Frames of reference question

[2020vision]

Homework Statement

A smooth level table is centered on a platform which rotates.

- The uniform rotation is at: one revolution in 12 seconds
- Two perpendicular lines are drawn through the centre of the table, intersecting a circle of 1.20m radius at points: A', C', B' & D'.
- Two men, H' and I', sit on the platform at opposite ends of line A'C'
- A third man, J, is above the table so that he can observe the motion of a frictionless puck in a stationary frame of reference.
- J has four marks on the floor, forming two perpendicular reference lines AC and BC through the centre of the table.


Questions:
As H' passes A he gives the puck a sudden push so that it travels along line AC with a speed of 0.40m/s. Construct a vector diagram to show the velocity that H' gave the puck in J's frame of reference.

Make a diagram of the puck's motion as seen by H' and I'

Suppose that H' launches puck as he passes A so the I' will catch the puck as he passes D. Construct diagram which shows motion of puck in J's frame of reference. What is the speed of the puck in this frame of reference?

With what speed and in what direction can H' launch the puck as he passes A so that, as J sees it, the puck remains at A?

Homework Equations

Fc = mv^2/R
= 4pi^2rm/T^2

The Attempt at a Solution

I frankly don't know where to begin but for the first question I know that in J's frame of reference the puck will look like it is moving in a straight line.

To H' and I' the motion will look circular.

 

[jbsteele]

For the third question, the speed of the puck in J's frame of reference will be 0.40m/s.For the fourth question, I'm not sure what the answer is.

 

[Moetasim]

For the third question, the speed of the puck in J's frame of reference can be calculated using the formula Fc = mv^2/R where Fc is the centripetal force, m is the mass of the puck, v is its velocity and R is the radius of the circle (1.20m). The speed can also be calculated using the formula v = 2πr/T where T is the time for one revolution (12 seconds) and r is the radius of the circle (1.20m).

For the final question, H' can launch the puck with a speed of 0.40m/s in the direction of line AC so that, as seen by J, the puck remains at A. This is because the puck will continue to move in a straight line with a constant velocity, and since H' is moving at the same speed and direction as line AC, the puck will appear to remain at A in J's frame of reference.