1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
irga5000 [103]
3 years ago
13

A gymnast is in a tucked position to complete her somersaults. While tucked her moment of inertia about an axis through the cent

er of her body is 16.0 kg-m² and she rotates at 2.5 rev/s. When she kicks out of her tuck into a straight position, her moment of inertia becomes 19.5 kg-m². What is her rate of rotation after she straightens out?
Physics
1 answer:
torisob [31]3 years ago
8 0

Answer:

\omega_s=12.8886\ rad.s^{-1}

Explanation:

Given that:

  • moment of inertia of tucked body, I_t=16\ kg.m^2
  • rotational speed of the body, N_t=2.5\ rev.s^{-1}
  • i.e. \omega_t=2\pi\times 2.5=15.708\ rad.s^{-1}
  • moment of inertia of  the straightened body, I_s=19.5\ kg.m^2

<u>Now using the law of conservation of angular momentum:</u>

angular momentum of tucked body=angular momentum of straight body

I_t.\omega_t=I_s.\omega_s

16\times 15.708=19.5\times \omega_s

\omega_s=12.8886\ rad.s^{-1}

You might be interested in
What is the magnitude of the total acceleration of point A after 2 seconds? The bar starts from rest and has a constant angular
monitta

Answer:

a_total = 2 √ (α² + w⁴) ,   a_total = 2,236 m

Explanation:

The total acceleration of a body, if we use the Pythagorean theorem is

          a_total² = a_T²2 + a_{c}²

where

the centripetal acceleration is

  a_{c} = v² / r = w r²

tangential acceleration

   a_T = dv / dt

angular and linear acceleration are related

         a_T = α  r

we substitute in the first equation

       a_total = √ [(α r)² + (w r² )²]

       a_total = 2 √ (α² + w⁴)

Let's find the angular velocity for t = 2 s if we start from rest wo = 0

        w = w₀ + α t

        w = 0 + 1.0 2

        w = 2.0rad / s

       

we substitute

        a_total = r √(1² + 2²) = r √5

        a_total = r 2,236

In order to finish the calculation we need the radius to point A, suppose that this point is at a distance of r = 1 m

         a_total = 2,236 m

7 0
3 years ago
The moons of Mars, Phobos (Fear) and Deimos (Terror), are very close to the planet compared to Earth's Moon. Their orbital radii
tankabanditka [31]

Answer:

0.2528

Explanation:

To calculate the period we need the formula:

T=\frac{2\pi r^{3/2}}{\sqrt{GM}}

Where r is the radius of the moon, G is the universal constant of gravitation and M is the mass of mars.

The period of Phobos:

T_{p}=\frac{2\pi r_{p}^{3/2}}{\sqrt{GM}}

The period of Deimos:

T_{D}=\frac{2\pi r_{D}^{3/2}}{\sqrt{GM}}

The ratio of the period of Phobos and Deimos:

\frac{T_{p}}{T_{D}}=\frac{\frac{2\pi r_{p}^{3/2}}{\sqrt{GM}}}{\frac{2\pi r_{D}^{3/2}}{\sqrt{GM}}}

\frac{T_{p}}{T_{D}}=\frac{\sqrt{GM}2\pi r_{p}^{3/2}}{\sqrt{GM}2\pi r_{D}^{3/2}}

Most terms get canceled and we have:

\frac{T_{p}}{T_{D}}=\frac{r_{p}^{3/2}}{r_{D}^{3/2}}

According to the problem

r_{p}=9,378km\\r_{D}=23,459km

so the ratio will be:

\frac{T_{p}}{T_{D}}=\frac{(9,378)^{3/2}}{(23,459)^{3/2}}=\frac{908166.22}{3593058.125}=0.25275 ≈ 0.2528

the ratio of the period of revolution of Phobos to that of Deimos is 0.2528

8 0
3 years ago
A Chinook salmon can jump out of water with a speed of 6.70 m/s6.70 m/s . How far horizontally dd can a Chinook salmon travel th
aksik [14]

Answer:

R = 3.88 m

Explanation:

As the Chinook salmon leaves the water till it gets back into the water it is performing a projectile motion with the following parameters:

V₀ = Launch Speed = 6.7 m/s

θ = Launch Angle = 29°

R= Range of Projectile= Horizontal Distance Covered by Chinook salmon= ?

The value of the range of a projectile is given by the following formula:

R = (V₀² Sin 2θ)/g

R = [(6.7 m/s)² Sin {(2)(29°)}/(9.8 m/s²)]

R = [(6.7 m/s)² Sin (58°)/(9.8 m/s²)]

<u>R = 3.88 m</u>

8 0
4 years ago
object x and y fall from a same height and object x is heavier than y which object would fall faster qnd y​
hjlf

Answer: They’d fall at the same speed, because air resistance is the only thing that makes an object fall faster than another. There’s a video somewhere on the internet of a bowling ball and a feather falling at the same speed in a vacuum, if you look for it. Hope this helps!

4 0
3 years ago
Sound is repeated near hills....<br>Why??? ​
madam [21]

Answer:

because there is many places for it to bounce of of creating another soundwave

5 0
3 years ago
Other questions:
  • A rabbit running away from a wolf jumps into a briar patch leaving the ground at an angle of 36º to the horizontal at a velocity
    7·1 answer
  • If an organism starts from only one cell,how do we get different body parts and organs
    12·1 answer
  • A train starting from rest picks up a speed of 20 m/s in 20 s while travelling on a straight path. It continues to move at the s
    6·1 answer
  • Why is there lightning in volcanic eruptions
    11·1 answer
  • What is the difference between acceleration and linear acceleration?
    12·1 answer
  • Calculate the power of the elevator if it can raise 290 kg of mass 30 flights of stairs (300 m) in 17 seconds
    9·1 answer
  • A cable capable of pulling 4,500 N snapped while trying to drag a 20,000 N compressor across the street. What is the coefficient
    6·1 answer
  • Explain the relationship between speed and distance, and velocity and acceleration.
    6·1 answer
  • Two magnets are held apart. Once released, the south pole of one magnet moves toward the north pole of another magnet until the
    5·1 answer
  • (PLEASE) You go sledding down a hill and are traveling toward the east. At 0s, your velocity is 0m/s. At 5s, your velocity is 30
    12·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!