by:

I = mr²

I is the moment of inertia

m is the mass

r is the distance between the arbitrary point and the point mass

The center of mass of the system is located halfway between the 2 inner masses, therefore two masses lie ℓ/2 away from the center and the outer two masses lie 3ℓ/2 away from the center.

The total moment of inertia of the system is the sum of the moments of each mass, i.e.

I = ∑mr²

The moment of inertia of each of the two inner masses is

I = m(ℓ/2)² = mℓ²/4

The moment of inertia of each of the two outer masses is

I = m(3ℓ/2)² = 9mℓ²/4

The total moment of inertia of the system is

I = 2[mℓ²/4]+2[9mℓ²/4]

I = mℓ²/2+9mℓ²/2

I = 10mℓ²/2

I = 5mℓ²

4 0
3 years ago
Saturated steam at 125 kpa is compressed adiabatically in a centrifugal compressor to 700 kpa at the rate of 2.5 kg⋅s−1. the com
Tpy6a [65]
M° = 2.5 kg/sec
For saturated steam tables
at p₁ = 125Kpa
hg = h₁ = 2685.2 KJ/kg
SQ = s₁ = 7.2847 KJ/kg-k
for isotopic compression
S₁ = S₂ = 7.2847 KJ/kg-k
at 700Kpa steam with S = 7.2847
h₂ 3051.3 KJ/kg
Compressor efficiency
h =  0.78
0.78 = h₂ - h₁/h₂-h₁
0.78 = h₂-h₁ → 0.78 = 3051.3 - 2685.2/h₂ - 2685.2
h₂ = 3154.6KJ/kg
at 700Kpa with 3154.6 KJ/kg
enthalpy gives
entropy S₂ = 7.4586 KJ/kg-k
Work = m(h₂ - h₁) = 2.5(3154.6 - 2685.2
W = 1173.5KW
5 0
3 years ago
A rock moving a 15m/s accelerates at 9.8m/s for 12s. what is the final velocity of the rock?
ryzh [129]
1.25 is the answer to tht if im right but could be wrong
4 0
3 years ago
The multi-link mechanism in the Variable Compression Turbo Engine _____, thus varying the compression ratio.
Fittoniya [83]

Answer:

A. Adjusts how far down the piston travels

Explanation:

This type of engine changes the possition of the piston in order to modify the compression chamber volume and therefore the compression ratio of the engine. The volume of the chamber is proportional to the run of the piston (how far down the piston travels)

This engine is used to achive the optimal compression rate in each individual stage.

5 0
3 years ago
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