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NISA [10]
3 years ago
14

Ice skaters often end their performances with spin turns, where they spin very fast about their center of mass with their arms f

olded in and legs together. Upon ending, their arms extend outward, proclaiming their finish. Not quite as noticeably, one leg goes out as well.Suppose that the moment of inertia of a skater with arms out and one leg extended is 2.9 kgm2 and for arms and legs in is 0.90 kgm2 . If she starts out spinning at 4.5rev/s, what is her angular speed (in rev/s) when her arms and one leg open outward?
Physics
1 answer:
nekit [7.7K]3 years ago
4 0

Answer:

Her angular speed (in rev/s) when her arms and one leg open outward is 1.4 rev/s

Explanation:

given information:

moment inertia of arm and leg when in, I₁ = 0.9 kgm²

moment inertia of arm and leg when extended, I₂ = 2.9 kgm²

angular speed when in, ω₁ = 4.5 rev/s

so, her angular speed (in rev/s) when her arms and one leg open outward is

L₁ = L₂

I₁ω₁ = I₂ω₂

ω₂ = I₁ω₁/I₂

     = 0.9 x 4.5/2,9

     = 1.4 rev/s

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suppose a 51 kg bungee jumper steps off the royal gorge bridge, in colorado. The bridge is situated 321 m above the arkansas riv
Akimi4 [234]

The total potential energy associated with the jumper at the end of his fall is 90,000 J.

The given parameters;

  • <em>mass of the jumper, m = 51 kg</em>
  • <em>height of the bridge. h  = 321 m</em>
  • <em>spring constant of the cord, k = 32 N/m</em>
  • <em>extension of the cord, x = 179 m - 104 m = 75 m</em>

The total potential energy associated with the jumper at the end of his fall is calculated as follows;

U = ¹/₂kx² + mgΔh

where;

<em>Δh is the change in height after falling </em>

U = ¹/₂(32)(75)²  + (51)(9.8)(0)

U = 90,000 J

Thus, the total potential energy associated with the jumper at the end of his fall is 90,000 J.

Learn more here:brainly.com/question/15731149

6 0
2 years ago
Why are airplanes filled with pressurized air and oxygen
zimovet [89]

Answer:

Airplane cabins are pressurized because as the airplane climbs higher in altitude, the air becomes very thin, this pressurization ensures that there is still enough breathable oxygen in the cabin to prevent everyone from suffering the effects of hypoxia and passing out.

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7 0
3 years ago
A helium weather balloon is filled to a volume of 219 m3 on the ground, where the pressure is 754 torr and the temperature is 29
Novosadov [1.4K]

Answer:

V_2 = 606.9 m^3

Explanation:

By ideal gas equation law we know that

PV = nRT

now we know that when balloon rises to certain level then the number of moles will remains same

so we can say

n_1 = n_2

\frac{P_1V_1}{RT_1} = \frac{P_2V_2}{RT_2}

now plug in all data to find the final volume of the balloon

\frac{754\times 219}{R(298)} = \frac{210 \times V_2}{R(230)}

V_2 = \frac{230\times 754 \times 219}{210 \times 298}

V_2 = 606.9 m^3

8 0
3 years ago
The weight of an astronaut on the moon is the same as on Earth.<br> True<br> False
Vaselesa [24]

Answer:

False

Explanation:

This is due to the gravitational pull, since the moon does not have the same force or gravity like Earth, your weight would change.

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•Expert•

Brainly Community Contributor

5 0
2 years ago
Read 2 more answers
A jet travels 1000 kilometers in 5 hours. What is its average speed?
nlexa [21]

Given:

Total distance = 1000 kilometer

Total time = 5 hours

To find:

Average speed = ?

Formula used:

v_{avg} = \frac{s}{t}

Where v_{avg} = average speed

s = total distance

t = total time

Solution:

Average speed of the jet is given by,

v_{avg} = \frac{s}{t}

Where v_{avg} = average speed

s = total distance

t = total time

v_{avg} = \frac{1000}{5}

v_{avg} = 200 km/ h

Thus, average speed of the jet is 200 km/h.

Hence, Option (A) is correct.


7 0
3 years ago
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