HELP ME PLEASE: A flea is at point A on a horizontal turntable

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SUMMARY

The discussion centers on calculating the motion of a flea on a rotating turntable. The flea starts at point A, 8.1 cm from the center, and jumps vertically to a height of 4.11 cm while the turntable rotates at 33.9 revolutions per minute (rev/min). Key calculations include determining the linear displacement, angle of rotation, distance from the origin, angle with the x-axis, and linear speed after landing. The flea's airborne time was calculated to be 0.1832 seconds, and the linear displacement was found to be 0.0527 m.

PREREQUISITES
  • Understanding of rotational motion and angular displacement
  • Knowledge of kinematic equations for vertical motion
  • Familiarity with converting units (rev/min to m/s)
  • Basic trigonometry, specifically the use of arctangent for angle calculations
NEXT STEPS
  • Learn how to convert angular velocity from revolutions per minute to linear velocity
  • Study kinematic equations for projectile motion to analyze vertical jumps
  • Explore the concept of angular displacement in rotating systems
  • Investigate the relationship between linear speed and angular speed in circular motion
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Students studying physics, particularly those focusing on rotational dynamics and kinematics, as well as educators seeking to clarify concepts related to motion on rotating surfaces.

physicsnoob01
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A flea is at point A on a horizontal turntable 8.1 cm from the center. The turntable is rotating at 33.9 rev/min in the counterclockwise direction. The flea jumps vertically upward to a height of 4.11 cm and lands on the turntable at point B. Place the coordinate origin at the center of the turntable with the positive x-axis fixed in space and initially passing through A. The acceleration of gravity is 9.8 m/s2 .

1) Find the linear displacement of the flea.
Answer in units of m

2) Find the angle through which point A has
rotated when the flea lands.
Answer in units of degrees

3) Find the distance of point B from the origin
when the flea lands.
Answer in units of m

4) What angle does the radius drawn through B
make with the x-axis when the flea lands?
Answer in units of degrees

5) What is the linear speed of the flea after it
lands?
Answer in units of m/s

I am clueless as to how to get past the first part. Here was my work for part 1:
-convert 33.9 rev/min to m/s and got 0.2875 m/s
-used the equation y= a(t^2)/2 and got t= .0916 but that was only half the time, so I multipled by 2 and got time= 0.1832
-to find distance, i used d= v(t) and found the distance was 0.0527 m.

From here, I am lost. I have tried to do the arctan y/x equations to get the degrees but nothing is turning out right. And I am having difficulty understand parts 3-5 from the context of the question.

Any help is appreciated!
 
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physicsnoob01 said:
A flea is at point A on a horizontal turntable 8.1 cm from the center. The turntable is rotating at 33.9 rev/min in the counterclockwise direction. The flea jumps vertically upward to a height of 4.11 cm and lands on the turntable at point B. Place the coordinate origin at the center of the turntable with the positive x-axis fixed in space and initially passing through A. The acceleration of gravity is 9.8 m/s2 .

1) Find the linear displacement of the flea.
Answer in units of m

2) Find the angle through which point A has
rotated when the flea lands.
Answer in units of degrees

3) Find the distance of point B from the origin
when the flea lands.
Answer in units of m

4) What angle does the radius drawn through B
make with the x-axis when the flea lands?
Answer in units of degrees

5) What is the linear speed of the flea after it
lands?
Answer in units of m/s

I am clueless as to how to get past the first part. Here was my work for part 1:
-convert 33.9 rev/min to m/s and got 0.2875 m/s
-used the equation y= a(t^2)/2 and got t= .0916 but that was only half the time, so I multipled by 2 and got time= 0.1832
-to find distance, i used d= v(t) and found the distance was 0.0527 m.

From here, I am lost. I have tried to do the arctan y/x equations to get the degrees but nothing is turning out right. And I am having difficulty understand parts 3-5 from the context of the question.

Any help is appreciated!

What's with the arc tan? You know how long the flea was airborne, surely you can figure out how far the table has rotated in that time.

You correctly computed the velocity and airborne time of the flea, so surely you can also figure out how far it's flown?

By that time you should not have any difficulty with ## 4 & 5.
 

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