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

In summary, a flea is on a rotating turntable at a distance of 8.1 cm from the center. It jumps vertically to a height of 4.11 cm and lands on the turntable at point B. The acceleration of gravity is 9.8 m/s2. The linear displacement of the flea is 0.0527 m. The angle through which point A has rotated when the flea lands is 4.93 degrees. The distance of point B from the origin when the flea lands is 8.1 cm. The angle that the radius drawn through B makes with the x-axis when the flea lands is also 4.93 degrees. The linear speed of the flea after it lands is 0.
  • #1
physicsnoob01
1
0
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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  • #2
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.
 

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

1. How did the flea get on the turntable?

The flea could have jumped onto the turntable from the ground or from another surface nearby, or it could have been placed there by someone.

2. How fast is the turntable spinning?

The speed of the turntable can vary, but it typically rotates at a rate of 33 1/3, 45, or 78 revolutions per minute.

3. Where is point A located on the turntable?

Point A could be anywhere on the circumference of the turntable, as long as it is on the horizontal surface.

4. Why is the flea at point A instead of staying in one place?

The flea is most likely moving due to the rotation of the turntable, which creates a centrifugal force that causes objects on the surface to move outwards.

5. How can the flea be helped?

The flea can be helped by gently removing it from the turntable and placing it back on the ground or a safe surface. It is important to handle the flea carefully to avoid harming it.

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